EPA 910/9-82-0891
United States
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Air & Waste Management Division February 1984
xvEPA Residential Wood
Combustion Study
Task 6
Control Strategy Analysis
-------
RESIDENTIAL WOOD COMBUSTION STUDY
TASK 6
CONTROL STRATEGY ANALYSIS
-------
RESIDENTIAL WOOD COMBUSTION STUDY
TASK 6
CONTROL STRATEGY ANALYSIS
FINAL REPORT
PREPARED BY:
Robert L. Gay Ph.D., Consultant (Task 6 Manager)
4423 SW Hamilton Terrace
Portland, Oregon 97201
AND
William T. Green, President
Solutions for Energy and Environment, Inc. (SE2, Inc.)
1615 NW 23rd Avenue
Portland, Oregon 97210
PREPARED AND EDITED BY:
DEL GREEN ASSOCIATES, INC.
ENVIRONMENTAL TECHNOLOGY DIVISION
1535 N. Pacific Highway
Woodburn, Oregon 97071
Under Contract No. 68-02-3566 FROM:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Region X
1200 Sixth Avenue
Seattle, Washington 98101
Task Manager
Wayne Grotheer
April , 1983
-------
DISCLAIMER
This report has been reviewed by Region 10, U. S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policies of the U. S. Environmental Protection Agency,
nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
-------
THIS REPORT CONSISTS OF SEVERAL DIFFERENT PARTS.
THEY ARE LISTED BELOW FOR YOUR CONVENIENCE.
EPA 910/9-82-089a Residential Wood Combustion Study
Task 1 - Ambient Air Quality Impact
Analysis
EPA 910/9-82-089b Task 1 - Appendices
EPA 910/9-82-089c Task 2A - Current & Projected Air Quality
Impacts
EPA 910/9-82-089d Task 2B - Household Information Survey
EPA 910/9-82-089e Task 3 - Wood Fuel Use Projection
EPA 910/9-82-089f Task 4 - Technical Analysis of Wood Stoves
EPA 910/9-82-089g Task 5 - Emissions Testing of Wood Stoves
Volumes 1 & 2
EPA 910/9-82-089h Task 5 - Emissions Testing of Wood Stoves
Volumes 3 & 4 (Appendices)
EPA 910/9-82-089i Task 6 - Control Strategy Analysis
EPA 910/9-82-089J Task 7 - Indoor Air Quality
-------
TABLE OF CONTENTS
page
Abstract x
Executive Summary x-j
Taole of Contents -j-j
List of Tables vi
List of Figures v-j -j -j
I. Introduction I_1
A. Purpose i_]
B. Technical Approach j_2
C. Overview of Report 1-5
II. Leading Examples of Control Strategies Implemented II-l
to Reduce Air Pollution Impacts of Residential
Space Heating
A. Great Britain II-l
B. New Zealand II-2
C. Europe II-4
D. Rocky Mountain Region, USA II-7
E. Medford, Oregon, USA II-9
F. Portland and Eugene, Oregon, USA 11-10
III. A Control Strategy Evaluation Process III-l
A. The- Keppner-Tregoe Evaluation Process III-l
B. Selection of MUST and WANT Criteria HI-2
C. Weighting Factors for WANT Criteria IH-6
-------
TA3LE OF CONTENTS (Cont.)
page
III. A Control Strategy Evaluation Process (Cont.)
D. Use of MUST and WANT Criteria and II1-7
Risk Factors to Evaluate Control Strategies
E. Costs and Benefits III-9
F. Matrix Summary of Results III-ll
IV. Selection and Evaluation of Initial RWC IV-1
Control Strategy Elements
A. Identification of Potential RWC IV-2
Control Strategy Elements
B. Evaluation (Keppner-Tregoe) of IV-3
Control Strategy Elements
V. Generic Approaches to Reducing RWC Emissions - V-1
Quantitative Estimates of Emission Reductions
Achievable
A. Improving Burning Unit Design V-5
1. Improved Design of New Stoves/Furnaces V-5
2. Modifications of- Installed Stoves/Furnaces V-8
3. Improved Design, or Add-on devices, V-ll
for fireplaces
B. Reducing Wood Usage V-12
1. Reducing Home Heating Requirements - V-12
Weatherization
2. Improving Wood Fuel Quality V-15
3. Direct Restrictions on Wood Usage V-22
C. Improving RViC Operating Practices V-25
1. Initial Selection of Burning Unit -Sizing V-25
2. Operating Technique Modifications- V-27
3. Periodic Inspection of RWC Equipment V- 29
111
-------
TABLE OF CONTENTS (Cont.)
page
VI. Selection and Evaluation of Final RWC Control VI-1
Strategies
A. Final RWC Control Strategies Selected VI-1
for Evaluation
1. Stove/Furnace Testing and Certification vi-2
as a Prerequisite for Sale or Installation
2. Testing/Certification as Prerequisite VI-4
for Sale/Installation, Plus Tax Credit
3. Testing as Basis for Mandatory Labeling VI-5
Prior to Sale
4. Testing/Mandatory Labeling, VI-6
Plus Tax Credit
5. Testing/Rating by RWC Industry Trade VI-6
Association
6. Weatherization - All Households VI~7
7. Weatherization - Only Mandatory for vi-9
Households Installing Mew Wood Stove/Furnace
8. Firewood Moisture Control VI-10
9. Stove/Furnace Sizing VI-11
10. Encouraging Larger Firewood Piece Size VI-12
11. Require Fireplaces to Have Underfire VI-13
Air Source
12. Episode Control VI-14
13. Research and Development of Improved RWC VI-14
Equipment or Operating Procedures
14. Encouraging Alternative Fuels VI-16
15. Periodic Inspection of RWC Equipment VI-17
-------
TABLE OF CONTENTS (Cont.)
page
VI. Selection and Evaluation of Final RWC Control
Strategies (Cont.)
B. Keppner-Tregoe Evaluation of Final RWC VI-19
Control Strategies - Ranking The Final
Strategies Using WANT Criteria and Risk Factors
C. Selected Costs and Benefits of Final RWC VI-23
Control Strategies
0. Findings and Conclusions VI-24
VII. References VII-1
APPENDICES
Appendix A - Keppner-Tregoe Evaluation Process
Appendix B - RWC Control Strategy Elements
Appendix C - Ranking RWC Control Strategy Elements vs WANT Criteria
Appendix D - Estimated RWC Emissions Reduction Potential of
Generic Control Strategy Approaches
Appendix E - Ranking Final RWC Control Strategies vs WANT Criteria
Appendix F - Selected Costs and Benefits of Final RWC Control Strategies
-------
LIST OF TABLES
page
Table A - Criteria and Weight Factors Used in xii
Keppner-Tregoe Analysis
Table B - Description of Most Effective Control Stragegies xiii
Table C - Summary of Estimated Costs and Participate xvi
Emissions Reduction Benefits for Fifteen RWC
Emission Control Strategies
Table 1 - MUST Criteria III-3
Table 2 - WANT Criteria 111-4
Table 3 - Ranking of RWC Control Strategy Elements IV-4
vs WANT Criteria - Regulatory Actions
Table 4 - Ranking of RWC Control Strategy Elements IV-6
vs WANT Criteria -
Market Incentives/Disincentives
Table 5 - Ranking of RWC Control Strategy Elements IV-7
vs WANT Criteria - Public Information/
Technology Transfer Approaches
Table 6 - General Satisfaction Levels for IV-11
WANT Criteria #4
Table 7 - Comparison of Estimated Particulate Emissions V-3
Reductions Achievable by Generic RWC Control
Strategy Approaches
Table 8 - RWC Emissions Resulting from Six Hypothetical V-21
Cases of Wood Moisture Content Control
Table 9 - Fifteen Final RWC Control Strategies Evaluated VI-3
-------
LIST OF TABLES (Appendices)
page
Table Cl - Overall Ranking of Individual RWC Control C-2
Strategy Elements vs All WANT Criteria
Table C2 - Keppner-Tregoe Scores for Individual RWC C-7
Control Strategy Elements vs All WANT Criteria
Table Dl - Assumed 1980-2000 Baseline RWC Wood Fuel Use D-10
and RWC Emissions
Table D2 - Index Values for Certified and Non-Certified D-ll
Wood Stove/Furnace Use at Different Control
Strategy Coverage Rates
Table D3 - Particulate Emissions Reduction (%) Achievable D-15
at Five Control Strategy Coverage Levels
Table 04 - PEDCo Fireplace Source Tests: Comparison D-21
of Underfire Air and Electrostatic Precipitator
Table D5 - Emission Rates Calculated for a Range of D-29
Burn Rates Using Butcher and Del Green Equations
Table D6 - Emissions Per Day Resulting from Changes In D-33
Emissions Rates Caused by Changes in Burn Rates,
Calculated Using Butcher and Del Green Equations
Table D7 - Total Wood Burned, Heat and Emissions Output D-34
During a Ten-Hour Burn at Different Burn Rates
Table D8 - Scheme for Comparing Relative Emissions Associated D-37
with Two Overall Wood Use Rates
Table D9 - Comparison of Assumptions and Resulting Emission D-44
Reductions for Two Scenarios Regarding the
Effect of Weatherization
Table D10 - Examples of Variation of Wood Fuel Heating Value D-47
with Wood Species
Table Dll - Wood Storage Practices in Medford, Oregon - D-52
1981 State Survey Findings
Table D12 - Wood Moisture Content Distributions Evaluated D-56
VI 1
-------
LIST OF TABLES (Appendices) (Cont.)
page
Table D13 - Three Assumed Moisture Content vs Combustion D-60
Efficiency Curves for Stoves/Furnaces
Table D14 - Reduction in Expected 1990 and 2000 RWC D-76
Emissions, If New Stove Installations Were Not
Allowed After 1984, and 50% Compliance Occurred
Table D15 - Effect of Log Size on Particulate Emission Rates D-85
Table El - Fifteen Final RWC Control Strategies Evaluated E-l
Table E2 - Keppner-Tregoe Scores for Final RWC Control E-4
Strategies vs Twelve WANT Criteria; and Risk
Factors Assigned
LIST OF FIGURES
Figure A - Summary for Fifteen Final RWC Control Strategies xv
Evaluted of: Ranking vs Twelve WANT Criteria,
and Major Strategy Costs and Benefits
Figure 1 - Application of MUST and WANT Criteria to III-8
Evaluate and Rank RWC Control Strategies
Figure 2 - Assessment of Possible Adverse Consequences of 111-10
Strategy Implementation; or Risk Factors
Figure 3 - Effect of Wood Moisture Content on Fireplace V-17
Combustion Efficiency
Figure 4 - Effect of Wood Moisture Content on Stove/Furnace V-19
Combustion Efficiency
Figure 5 - Three Assumed Moisture Content vs Combustion V-20
Efficiency Curves for Stoves/Furnaces
Figure 6 - Summary of Fifteen Final RWC Control Strategies VI-20
of the Keppner-Tregoe Ranking vs WANT Criteria,
and Major Strategy Costs and Benefits
vm
-------
LIST OF FIGURES (Appendices) (Cont.)
page
Figure Al - Paried Comparison Work Sheet A-6
Figure Dl - Base Case 1970 to 2000 Projection for the D-9
Portland Metropolitan Area for Stove/Furnace
Wood Usage (S), Fireplace Wood Usage (F), and
Total Wood Usage (T)
Figure D2 - General Relationships Assumed Between Key D-25
Wood Burning Variables
Figure D3 - Two Different Representations of the Relationship D-28
Between Burn Rate and Emission Factor
Figure D4 - Relative Increase or Decrease (%) in Stove D-31
Emission Rates Estimated for an Array of Burn
Rate Changes Using the Del Green Equation
Figure D5 - Relative Increase or Decrease (%) in Stove D-32
Emission Rates Estimated for an Array of Burn
Rates Changes Using the Butcher Equation
Figure D6 - Effect of Wood Moisture Content on Fireplace D-49
Combustion Efficiency
Figure D7 - Effect of Wood Moisture Content on Stove/ D-55
Furnace Combustion Efficiency
Figure D8 - Three Assumed Moisture Content vs Combustion D-57
Efficiency Curves for Stoves/Furnaces
Figure D9 - Particulate Emissions As A Function of Fuel D-65
Moisture
Figure D10 - Albuquerque Pollution Signal Light D-71
Figure El - Potential Adverse Consequences (Risk Factors) E-18
of Implementing the Final Fifteen RWC Control
Strategies
IX
-------
ABSTRACT
This study developed and evaluated a comprehensive list of alter-
native strategies for controlling the ambient air quality impact of
residential wood combustion (RWC) in the Pacific Northwest. Over
seventy-five control strategy elements were initially evaluated, using
a Keppner-Tregoe evaluation process, which included five minimum (MUST)
criteria and twelve desirable (WANT) criteria. Twenty generic stragegy
approaches were evaluated, using available published information and
extensive assumptions, to estimate their potential ability to reduce RWC
particulate emissions. Based on the findings of these analyses, fifteen
RWC control strategies were selected and evaluated using the Keppner-
Tregoe process. Rough estimates of implementation costs were made.
A matrix summary of the fifteen strategies was prepared showing their
relative ranking based on all twelve WANT criteria, their estimated
costs, and benefits in terms of estimated particulate emission reduction
potential.
X'
-------
EXECUTIVE SUMMARY
The growth in residential wood combustion has been identified as a
significant contributor to non-attainment of total suspended particulate
ambient standards in several Pacific Northwest cities. Under the Clean
Air Act, each State is required to prepare a legally im-lementable plan
for bringing each non-complying geographical area into compliance. Tradi-
tionally, these State-prepared control strategies for particulate have
foccussed on industrial emissions and have been successful in substantially
reducing the industrial contributions. Attention now is turning towards
possible control of remaining major particulate contributors, including
residential wood combustion. Task 6 examines and evaluates possible control
strategies to reduce residential wood combustion emissions.
Seventy-five possible control strategies were selected, including those
strategies that have been implemented somewhere in the world, those suggested
by knowledgeable air pollution control agency personnel, and those suggested
by project members. A systematic ranking system was developed using the
Keppner-Tregoe evaluation process (see Table A) and each of the 75 control
strategies ranked. The fifteen highest ranking strategies were further
evaluated as to costs, projected emissions reductions, and significant
advantages and disadvantages. Table B describes each of the fifteen strategies,
it's ranking and the major advantages and disadvantages. Table C lists the
estimated costs and total particulate emission reductions associated with each
control strategy.
The ranking and evaluation process necessarily included two major
sources of uncertainty. These are the assumptions required to be made
because of lack of data (costs and projected emission reductions, for example),
and the somewhat subjective values assigned during the ranking process.
Projecting the response to public education programs, public acceptance of
control strategies, and the political feasibility in passing the necessary
laws, were particularly difficult to assess clearly. Any specific control
strategy development would require in-depth analysis of local conditions and
XI
-------
TABLE A
Criteria and Weight Factors Used
In
Keppner-Tregoe Analysis
CRITERIA
MUST Criteria
1. Reduce air pollution impacts from RWC
Meet legal requirements
2
3
4.
5,
Widely applicable to RWC equipment or
operating practices
Must not increase safety hazard
Can be implemented within five years,
unless long-term benefits great
WEIGHT FACTOR*
Mandatory
Mandatory
Mandatory
Mandatory
Mandatory
WANT Criteria
1. Reduce average RWC emissions/household
2. Reduce number of RWC households
3. Widely applicable
4. Maximum public acceptance
5. Discourage worst appliances/practices
6. Minimum consumer cost
7. Uses proven technology
8. Minimum circumvention of control measure possible
9. Maximum agency administrative feasibility
10. Encourages innovative technology
11. Minimum free market interference
12. Promotes conservation/use of renewable resources
(except wood)
13
13
10
9
9
6
5
4
3
2
2
1
* These weight factors were calculated using an analytic tool called
"paired comparison". For further details, see Appendix B of the
complete report on Task 6.
XI 1
-------
TABLE B
Description of Most Effective Control Strategies
Strategy Description
Keppner - Tregoe
Rank1 I Points
Major Advantage(s)
Major Disadvantage(s'
Mandatory testing/certif-
ication of all new wood
stoves, with only clean
burning stoves allowed to
be sold. Tax credit
(rebate) of $400 to
purchaser.
Mandatory testing/certif-
ication of all new wood
stoves, with only clean
burning stoves allowed to
be sold. No tax credit.
Encourage use of larger
firewood piece size
through public education
Mandatory testing and
labeling of all new wood
stoves by pollution and
efficiency levels, but
all stoves can be sold.
Tax credit for cleaner
units.
Encourage use of other
fuels by reducing costs
of conventional fuels,
encourage solar energy
use, restrict availability
of wood.
1
535
508
490
469
458
Significant emissions reduction
Significant emissions reduction;
less expensive than above stra-
tegy
Inexpensive; public acceptance
expected to be high since bigger
pieces mean less work split-
ting wood
Substantial public acceptance
expected; significant emissions
reductions (but less than when
only clean stoves are sold)
Technology available
Expensive
Lack of public acceptance due
to higher stove costs.
None
Expensive
Encourageing oil use contrary
to federal policy. Poor public
acceptance for restricting wood
supplies. Other heating sources
may not be available or' maybe
too expensive.
Refer to text for explanation of assumptions used during ranking process.
-------
TABLE B (Cont.)
Strategy Description
Keppner - Tregoe
Rank
1
Points
Major Advantage(s)
Major Disadvantage(s)
Government funded research
and development of improved
equipment, operating pro-
cedures, and testing
methods.
Promote proper sizing of
new wood burning units of
public education and re-
quiring appropriate label-
ing of new units. Could
limit size with building
permit restriction.
Mandatory testing and
labeling of all new wood
stoves by pollution and
efficiency levels, but
all stoves can be sold.
No tax credits.
Mandatory weatherization
of all households to a
cost effective level
(fuel savings greater
than expense).
Stove testing and rating
by Trade Association.
10
445
443
438
432
422
The lack of data currently
hampering efforts to evaluate
control efforts and stove design/
operating procedures will be
deminished.
Minor cost, good public accep-
tance. Reduction of creosote
and fire problems
Good public acceptance
Energy conservation for all
fuels
High public acceptance.
Specific emissions reductions
are not quantifiable
Slight user inconvenience in
that more frequent charging of
smaller units will be required
None
Public resistance, expensive
Totally voluntary, relies on
vigorous implementation by
Trade Associaiton with minimal
return for Trade Association
-------
TABLE B (Cont.)
Strategy Description
Keppner - Tregoe
Rank
Points
Major Advantage(s)
Major Disadvantage(s)
Mandatory weatherization
for households buying new
or replacement wood burn-
ing devices to a cost
effective level.
Encourage burning of drier
firewood by public educa-
tion, restricting firewood
gathering to as far in
advance of heating season
as possible, and require
firewood suppliers to
state moisture content.
Voluntary curtailment of
RWC during air pollution
episodes. Mandatory cur-
tailment required if
voluntary curtailment does
not work.
Annual inspection and main
tenance of woodburning
units, including cleaning
chimney.
Require underfire air for
new fireplaces (building
code or ordinance).
11
411
12
400
13
381
14
321
15
292
Will discourage new woodburning
units
Minimal cost. Potential for
substantial decrease in emis-
sions
Minimal cost. Reduction of
emissions during periods of
worst air pollution
Will encourage replacement of
catalysts at appropriate times;
substantial safety benefits
expected
Inexpensive, substantial reduc-
tion in fireplace emissions
May be perceived as unfairly
affecting one group of people,
Expensive
Public resistance to restricting
times of firewood gathering
Dependent on public cooperation
Effect on annual attainment of
standards unknown
Extremely high resistance from
public ; high expense
Fireplaces will be used less in
future, be a relatively small
proportion of emissions
-------
-------
TAB IE. C*
Summary of Estimated Costs and Particulate Emissions
Reduction Benefits for Fifteen RWC
Emission Control Strategies
Control Strategy
1. Mandatory testing/certification.
tax credit
2. Mandatory tes ting/certi flcation ,
no tax credit
3. Encourage use of larger pieces
of firewood
4. Mandatory testing/labeling, tax
credit for cleaner units
5. Encourage use of other fuels
and energy sources
6. Government funded research and
development
7. Promote proper sizing of
wood stoves
8. Mandatory testing/labeling, no
tax credit
9. Mandatory weatherlzatlon - ill
households. Cost effective
10. Stove testing/rating by Trade
Association
11. Mandatory cost effective weatheHza-
tton - new or replacement RWC
households
12. Encourage burning of dry firewood
13. Curtailment of RWC during air
pollution episodes
14. Annual Inspection/maintenance
of installed units
15. Require underflre air for new
fireplaces
Costs
Start-up
5 50.000
$ 50,000
...
J 50,000
UNKNOWN
UNKNOWN
...
$ 50,000
S 50,000
...
$ 25.000
...
...
Admin. /Year
$130.000
$130,000
$ 45.000
$160,000
$ 45.000
$130,000
$150.000
$130,000C
$ SO, 000
$ 45.000
$ 8,000
$1 ,000.003
$200,000
Other
$400/un1t
tax credit
...
...
$4 00/unlt
In credit
...
$1450 per
household
$1450 per
househol d
:::
- -
...
1985-
3
2
11.5
1
--
1
1
..
6.2
33d
UNKNOWN
1990
11
8
11.5
5
7
3
3.5
3
3.5
6.2
33d
1
1995
30
22
11.5
15
--
8
16,4
8
7.0
6.2
33d
2000
39
30
11.5
21
10.5
11
11
6.2
33d
2
1985*
$180,000/1*
$ 70,000/1
$ 3,900/1
$570.000/1*
$140.000/1
$140.000/1
...
$ 7.300/1
$ 400/1'
1990
$48.600/1*
$16,900/1
$ 3,900/X
$113,000/1*
$ 6.400/1
$ 45,000/1
$ 9,100/Ib
$ 45,000/1
J 14 .300/1*
$ 7 .300/1
5 400/1'
$200.000/1
1995
$17 .800/1*
$ 6,100/1
$ 3,900/1
$37,500/1*
$16.700/1
$21.400/Ib
$16,700/1
$ 7.100/lk
$ 7.300/1
$ 400/ld
2000
$13.700/1*
$ 4,400/1
$ 3,900/1
$16.800/1*
$ 4.300/1
$12,000/1
...
$12.000/1
$ 7,300/1
$ 40o/rd
$100.000/1
* Assume 1980 as base year.
a Assume 1000 new wood stoves/year.
b Fuel savings exceed cost of weatherization. Annual costs only for
administrative expenses.
c Costs paid by private sector.
d Reduces participate emissions only during episodes. Effect on annual TSP
levels unknown.
* Refer to text for discussion of assumptions used in arriving at estimated
costs and participate reductions.
XVI
-------
-------
re-evaluation of these control strategies. However, this study should assist
control agency personnel in the'initial selection of possible control strategies
for further evaluation'.
Best Emissions Reductions
The two strategies which ranked highest also provide the highest
percentage reduction in RWC particulate emissions-- 39% and 30% respectively,
by the year 2000. Both involve mandatory testing/certification and pro-
hibition of the sale of wood stove/furnace models which can't comply with
government emission standards (<5 g/kg suggested standard).
This strategy approach is very effective over time in lowering emissions,
as these new units replace existing stoves/furnaces which emit, on the
average, four times as much particulate pollution. This approach requires
years for its maximum benefits to accummulate.
Both strategies restrict consumer choices dramatically, which could
produce public opposition, if such limitations are perceived to have caused
the price of remaining stoves to rise unreasonably. To help avoid this, the
top ranked strategy includes a financial incentive (33% tax credit estimated
at $400/unit in 1984). This in turn makes this the most expensive strategy
of all those reviewed, with likely annual costs (tax revenues foregone) in
the millions of dollars for a program on statewide scope.
Such costs appear to be appropriate and manageable. For example, Oregon
has spent hundreds of millions of dollars over the last decade in pollution
control tax credits for industrial control equipment. The growing evidence
that RWC particulate emissions approach or surpass those of industrial sources
in many cases (e.g., Portland, Oregon) argues strongly for shifting some
pollution control tax credit resources to address RWC.
Another potential hurdle in implementing the testing/certification
approach are possible difficulties in enacting legal authority to prohibit
commercial sales of non-certified burning units.
Least Cost Emission Reductions
Based on the analyses and assumptions in this report, a group of
strategies emerge which potentially offer significant RWC emissions reductions,
xvn
-------
with minimal cost and inconvenience, and high public acceptance. The strategies
with their estimated RWC emissions reductions in parenthesis include:
encouraging larger firewood piece size (11.5%), encouraging use of firewood with
an appropriate moisture content (6.2%), encouraging use of properly sized
stoves (7-10%), and voluntary episode controls (33% or more on episode days).
All are based on public education. The first three could be implemented
jointly with annual administrative costs that are modest (estimated less than
$100,000 in Appendix F). The combined emissions reductions of these three
strategies is 23% by about 1990 [(1.0 - .062)(1.0 - .115)(1.0 - .07) = .773.
However, it should be noted that the equations used to estimate emissions
reductions from all three strategies are based on limited lab tests by a
single researcher (different in each case), although the general phenomena
may have been observed by several reseachers. These strategies are thus prime
candidates for further research to determine whether they really do offer the
most cost-effective RWC controls.
Research and Development
Despite the fact that no emission reduction estimate could be made for
this strategy, it still ranked highly (5th overall) in the Keppner-Tregoe
process. It is the key which could open the door to emission reductions
from a wide range of strategies. This point is illustrated in the section
above which discusses educational strategies to change operating practices.
These strategies may well be the most cost-effective strategies for reducing
RWC emissions over the next 10-20 years, but additional research is needed to
verify this and to evaluate improvements in stove operation and design.
Of all research and development funding categories, the greatest need
appears to be for the development of simpler and less expensive emission
measurement techniques for RWC. This not only would facilitate testing/cer-
»
tification and testing/labeling strategies, but would a-lso help researchers
evaluate how RWC emissions are affected by key variables such as moisture
content, piece size, and charge size.
Emissions Testing/Labeling Strategies
Three strategies requiring testing/labeling of woodburning devices for
xvm
-------
efficiency and emissions ranked 4th, 8th, and llth respectively in the overall
ranking. All -offer potential significant emissions reductions by 1990-2000.
The largest reduction occurs with a significant financial incentive (33% tax
credit) which also greatly increases the program costs.
The emissions reduction benefits are significantly less than those from
Strategies #1 and #2 which restricted sales to clean burning units only. The
dramatic limitation on consumer choice was at once a major strength and lia-
bility for the testing/certification strategies. The three-testing/labeling
strategies preserve consumer choice. In so doing they are likely to be much
less effective in promoting the purchase and installation of stoves emitting
<5 g/kg. Even with the tax credit option, there are likely to be cheaper
stoves available with much poorer emission characteristics.
Weatherization
The two weatherization strategies (mandatory weatherization for all
households and mandatory weatherization only for households purchasing
new stoves) were ranked 9th and 12th. Both were judged to have relatively
poor public acceptance due to their mandatory nature, and high initial
cost (despite eventual "payback" through fuel savings).
In the short-term, weatherization of a household does not yield an
emission reduction equivalent to the reduction in heat (BTU) requirements,
because 1) the operator may continue to burn as much wood as before and
rely less on conventional fuels, 2) the operator may burn at a slower burn
rate with a higher emission factor, and 3) most operators will not immediately
replace their existing stove with a smaller less-polluting unit. Most of the
short-term reduction is due to burning on fewer days since better insulated
houses have to be heated on fewer days.
In the longer term, when the owner of a weatherized home replaces his
existing stove, additional emission reduction benefits may occur, if an
education program cnoviences him to purchase a smaller stove, which can be
operated in a manner that generates lower particulate emissions.
Public Acceptance
The strategies rated most acceptable to the public at large and to RWC
xix
-------
households in particular generally were those involving the least incon-
venience and/or costs. For example, the strategy encouraging larger firewood
piece size ranked third overall, with the highest possible scores in "public
acceptance" and "minimizing consumer costs". It costs individuals nothing,
and reduces the work of splitting wood, while affording significant (11.5%)
estimated emissions reductions.
The labeling strategies ranked next highest in public acceptance. They
provide information which helps the consumer choose a new stove, without
limiting his choices or raising stove prices. The version with a subsidy
(tax credit) ranked highest of these three.
Ranking similarly high in public acceptance were encouraging use of low
moisture firewood and proper stove sizing. Both provide information and rely
on voluntary compliance with little or no enforcement pressures (stove sizing
could involve an installation permit review process). Episode controls which
ranks almost as high in public acceptance, also would rely on voluntary com-
pliance except under very severe pollution levels. Research and development
easily ranks high in public acceptance, offending no one.
no one.
Lowest Ranked Strategies
The strategies which ranked last under the Keppner-Tregoe analysis were
fireplace underfire air and periodic inspection. Fireplace underfire air
has been reported to reduce emissions by 40%, but this is based on a single
lab test. This strategy does not address the largest category of RWC emis-
sions at all -- stove emissions -- and it applies only to new fireplaces.
It was not assumed to have high public acceptance.
Periodic inspection, although it has significant safety benefits, was
not assumed to have any certain emission reduction benefits in most cases.
The inspection strategy appeared likely to have emission reduction potential
only in areas with either 1) a high fraction of catalyst stoves (catalyst
lifetimes are about two years), 2) a high fraction of new technology high
efficiency units (more sophisticated units may be more likely to need main-
tenance to maintain high performance), or 3) a limited number of stove models,
xx
-------
since inspections then would have greater potential for recognizing rela-
tively poor performance and maintenance needs. Periodic inspections were
assumed to have poor public acceptance.
Stove Modifications or Add-on Devices for Existing Stoves
This area of emission reduction was initially evaluated but was not
included in the more detailed analysis for several reasons. Data generally
is lacking or not conclusive in supporting the effectiveness of add-on
devices (such as catalysts) or stove modifications (such as lining stoves
with firebrick). Other concerns included the cost, and the long-term effec-
tiveness of control measures.
Zoning Restrictions Prohibiting New Wood Stoves in Specific Areas
This approach has been used in other areas, but was rejected for the
Pacific Northwest because of the expected and insurmountable public resistance,
xxi
-------
j^ liiTKOCUCTION
This section aescribes: the purpose of the analyses conducted
under Task 6 (Section A); a summary of the technical approach used
in selecting and evaluating control strategies (Section B); and, an
overview of the organization of the rest of this report (Section C).
A. PURPOSE;
The primary purpose of Task 6 is to develop and evaluate a com-
prehensive list of reasonable alternative strategies which could be
applied in the Pacific Northwest to control the ambient air quality
impact of residential wood combustion (RWC).
Many potential RWC controls were considered, including some which
are admittedly costly, politically controversial, or otherwise difficult
to implement. The intent was to be as comprehensive as reasonably
possible in the selection of control strategy elements for initial
evaluation. The ultimate objective was to evaluate a list of RWC
control strategies which represented the major options for controlling
RWC pollution available today.
It was emphatically not the intent of this study to discourage
RWC per se, but rather to identify the most potentially effective ways
to minimize its pollution impact. This should be remembered when
reviewing the (Keppner-Tregoe) evaluation process itself, which contains
criteria that may, at first glance, appear to be supportive of such
outcomes as "reducing the number of RWC households". This criteria
seemed fundamentally appropriate in evaluating the potential effects
of a given strategy - asking in effect, "to what extent will this
strategy discourage new RWC households, or encourage existing RWC
households to discontinue RWC?" Also only one of the final strategies
considered was designed to intentionally reduce the number of RWC
households, by encouraging use of conventional fuels like, oil, gas,
and electricity. This too seemed a necessary inclusion in any com-
prehensive consideration of RWC control strategies.
1-1
-------
b. SUMMARY OF TECHNICAL APPROACH
Leading examples of RWC control strategies implemented elsewhere
were researched and described, using literature reviews and personal
contacts with knowledgeable individuals.
3ased on the information obtained from all sources, an initial
list of about 75 potential control strategy elements was assembled
(Appendix A). A number of these were not necessarily considered
feasible, but were included for comprehensiveness. The strategies
considered were grouped in the following categories:
1. Strategies to reduce emissions by improved burning unit design;
2. Strategies to reduce emissions by reducing wood usage, and;
3. Strategies to reduce emissions by improving on operating procedures
for wood burning appliances.
Within these categories, strategies were organized by methods of
achieving the strategies, including:
1. Regulations requiring compliance with various wood burning rules.
2. Market incentives to achieve the strategies.
3. Information distribution/technology transfer to speed development
and implementation of strategies.
The Keppner-Tregoe decision analysis process was used to evaluate
and rank the comprehensive list of proposed strategy elements. For
this process, MUST and WANT criteria were developed, which represented
strategy characteristics considered essential and desirable, respec-
tively. WANT criteria were weighted according to their relative
importance, using a method of paired comparison.
The full Keppner-Tregoe evaluation consisted of three steps.
First, strategy elements which did not satisfy all MUST criteria were
eliminated from further consideration. Second, each strategy element
1-2
-------
was rated on a scale of 1 - 1U as to how well it satisfied each WANT
criteria. Each rating was niul ti pi i ec by the weighting factor for that
UANT criteria. The resulting scores were summed over all WANT criteria
to give a total score reflecting how well each strategy element
satisfied all of the WANT criteria, simultaneously. These total scores
constituted a preliminary ranking of all the strategy elements as to
,.''mch were the most effective, practical and publicly acceptable.
T;ie tnirc step in the Keppnc-r-Tregoe process evaluated possible
adverse consequences of implementing a given strategy, generating an
"adverse consequence score", or risk factor. This involved estimating
on a scale of 1 - 10, both the likelihood of occurrence and the serious-
ness of the adverse impact; and then multiplying the two numbers to
obtain an adverse consequences score. Adverse consequences scores
also were summed for each strategy considered, but they were not
»
subtracted from the scores based on satisfaction of WANT criteria.
Instead, their magnitude is noted, and a common sense -judgement made
as to whether the adverse consequences were serious enough to warrant
changes in the preliminary ranking of strategies.
The initial comprehensive list of individual strategy elements
was evaluated using only the first two steps of the Keppner-Tregoe
process - i.e., without considering risk factors. Those strategy
elements which ranked high were given further consideration for
inclusion in the final list of RWC strategies evaluated.
A second analytical approach to selecting strategies for final
evaluation involved consideration of a list of twenty generic
strategy approaches - i.e., basic general ways to reduce RWC emissions,
such as improving (decreasing) burning unit emission rates, weatherizing
homes to reduce space heating requirements, wood moisture control,
etc.. Rough estimates were developed of the potential (particulate)
emissions reductions achievable by these strategy approaches. A
summary table of relative emissions reduction potential was prepared.
These particular analyses were often speculative due to scarcity
of emissions test data, and the need to estimate variables such as
1-3
-------
"'..hot fraction cf the public would be Induced to reduce their firewood
moisture content oy reproving their wood storage practices?" However,
despite the many assumptions required, this analysis proved valuable
in requiring examination of available test data and fundamental theories
of wood combustion, if, order to estimate possible emission reductions
quaniitatively.
oasec on all these analyses, a list of fifteen final RWC control
strategies was prepared, which was intended to represent a reasonably
comprehensive range of control options available to regulatory agencies.
Soine of the final strategies were patterned after strategies implemented
in an actual city or region. Major elements of the final strategies
were selected because of their relatively high estimated emission
reduction potential,or a high ranking in the initial Keppner-Tregoe
evaluation of strategy elements, or a combination of such considera-
tions. The final strategies selected were kept simple, to enable the
final Keppner-Tregoe analysis to evaluate and rank a range of clearly
discreet approaches.
Costs and benefits of the final strategies also were estimated
and compared. Dollar costs, to both public and private sectors, of
implementing each strategy or category of similar strategies, were
considered separately, although cost factors also were included in
some of the WANT criteria used. The types of costs considered included:
1) public sector: agency costs to implement a strategy; public costs
to comply with regulatory requirements, or increased consumer costs
for wood burning caused by strategies; and 2) private sector: costs
to comply with regulatory requirements, or to take advantage of
incentives or meet competition caused by strategies. These cost
estimates are admittedly rough, but their assumptions and uncertainties
are spelled out, as much as possible. They also were based where
possible on the experience of established control programs. Any sig-
nificant benefits associated with particular strategies, in particular
to their effects on RWC emissions also were considered separately,
1-4
-------
e.g., any improvement in safety factors associated with wood burning
as a result of a strategy to control pollution. Some benefits such
as promotion of energy conservation, are built into WANT criteria in
the evaluation process.
A full (3-step) Keppner-Tregoe analysis was performed on the
final fifteen strategies. The result was a final overall ranking of
the fifteen strategies based on all twelve WANT criteria. This ranking
was displayed in matrix format along with the costs and benefits
identified for each strategy. The matrix summarizes the information
developed in this analysis on the relative ability of these fifteen
strategies to reduce RWC air quality impacts with maximum effec-
tiveness, practicality and public acceptance, and minimum cost and
adverse consequences. Narrative findings and conclusions also are presented.
C. OVERVIEW OF REPORT
The remainder of this report is organized as follows: '
Section II describes leading examples of control strategies
implemented to reduce the air pollution impacts of
residential space heating.
Section III describes the Keppner-Tregoe process as it
was adapted to evaluate RWC control strategies. This
includes descriptions of the selection of MUST and WANT
criteria, and the determination of weighting factors for
WANT criteria.
Section IV describes the comprehensive initial list of
seventy-five RWC control strategy elements' and its evalu-
ation using an abbreviated Keppner-Tregoe process.
Section V describes the quantitative estimates of RWC
emission reductions achievable by twenty generic strategy
approaches.
1-5
-------
Section VI describes the selection and evaluation of fifteen
final RWC control strategies, using the full Keppner-Tregoe
process, including the matrix summary of their final
ranking, costs, and benefits.
Section VII lists information sources used in this study
(References).
1 Appendix A describes details of the Keppner-Tregoe process.
Appendix B describes the individual RWC control strategy
elements selected for evaluation.
Appendix C describes and documents the ranking of control
strategy elements, including the Keppner-Tregoe scores
of each strategy element versus each WANT criteria.
Appendix D describes the assumptions and rationale behind
the quantitative estimates of emission reduction potential
of generic RWC control strategy approaches.
Appendix E describes and documents the Keppner-Tregoe
evaluation and ranking of the final fifteen RWC control
strategies.
Appendix F describes and estimates the costs associated
with implementation of the final RWC control strategies;
selected benefits also are discussed.
1-6
-------
II. LEADING EXAMPLES OF CONTROL STRATEGIES
IMPLEMENTED TO REDUCE AIR POLLUTION IMPACTS OF
RESIDENTIAL SPACE HEATING
This section describes leading examples of control strategies
implemented in various places in the world to abate air pollution
problems from residential space heating. Some of these approaches
were designed to address air pollution problems arising from the use
of solid fuels, such as coal or wood. Other programs were more general
in that they were concerned vvith any home heating equipment based on
fuel combustion. Some also were concerned not only with air pollution
emissions, but also safety factors, and the overall energy efficiency
of home heating equipment. This points up the fact that some basic
RWC control strategy elements - e.g., weatherization, or inspection
of home heating devices - inherently have broader objectives and
benefits than pollution control, alone. Control of RWC pollution
problems may best be accomplished in efforts which combine the objec-
tives and resources of programs concerned with environmental quality,
fire safety, and energy conservation.
The following descriptions of control programs are not exhaustive.
It presents leading examples of different approaches tried in various
countries to address a variety of situations. The descriptions focus
on the general types of regulatory actions, incentives and public
information methods employed which could be used or adopted for control
of RWC air pollution impacts in this country. The reader is encouraged
to consult the references provided for additional details on these
programs.
A. GREAT BRITAINlf
During a 1952 London "fog" episode, 4000 deaths were attributed
to high sulfur dioxide and particulate pollution from residential coal
II-l
-------
burning. This prompted the British government to establish a control
program through a 1956 British Clean Air Act which included the
following elements:
Establishment of Smoke Control Areas in densely populated urban
centers with heavy coal burning.
In these areas, residential coal burning which produced smoke
was prohibited. Burning was allowed only with "smokeless"
(low smoke) stoves or smokeless (low volatiles) fuels. These
v/ere rated by specific British standards, based on testing
.-,y a British nationalized firm, the National Coal ^oara.
f\ /O"-: reoate on the cost of a smokeless replacement coal stove
was subsidized by the British government. Additional subsidies
were available in the case of extreme economic hardship.
Since 1956, over fifteen coal-based smokeless fuels and eleven
smokeless coal stoves have been certified for use in smoke control
areas. Today, London has 70% greater December sunshine, better winter
visibility, and reduced labor and expense for laundry and house clean-
ing. Active government involvement, and the stove and fuel performance
rating system and standards, encouraged significant technological
improvements to occur in a relatively short time. The 70% subsidies
unquestionably accelerated use of the improved stoves and fuels.
The standardized emissions test methods developed for coal do
not capture and measure much of the condensible organic emissions.
This is an especially important weakness related to RWC, since most
RWC emissions are organic.
3. riEW ZEALAND15
Calm winter nights, and widespread burning of indigenous coal
or wood fuels for domestic heating, contribute heavily to air pollution
II-2
-------
levels In INCW Zealand cities. For example, in iNew Zealand's largest
city (Christchurch ) winter smoke levels frequently exceed the World
Health Organization's recommended goal of 100-150 yg/m . (New Zealand
has no ambient air quality standards.) Cleaner burning fuels such
as oil and gas are costly and less available. The government of New
Zealand has decided that people should retain the option to burn local
j^c. "i anc wood fuels, ano has implements^; Measures to 'ielp reduce its
adverse air pollution impacts.
New Zealand's 1972 Clean Air Act established air pollution control
requi renients for both industrial and domestic sources. Patterned
closely on the 1956 British Clean Air Act, the ,,ew Zealand Act
autnor'tzes local governments to establish Clean Air Zones to control
domestic smoke pollution. Within these zones the local government
can apply in total or in part the following Clean Air Zone provisions:
Only approved domestic fuel burning equipment may be installed
as new or replacement units.
Acceptable fuels may be prescribed - e.g., the sulfur content
of domestically burned coal must be £0.5%.
Acceptable installation and/or operating practices for domestic
fuel burning equipment may be prescribed - e.g., whether stoves
may be banked ("airtight" operating conditions) for overnight
operation.
To date only Christchurch City Council has implemented Clean
Air Zones, and has applied their provisions only to new and voluntary
replacement units. No subsidy is available to encourage replacement
with cleaner units.
Standardized testing of appliances under various burning pro-
cedures is necessary to support this regulatory system. This was
initially done (until 1980) by the privately funded Coal Research
Association, in cooperation with a government control agency (Department
of Scientific and Industrial Research). British testing procedures,
II-3
-------
,,.uuTMea to suit New Zealand fuels and conditions are used. Because
,,ooo burning appliances have increased their competition with coal
burning appliances, an independent laboratory recently has been con-
tracted for the standardized testing used for type-approval of heaters'.
Also a different government agency (Department of Health) has set up
rest facilities for basic research to develop cleaner burning equip-
,.
-------
domestic combustion of wood, alone or combined with other fuels like
coal, as alternatives to imported oil and gas fuels are increasingly
sought.
^hile regulation of combustion sources of home heating in Europe
has taken diverse forms, the central focus had been on residential
equipment cesign, installation, operating and maintenance. Most
Lurojean countries have re9ulations requiring inspection and maintenance
of oloc.s and central district scale neatiny equipment, at least once
a year by professional chimney sweeps. These inspections typically
check not only pollutant emissions, but also safety and efficiency
factors; and clean and adjust the equips.;ent and chimney for optimum
rierforniance. Such inspection and maintenance is not typically required
for residential scale equipment except under local nuisance procedures
when complaints are received. Solid fuel fired residential scale equip-
ment is often unregulated, although there is growing interest in it,
as wood and coal fuel becomes increasingly attractive.
For example, in West Germany federal law requires that residential
scale heating devices fired with solid fuels must either: 1) use smoke-
less (low smoke) fuels; or 2) be designed like a Universal-Dauerbrenner
(slow combustion) stove, which achieves more complete combustion of
volatiles during a down draft design, which forces volatiles to pass
through a flame zone before exiting from the burner. Inspection of
residential scale solid fuel-fired heating equipment is not required
unless complaints exist. Larger (block or central district heating)
equipment must be inspected by the district chimney sv/eep once a year,
including an emission test measurement. For some of the larger equip-
ment, specific participate emission standards exist.
In Switzerland, no federal environmental protection law exists,
so legal enforcement of emissions limits only could be done through
nuisance complaints. No emission standards exist for solid fuel fired
equipment. A federal guideline prohibits trash burning in fireplaces,
and recommends burning dry wood only. Fire insurance companies require
testing of any heating appliance, mostly for safety factors. However,
II-5
-------
carbon monoxide emissions are limited to ll,» by volume for solid fuel
firea equipment. Larger central heating plants ;.iust nave annual inspec-
tion and maintenance by chimney sweeps. Austria, like Switzerland,
has relied on required maintenance of larger heating 'equipment rather
than emissions standards.
In Sv.eden a large increase in r
-------
less negative impact on air quality in urban and suburban areas, by
taking advantage of the fact that fewer large fuel combustion systems
can be operated more efficiently and far more cleanly than many small
ones in individual homes. Pollution control equipment can be applied
to the larger units with economies of scale not possible for individual
horv.e units.
jeniiiark has limited wood available for RWC and to stoncaro's for
-.'oocS combustion equipment.
France has abundant forest resources, and great potential for
expanding its use of wood as a fuel. France has not regulated domestic
",ol: , riiel combustion, except for a few local proni j:: ions of v;ooa
jr cc..-;] use in clean air zones of some of its larger cities. Fire
insurance companies in Paris increase premiums up to three fold for
failure to provide evidence of annual inspection and maintenance.
D. ROCKY MOUNTAIN REGION, U.S'.A.ld
Several Colorado mountain communities (Vail, Aspen, Telluride,
Steamboat Springs) were concerned that increasing tourism, in which
they were economically interested, would worsen already aeclimng air
quality, primarily due to increased fireplace use and automobile
traffic. For example, the following control measures were implemented
in Vail, Colorado:
-Public education - how to burn cleanly
Voluntary curtailment of RWC and driving is requested when CO or
TSP exceed specified levels
Hew homes, hotels, and restaurants are prohibited from installing
more than one stove or fireplace
Coal sale or use is banned in the city limits (although not in the
surrounding county were most growth is occurring).
Devices to improve fireplace efficiency (e.g., excess air)
are required
The City Engineer may establish design standards for RWC equipment.
II-7
-------
The city of Missoula, Montana, located In one of the poorest
ventilated areas in the country, has high RWC activity levels and
violations of federal CO and TSP ambient air quality standards. RWC
was confirmed to be a major source. As a result, citizen committees
1P
rccoir.(;,endec the follovmig Rv.'C control measures in 1921:
I'jui i-c tuuciit ion on potential R^C ifiipacts
Voluntary curtailment of RWC and driving requested by media "alert",
3 3
when TSP exceeds 150 yg/m (or 60 yg/m of respirable particulates).
As of January 1982, mandatory curtailment of wood burning
3
when TSP exceeds 300 yg/m on an 8-hour basis (since adopted).
Establish emission standards for RWC equipment in new construction.
Technical problems may preclude implementation of some of those
recommendations. The cost/benefit ratio of training srnoke readers
to conduct opacity tests, or of establishing and enforcing emissions
standards, is questioned by EPA. EPA contends that it lacks authority
under the Clean Air Act to establish national emission standards for
RWC equipment, similar to those proposed by the Missoula citizens
committee, and that such standards may succeed only in promoting dis-
tributors to sell their equipment elsewhere, rather than to improve
it. To the extent that EPA lacks the authority, or desire to regulate
RUC, the most likely areas for development of RwC controls will be
communities like Missoula, Montana or Medford, Oregon, which experi-
ence major RWC impacts, usually because of high RWC levels and
unfavorable meteorological or topographical conditions for pollutant
dispersal. Local community emissions or ambient standards would not
be precluded, even where state law exempts residential heating from
pollution control regulation by state agencies.
11-8
-------
c..
MLb'r wuLJ, Ji\EGOii
liedford, Oregon also Is situated in a mountain valley with atmos-
pheric inversions similar to Missoula, Montana in its capacity to trap
and concentrate air pollutant emissions. Studies by the Oregon Depart-
ment of Znvi ronniental Quality (DtQ) have used chemical fr.ass balance
o i.'eesure respirable particulate and have measured in,pacts
of as high as 02 us/in" during poor winter ventilation periods.
Annual average impacts of 20.o yg/m of respirable particulate from
RWC ',;erc- recorded in downtown Bedford for a July 1979 - June 1980
period. This accounted for 29:i of all locally generated total par-
ticulatt: and oo'i of all locally generated (i.e., corrected for back-
ground levels) respirable particulate. It is clearly the major par-
ticulate source impacting the Medford area, which currently violates
primary (health related) particulate standards.
The Jackson County Commission with planning jurisdiction for
the entire valley containing Medford and nearby smaller towns, recently
2
adopted the following RWC control strategy , aimed at eliminating
primary standard violations by July 1984:
Firewood Moisture Control - through public education about seasoning
wood; and encouraging spring firewood cutting at nearby national
forests, through incentives to individuals and commercial cutters.
i.eatherization - required, to minimum cost effective levels, to
install a new wood stove. A voluntary goal was set to weatherize
all households in the air quality planning area by July 1984, with
financial incentives including low interest loans, tax credits and
help from utilities. If the primary particulate standard is not
met by July 1984, the County will make weatherization mandatory.
Episode Controls - Voluntary curtailment of RWC during Air Stagnation
Advisories, unless there is no alternative heat source. Mandatory
curtailment if TSP exceeds the primary standard (260 yg/m ), or during
Air Stagnation Advisories, if standard is not met by July 1984.
II-9
-------
Proper Sizing of .lew ';
-------
have celayed payback requirements, .'.ost utility loan: :,rt- available
only to their customers.
The City of Portland adopted in 1979 an Energy Policy which
requires that all residences be insulated to cost effective levels
prior to resale, starting in 1984. Low interest (3C'; loans are avail-
able. "Cost effective" is cefined as total coses of '.,-eothen zation
and fuel should not exceed fuel costs without ,,
-------
T T
i 1
I. A CONTROL STRATEGY EVALUATION PROCESS
A. THE KEPPi'lER-TREGOE EVALUATION PROCESS
This section describes how the Keppner-Tregoe decision analysis
Q i.
process was adapted to evaluate proposed RwC control strategy ele-
,i,er;ts or final control strategies, and to rank tlieiii in tenis of their
overall satisfaction of multiple criteria. This process involved the
following steps:
i. :.^'-'j]^s^. ',,i '!,.. u;.i require..ients (I1JST criteria;, ,::: '.., anj
^rCjjuScd /,,,C control strategy inust ;,ieei to receive fjrtner
consideration.
2. Establish desirable requirements (WANT criteria), which make
any proposed strategy more effective or acceptable.
3. Determine the relative importance of the WANT criteria in
evaluating strategies (Weighting Factors).
4. Evaluate proposed strategies using MUST and WANT criteria,
in two steps. First, screen out strategies which do not
satisfy all MUST criteria. Second, for remaining strategies
generate a numerical score by evaluating how well each
strategy satisfies each WANT criteria. Use scores to
tentatively rank all feasible strategies.
5. Review strategies to identify important adverse consequences
of implementing them. If these consequences are serious
enough, make changes in the overall ranking of strategies.
6. Separately estimate the costs and benefits of each strategy,
to both the private and public sectors.
7. Display the final strategy rankings, costs, and benefits
in matrix format.
III-l
-------
L. 5£LiiCTlLi!-; Ul- MUSI A.'JD UAi'iT u'.ITLilln
In establishing MUST and WANT criteria, the following considera-
tions were paramount:
1. Proposed K,,'C control strategies must be effective in reducing,
air pollutant emissions froi., R',.'C activity. This is the first
priori ty.
2. Strategies also must:
a. Meet Clean Air Act and ZPA requirements.
b. Conform to and support State Implementation Plan (SIP)
strategies.
c. 3e widely applicable to RWC appliances or practices.
d. Be implementable within a reasonable time (preferably
within a few years).
e. Not worsen safety characteristics of using RWC to heat
homes.
3. Strategies also should, to the maximum extent possible:
a. Be technically sound.
b. Be administratively feasible.
c. Be acceptable to the public.
d. Help the RWC appliance industry to itself encourage manu-
facture of cleaner burning devices.
e. Cost parties affected as little as possible.
Tables 1 and 2 summarize the MUST and WANT criteria selected
for use in evaluating proposed RWC control strategies. Appendix D
describes the rationale for selecting these particular MUST and WANT
criteria. The items listed under most WANT criteria help explain their
intent, and help apply them in scoring strategies.
III-2
-------
riUST Criteria
1. Reduce RWC air pollution impacts.
2. Meet all legal requirements established by the Clean Air Act, EPA,
or State regulations, State Implementation Plans, or local
orcinances.
3. Le widely applicable to HUC appliances and/or practices, or be
particularly effective for a significant category of RWC appliances
or practices.
iditstair, safety faci',r~. '.>? ''.,.C.
d. ic fully ii.ipler.ientavj 1 -_ ,.,;':;!: tiie next five years ... unless
'sionificant benefits car; i/e realized over a longer time frame.
III-3
-------
TABLE 2
WANT Criteria
1. Reduce the average air pollution (mainly particulate) emissions per
household from RWC.
2. Reduce the number of households using RWC.
3. Widely applicable.
4. Maximum public acceptance.
-- Minimum hassle to individual (not cpst)
-- Acceptable level of regulation (i.e., restriction of personal
freedom of choice)
-- General acceptability to various interests
-- Preferably, significant support
5. Discourage use of most polluting RWC appliances/practices.
-- Financial disincentives to manufacturers of dirty devices
(emissions tax)
Disincentives for poor RWC practices - create stigma, through
media campaign, attached to poor RWC practices ("litterbug"
analogy)
6. Minimize cost to individual consumers.
-- Capital and operating costs of RWC appliances
-- Private sector costs, since these will be passed on to consumers
-- Fuel costs
-- Financial Incentives - pollution tax credits, rebates, etc.
7. Utilize proven technology.
-- Technology demonstrated in practice; minimum research and
development needed to implement strategy
-- Low maintenance and repairs needed
8. Minimum probability of circumvention.
-- Technology based improvements are more guaranteed
-- Behavior based improvements are less certain
II1-4
-------
TABLE 2 (Cont.)
9. Maximum administrative feasibility for regulatory agencies.
-- Minimum agency cost to regulate RWC
-- Implementation ASAP (within 3-5 years)
-- Documentable RWC emissions reduction, for SIP purposes
-- Conform to Clean Air Act, EPA requirements
-- Acceptable to regulated parties
-- Other key actors willing to participate
10. Encourage innovative technology.
11. Minimize interference in free markets.
-- Maximum self regulation by RWC appliance manufacturers,
retailers,, etc.
*
-- Regulatory policies which try to exert their effect through
free market forces, or incentives, will be preferred
12. Promote energy conservation and use of renewable energy resources
(excluding promotion of wood fuel for RWC).
III-5
-------
C. l.'EIkHTIiJG FACTORS FOR V.ANT CRITERIA
To represent the relative importance assigned in this evaluation
to each WANT criteria, a Weighting Factor was developed for each
criteria. An analytical tool called paired comparison was used for
this purpose. Trie resulting height Factors assigned to the twelve
" -'<" -'"" - "!"- i:.j',.'fi ' n rigure 1. Appendix j expUnns no- chese
were arrived at. Some cf ch^se uAi'iT criteria and tneir weignt ing induce
the follow ing:
1. Criteria which significantly reduce air pollution
fro!.. ,",«'C are more important than criteria, whicn are only
;;,eans to this end. For example, "reducing RUC emissions/
household" is directly effective in reducing RWC air pollution
impacts. "Use of proven technology" is desirable, but does
not guarantee that a strategy will reduce RWC pollutant
emissions.
2. The mo*st desirable characteristic of a RWC control strategy
is that it reduces average emissions per household. This
is a more desirable approach, than reducing the number of
RWC households, although both are very effective in reducing
RUC pollution impacts. Strategies designed to discourage
household use of RWC could be more unpopular, and might unduly
limit individual freedom of choice. A widely applicable
strategy which reduces average household emissions could
improve air quality more than one which discouraged a rela-
tively small portion of households from using RWC.
3. To effectively combat RWC pollution, it is more important
that a strategy be widely applicable to RWC appliances, or
practices, than low in consumer costs, although both are
very important. Wide applicability multiplies any strategy's
effectiveness in reducing pollution. Low consumer costs
are a strong influence on whether people purchase and continue
III-6
-------
to use ,,UOG burning appliances, but not all strategies affect
appliances, and low price cannot guarantee installation of
improved technology.
4. Public acceptance of regulation of RWC, and any extra incon-
venience it brings, is very important for an area-wide air
pollutant source like Ri.'C. Members of the public .-.'ho operate
these sources can often choose to cooperate or thwart control
strategies, as illustrated by public attitudes ana actions
with r-jspect to vehicle inspections.
:. USE JF . I,:T >_, .,<:. T C,
-------
FIGURE 1
. Application of MUST and WANT Criteria to Evaluate and Rank RWC Strategies
1.
2.
3.
4.
5.
MUST Criteria
Reduce RWC Air Pollution
Impacts
Meet Legal Requirements
Widely applicable to RWC
appliances or practices
Maintain RWC Safety Factors
Implementable within 5 years,
unless long term benefits
great.
WANT Criteria Weight
Factor
Strategy A
Go /No Go
Go
Go
Go
Go
Go
Rating "TD
b Score
Strategy B
Go /No Go
Go
Go
Go
Go
Go
Rating CWTD
3 Score
Strategy C
Go /No Go
Go
Go
Go
Go
Go
Rating CW1D
3 Score
Strategy D
Go /No Go
Go
Go
Go
Go
Go
Rating ,WTD
Score
1
10
11
12
13
Reduce Ave. RWC
emissions per house-
hold
Reduce No. of RWC House-
holds
Widely applicable
Maximum public accept-
ance
Discourage worst ap-
pliances, practices
Minimum consumer cost
Use proven technology
Minimize Circumvention
Maximum agency admin.
feasibility
Encourage Innovative 2 5
Technology
Minimum free market 2 2
interference
Promote conservation re- i Q
newable resources (except
wood for RWC)
WANT Criteria Scores:
Adverse Consequences Scores (Risk Factors):
13
10
9
6
5
4
3
10
9
4
10
117
117
80
54
36
60
45
16.
30
10
4
0
563
36
52
10 130
4
9
40
81
72
7
10
4
7
5
7
7
42
50
16
21
10
14
7
9
7
10
9
4
7
5
8
6
514
120
117
104
90'
63
45
60
45
16
21
10
16
6
b93
160
-------
In the third step, potential problems of iri;p ler.ientation or adverse
consequences of fully implementing a strategy are identified. An
"adverse consequence score" or Risk Factor is generated by estimating
on a scale of 1-10 both the likelihood of occurrence, and the serious-
ness of the adverse impact. These two numbers are multiplied to provide
a score, and the scores are summed to provide a "is". Factor for each
strategy as shown in Figure 2. Then these Risk Factor scores are
entered in Figure 1 for comparison with '.-jAul criteria scores.
/.'ANT criteria scores then are compared with the adverse conse-
quences scores to determine if the preliminary ra^in.. of control stra-
t'-, i :-s 5r,OLjlc: be c/'angea. Adverse consequences ^ci rt-_ >..re not suo-
cracce^ rrc,,. trie scores based on satisfaction of ..."...Is. ,
-------
FIGURE 2
Assessment of Possible Adverse Conequences of Strategy Implementation, or Risk Factors
Strategy A
1. Significant opposition by environmentalists
Probabi1ity of
Occurrence (P)
9
Seriousness Risk Factor
of Impact (S) (P x S)
4 36-
Adverse Consequences Score (Risk Factor)
36
Strategy C
1. Key strategy participants unreliable (lending institutions) due
to high interest rates
2. Public acceptance questionable because it restricts freedom
to sell home
Adverse Consequences Score (Risk Factor)
56
64
120
Strategy D
1. Results very difficult to document
2. Significant opposition by wood stove manufacturers
10
9
7
10
70
90
Adverse Consequences Score (Risk Factor)
160
P = Probability of Occurrence (1 to 10)
S = Seriousness of Impact (1 to 10)
P x S = Risk Factors
10 x 10 = Unavoidable Disaster
-------
C'jjt.3, out rather bcr.us achievements from implementing a control
strategy, in acdicion to pollution abatement. An example v.'ould be
energy conserved by weatherization of homes, or reduced danger of home
fires (increased safety) due to reduced creosote formation in stove
f1ues.
The types of costs considered included: l)public sector: agency
costs :c i ,..! e:;:enr a strategy; public costs to comply with regulatory
requirements, or increasec consumer costs for wood burning caused by
strategies; and 2) private sector: costs to comply with regulatory
requirements, or to take advantage of incentives or meet competition
>:ausec- ny strategies. These cost estimates ere admittedly crude, out
their assumptions ana uncertainties are spelled out, as much as
possible. They also were based where possible on the experience of
established control programs.
F. MATRIX SUMMARY OF RESULTS
The resulting ranking of control strategies versus WANT criteria
may be displayed in a matrix format such as Figure 6 in Section VI
of this report, along with highlights of the costs and benefits of
implementation.
III-ll
-------
-------
SELECTION AND EVALUATION OF INITIAL RUC CONTROL STRATEGY ELEMENTS
This section describes the identification and evaluation of a
comprehensive list of RWC Control Strategy elements - e.g., single
actions which can directly or indirectly help to abate air pollution
fro.!- residential wood combustion |RUC). These elements were dravvn
rVu.u approaches, re^uluiury programs, devices ur incentives that have
Deen inipler.ientec or considered around the world to control RWC pollution,
Original ideas for which no precedent was found also are included.
No plausible idea was eliminated at this stage, no matter how
..j:c-nn al ly costly or difficult it might appear, unless it was simply
not widely applicable in controlling wood burning appliances. Consis-
tent with the overall, technical approach (Section IB) the identification
here of individual RWC control strategy elements for initial explora-
tion is intended to be comprehensive. These strategy elements then
are evaluated using an abbreviated (two-step) Keppner-Tregoe process
to determine which best satisfy the MUST and WANT criteria described
in Section III. A complete ranking of all control strategy elements
considered, based on WANT criteria scores, is presented. The reasons
why certain eleme'nts rank higher than others is discussed.
Over seventy-five individual control strategy elements are
identified and evaluated in this section. These were grouped as follows
to facilitate their evaluation and to emphasize essential features
or distinctions.
Strategies to reduce RWC emissions by improved burning equip-
ment design.
A. By regulation
3. By market incentives, or disincentives
C. By information distributed, or technology transfer
Strategies to reduce RWC emissions by reducing wood usage.
A. By regulation
3. By market incentives, or disincentives
C. By information distribution, or technology transfer
IV-1
-------
Strategies to reduce RWC emissions by improving operatic.,
procedures of wood burning equipment.
A. By regulation
B. By market incentives, or disincentives
B. By information distribution, or technology transfer
-.. I:E,>:TIF;CAT;,.\ ..p POTENTIAL R;;C CONTROL STRATEGY ELEMENTS
Appendix A contains the comprehensive list of potential R'*C con-
trol strategy elements identified, grouped into the categories listed
above. All seventy-five control strategy elements in Appendix A far<
into one of the-3eneral categories of RWC emissions controls listec
below. These were gleaned from literature sources, personal contacts,
and our own considerations of RWC emissions control problems and
possibi1ities.
Weatherization of homes. Reduces space heating requirements.
Assumed to reduce RWC emissions by allowing less burning to main-
tain adequate heating.
Standardized Emissions Testing of RWC Equipment. Allows objective
comparison of burning equipment performance. Provides information
. basis for consumer choice and feedback to manufacturers to
encourage improved performance. Provides basis for emissions
standards, and regulations to encourage or require cleaner
burning units.
Wood Fuel Moisture Content Controls. Seasoned (dry) wood burns
cleaner under most circumstances.
Episode Controls. Voluntary or mandatory curtailment of RWC
: "" - - ^
during air stagnations.
Sizing of Burning Equipment to Space to be Heated. Selecting
minimum adequate size minimizes emissions, by minimizing charge
, size and maximizing burning rate per volume charged.
IV-2
-------
in.ission Density Zoning. Limiting the aincun". of '.(', in 3i.r
e,oality problem areas.
Periodic Inspection of Installed RUC Equipment.
* Limiting Firewood Supply.
Promotion of Alternatives to RWC. For example, solar, or other
radiant heating appliances, even conventional fuels (oil, gas,
electricity); or personal insulation I wanner cloths,.
Economic Incentives or Disincentives, or i'ub'nc information.
Designed to educate people about RWC and to pro,note less
polluting RWC.
Research - to Develop Cleaner RUC Equipment or Practices.
u. EVALUATION OF CONTROL STRATEGY ELEMENTS
*
The Keppner-Tregoe evaluation process described in Section III
was applied to the list of RWC control strategy elements in Appendix
A, in an abbreviated (two-step) form. That is, strategy elements were
evaluated against MUST and WANT criteria, but risk factors related
to adverse consquences of implementation were not considered. Risk
factors will be considered in evaluating final RUC strategies (Section
VI). They should be more meaningful in evaluating final strategies
consisting of a combination of strategy elements, because some elements
may be employed specifically to mitigate adverse consequences of other
elements.
Appendix 3 contains the seventy-five strategy elements listed
in order of their scores based on satisfaction of-all twelve WANT
criteria. It also contains a table showing the individual scores
assigned to each strategy element for each WANT criteria.
The ranking of all strategy elements against all WANT criteria is
summarized in Tables 3, 4, and 5 and discussed below. These three tables
show the relative ranking of A, B, and C Type control strategy elements,
which correspond, respectively, to regulatory actions, market incentives/
disincentives, and public information/technology transfer approaches,
IV-3
-------
TABLE 3
Entry
Ranking of RWC Control Strategy Elements
vs
WANT Criteria - Regulatory Actions
Overall
1
RankScore I.D. No.
Description of RWC Control Strategy
10
11
535
III.A.3
2
3
4
5
6
7
8
9
2
3
4
5
6
7
15
16
504
487
480
476
471
469
424
422
II. A.I. a
I. A.I. a
II.A.l.b
II.A.l.d
II.A.l.c
I.A.l.b
I. A, 2
III. A. 4. a
17 418 III.A.I.a
385 III.A.a.b.c.d
18 416 II.A.2.b.3
Government requires manufacturer to
label stove as space it will heat vs
various home insulation levels.
Allow new stoves only in highly
weatherized households.
Government Acquires certification of
new stoves vs emissions standards.
Government requires weatherization to
cost effective levels within 5 years
or after resale.
Government requires utilities to
help pay for weatherizing households.
Government requires industry to help
pay for weatherizing households.
Government requires replacement of
existing stoves with certified low-
emitting units.
Government required rating of burning
units for emissions, to allow sale.
Government requires commercial wood
sales to include information on
moisture content levels.
Chimney sweeps test household emissions,
Reduce/eliminate fall firewood cutting
on federal lands to increase chance of
proper drying.
From Table Cl, Appendix C
2 From Table Bl, Appendix B
IV-4
-------
Entry
Overall
Rank Score I.D. No.'
Description of RWC Control
12
13
14
15
16
17
19 415 II.A.A.b
20
51
407 II.A.4.a
32 360 II.A.3.a
342 II.A.2.b.2
35 359 II.A.2.b.l
347 II.A.2.b.2
48 273 II.A.2
252 II.A.2.a
Allow new burning unit only if certain
efficiency standards met.
Allow new burning unit only if it
provides a substantial net heat gain.
Emission Density Zoning - allow only
X wood burners per (mile)^ based on
pollutant dispersion capacity.
Firewood cutting on federal lands
limited based on air quality levels.
RWC cutbacks during air pollution
episodes.
Require USFS/BLM ,EIS to assess air
quality effects of their firewood
releases.
From Table Cl, Appendix C
From Table Bl, Appendix B
IV-5
-------
TABLE 4
Ranking of RWC Control Strategy Elements
vs
WANT Criteria - Market Incentives/Disincentives
Fnt p >/
L y Rank
1 10
11
2 12
3 14
4 21
5 23
6 26
7 36
8 38
9 42
10 43
11 47
12 49
13 53
Overal
Score
459
453
447
436
404
401
392
394
394
363
345
326
310
304
283
271
273
234
225
I1 2
I.D. No.
I. B.I. a. 4
I. B.I. a. 3
I.B.l.c
I.B.l.b
II.B.l.b
I. B.I. a. 1
I. B.I. a. 2
II.B.4.5
II.B.4.C
II. B. 4
I.B.l.b.Z.b
I.B.l.b.l.a
III.B
II. B.I. a
II.B.2.3
II.B.2.b
II.B.A.d
II.B.S.b
II.B.S.a
Description of RWC Control Strategy
Consumer subsidy to buy cleaner
burning combustion equipment.
Government sponsored $50,000 prize
to designer of first burning unit
to cost <$1000 and emit <1 g/kg. .
Tax disadvantage to companies pro-
portional to the emissions levels
of their burning units.
Government subsidizes weatherization
in all areas.
Government subsidizes purchase of
cleaner new burning unit.
Lower residential rates for gas/oil.
"Lifeline" electricity rates.
Government subsidy to manufacturers
of burning units for pollution
measuring equipment.
Government subsidizes regional wood
drying facility.
Government subsidizes weatherization
only in areas with severe pollution
potential .
Increase wood prices to decrease
RWC by greater residue utilization
Increase wood prices by raising
cutting fees.
Subsidize solar energy as RWC altern,
Increase RWC cost by encouraging fin
insurance increases or property tax
increases for RWC users.
From Table Cl, Appendix C
From Table Bl, Appendix B
IV-6
-------
10
11
TABLE 5
Ranking of RWC Control Strategy Elements
vs
WANT Criteria - Public Information/Technology Transfer
l-"l"J Rank
1 8
2 9
3 13
4 22
5 24
6 25
7 27
8 28
9 29
Score
468
465
437
403
395
396
387
380
383
390
364
364
358
I.D. No.
III. C. 3. a
III.C.3.b
I.C.2.b
I.C.Z.c
II. C. 2
I. C.I. a
II. C. l.c
II. C.I. a
Il.C.l.b
Ill.C.l.b
III. C.I. a
I.C. 3. a
I.C. 3. a
I.C.S.b
t^t owi i p u j u* M \j i i\n v uwiic-iwi .j u i a L. t; y jf
Government distributes information
on proper stove sizing.
Trade Association develops rating
program for how much space can be
heated by a given unit (sizing).
Mandatory emissions testing of
burning units by Trade Association.
Make public aware of true wood
heating costs.
Government provides free fully-
staffed emissions testing facility.
Disseminate information on burning
unit efficiency by neutral organization,
government, or trade association.
Educate wood users as to moisture
content effects on emissions and
efficiency.
Government sponsors $50,000 prize for
first test procedure system costing
less than $100/test.
Publish information on burning unit
design considerations/research ...
31
33
360
I.C.2.a
359 I.C.l.b
government or trade association.
Voluntary Trade Association emissions
rating program.
Government tax credits on equipment or
service for emissions testing of
burning units.
From Table Cl, Appendix C
From Table Bl, Appendix B
IV-7
-------
Entry
12
13
14
15
16
17
18
uver
Rank Score
34 357
39 341
331
40 335
41 315
44 298
45 293
46 285
283
275
a"
I.D. No.*
I.C.l.c
III.C.2.a,d,e
III.C.2.b,c
II. C. 4
IH.C.l.d
II. C. 3
II.C.6.a
Il.C.S.a
II.C.5.C
II.C.B.b
Description of RWC Control Strategy
Government funds development of
standardized, simpler, cheaper
emissions test procedures for RWC
units .
Distribute information on avoiding
creosote buildup/minimizing emissions
... by government or trade association
Make public aware of frequency of
fires 'associated with RWC, to
discourage use.
Distribute free moisture meters to
commercial wood distributors.
Make public aware of health concerns
related to indoor air pollution
from RWC.
Promote personal insulation - wearing
warmer clothes indoors to reduce
heating needs.
Promote alternative radiant heat
sources - e.g., natural gas fire-
places, passive solar, gas heaters.
19
20
21
50
52
54
264
235
211
II.C.6.b
III.C.4
II.C.2
Promote personal insula-tion - spot
heating of key areas in house.
Concerned neighbor approach - neighbors
tell others how to reduce RWC emissions
Suggest households limit annual fire-
place usage,to 10 occasions to reduce
heat loss.
From Table Cl, Appendix C
From Table Bl, Appendix B.
IV-8
-------
respectively. This allows these .three .;rajor methods of achieving RWC
controls to be considered separately. However, the "overall rank",
among all seventy-five strategy elements, also is shown in column two
of each table. Note that for simplicity, when similar strategy elements
ranked close together, they were combined in the final list (in
Appendix £). Thus, this final list contains 54 ranks into which the
75 strategy elements were grouped.
It is important to keep in irnnd that the numerical scores and
resulting rankings are merely a device to aid in evaluating a large
group of possible strategy elements. The absolute scores are less
important than the relative ranking of strategy elements. It also
is important to remember that the ranking represents the relative degree
to which all WANT criteria are satisfied, simultaneously, by a given
strategy element.
Top ranking strategy elements are not necessarily those deemed
most able to reduce RWC emissions, although they likely scored well
on this criteria. Top ranked strategy elements represent the best
overall rating, taking into account not-only emissions control, but
also other key attributes such as wide applicability, public acceptance,
consumer cost, administrative feasibility, etc..
The degree of subjectivity inherent in this evaluation process
also should be recognized. It can strongly reflect the views and bias
of trie analyst, however unintended. The assignment of scores for
satisfying WANT criteria, and even the relative weighting of WANT
criteria, involves personal judgements by the analyst. No two analysts
attempting this task would produce identical results, and some might
produce widely varying results. Nevertheless, this Keppner-Tregoe
process provides a systematic (if laborious) way to evaluate a large
number of possible choices against a list of weighted decision criteria
to achieve a relative ranking of the choices. The results can be
analyzed as to why certain choices ranked higher and others low. This
is done in subsection B2 below for the strategy elements shown in
Tables 3, 4, and 5. Prior tt) that, however, key considerations, in
IV-9
-------
assigning w'AiJT criteria satisfaction scores are discussed in
subsection 1, below.
1. Assigning WANT Criteria Scores
The judgements made in the assignment of scores for satis-
faction of ;:ANT criteria has ar obvious anc direct influence
on the eventual ranking o~" control s'-.^ategy jlaments. To under-
take this scoring effort systematically, and to assure consistency
among scores, required establishing at least a rough decision
framework for scoring for each WANT criteria. This decision
framework, and judgements and assumptions used in scoring, can
ouild biases into the scoring process ,/hich nelp determine and
explain the resulting ranking of control strategies. Care must
be taken to minimize such bias.
To help systematize scoring the following general decision
framework was used for each WANT criteria:
Each control strategy element was to be assigned a score
from 1.-10 based on the degree to which it satisfied a given WANT
criteria. For each WANT criteria, five satisfaction levels were
described as illustrated in Table 6 for WANT criteria T?4 (maximize
public acceptance). Each represented a scoring range of several
possible total points.
All RWC control strategy elements were assigned to one
of the satisfaction levels, and assigned a score within its range
of possible points. To further assure consistency in scoring
a preliminary identification of the highest and lowest scoring
strategy elements was made, so that scores for the rest would
fall in appropriate intermediate ranges. Also, similar strategy
elements were assigned similar scores.
Appendix B (Table 82) contains the scores assigned to each
strategy element, for each WANT criteria, and which resulted
in the rankings in Tables 3, 4, and 5.
IV-10
-------
5
General Satisfaction Levels for KANT Criteria £4 -
"Maximum Public Acceptance"
Satisfaction
Level
Possiole
/cir.ts
Criteria for satisfying tc this level
i-lC
Moderately
Poorly
None
3-4
0-2
Fully acceptable; some significant support
no significant oppositon.
Acceptable to uiost par;,ies; soi.c-
support; nc significant Apposition.
Lukewarm acceptance; most people
don't know or care; or, offsetting
support and opposition.
Acceptable primarily to environ-
mentalists; average person wary or
opposes.
Not acceptable to many;
strong opposition.
IV-11
-------
2 . Discussion of Resulting Ranking of Control Strategy Elements
Comparison of Tables 3, 4, and 5 indicates that regulatory
actions tended to rank higher than market incentives/disincentives
and both tended to rank higher than public information/technology
transfer approaches, as RWC control measures. Analysis of
individual scores (Appendix 8, Table Z2] indicates this is due
;:;, c itnJency for regulatory approaches to score higher in the
ir.ore heavily weighted WANT criteria, e.g., reducing household
RVJC emissions (#1), wide applicability (#3), discouraging worst
appliances (#5). Similarly public information/technology transfer
approaches tended to score low in these areas.
This also makes common sense, in that the success of a
control strategy element often seems more assured under regulatory
pressures than under reliance upon voluntary actions, or based
on public information about the strategy. There is less choice
under regulatory approaches. People tend to obey the law, even
if they dislike it. Regulatory approaches also depend less on
an informed public, Regulations seek out affected parties and
regulate some aspect of their actions. The success of approaches
based on incentives or public information depend first on whether
affected parties even know about them, and second on whether they
choose to act in the manner intended by the strategy.
Looking at the three tables individually, the following
strategy approaches received consistently higher scores:
Proper sizing of wood burning units (A, C)
Emissions testing and certification of wood burning units
Weatherization of homes
Regulatory efforts or subsidies to encourage development
and use of cleaner burning units
iJood moisture content controls
IV-12
-------
Tn& fcliowinc, types of approaches received consistently lower
ranki nc,s:
Limit RWC, by restricting
- v/ood supply
- burning in air quality problem areas
leven uur^nb episodes, surprisingly)
Li HI if me, ;;.,x oy increasing costs of
- firewood
- fire insurance for RWC homes
Promoting alternative ',ieat",ng sources, suci~ as solar, or
radiant gas heaters
Promoting personal actions, such as dressing more warmly
at home, voluntarily limiting RWC, or advising neighbors
how to burn more cleanly
Many of the higher scoring control strategy elements were
incorporated into one or more of the final RWC control strategies
evaluated in Section V.
IV-13
-------
-------
V. GENERIC APPROACHES TO REDUCING RUC EMISSIONS -
;L/MITITATIV: ESTIMATES OF Ef-'.ISSION REDUCTIONS ACHIEVADLE
This section discusses the following generic strategy approaches
to reducing Rl.'C particulate emissions:
Improving ourning Unit Design
1. Improved design of new stoves
a. Testing of wood stoves/furnaces, and certification
'of compliance with an established emission lii,.it,
as a prerequisite for allowed sales
j. Testin^/certification as a prerequisite uf sLov',-
furnace sales, plus a financial incentive i33-. tax
credit) to buy the cleaner (certified) stoves
c. Testing/certification as a basis for mandatory
labelling of all stoves/furnaces sold, which specifies
their efficiency and emissions performance
d. Testing/certification as a basis for mandatory
labelling, plus the 33% tax credit for clean units
2. Modification of installed stoves/furnaces, including:
a. Air inlet modifications
b. Insertion of firebrick in stove box
c. Fans to improve heat transfer
d. Add-on particulate control devices:
1. Steel wool mesh filter
2. Catalytic afterburner
3. Improved design or add-on devices for fireplaces
a. Underfire air
b. Electrostatic precipitator
c. Glass doors
B. Reducing Wood Usage
1. Reducing home heating requirements
a. Weatherization
b. Reducing stove charge size
, 2. Improving wood fuel quality
a. Selection of wood with higher heating value
b. Moisture control (seasoning)
V-l
-------
J. Direct restrictions of wood usage
a. Lfjisoce controls
b. Emission density zoning
C. Improving RUC Operating Practices
1. Initial selection of burning units - sizing
2. Operating technique modifications
a. Discouraging airtight stove operation
b. Charging larger pieces of wood
3. Periodic inspection of RWC equipment
This section also estimates the potential ability of these stra-
tegy approaches to reduce RUC emissions (primarily particulate emis-
sions, including volatile organics). These quantitative estimates
of emissions reduction potential are summarized in Table 7 and docu-
mented in more detail in Appendix D. These estimates are largely
speculative, because little exists in the way of quantified experience
in controlling RWC as a pollution source. For example, there is still
much to learn about how to control the combustion process within stoves
and fireplaces to burn most efficiently and cleanly (emissions).
The approaches discussed here for reducing RWC air pollution also
could be implemented using a variety of means, which could be
summarized in the following categories:
1. Regulatory actions or requirements
2. Subsidies or market incentives
3. Information distribution or technology transfer
The many possible combinations of strategy approaches and implementa-
tion means are too numerous to examine individually regarding their
potential for reducing RWC emissions. (Section IV examines and ranks
a large number of such individual strategy elements using selected
criteria.) However, examples of all three categories of implementation
methods are included in the strategy approaches analyzed in this
section, as well as in the final strategies evaluated in Section VI
of this report.
V-2
-------
TABLE 7
Comparison of Estimated Particulate Emission Reductions
Achievable by Generic RWC Control Strategy Approaches
Generic RHC Emissions Control Strategy Approach
A. Improving Burning Unit Design
1. Promotion of design and use of cleaner new
stoves/furnaces
a. Testing/certification as prerequisite to
sales or installation.
b. Test/certification as prerequisite to
sales, plus $400 (33%) tax credit.
c. Testing/certification as basis for mandatory
labeling prior to sales,specifying efficiency
and emissions performance.
d. Testing/certification/label ing, plus $400
(33%) tax credit.
Modifications of installed stoves
a. Air inlet modifications.
b. Insertion of firebrick in stove box.
c. Heat transfer improvement (fans).
d. Add-on Particulate control devices
Improved design or add-on devices for fireplaces
a. Underfire air.
b. Electrostatic precipitator.
c. Glass doors.
A.
Potential Particulate Emissions Reductions
Improving Burning Unit Design
la.
Ib.
1985
2
y
YEAR
1990
8
11
1995
22
30
2000
30
39
Ic.
Id.
2a.
2b.
2c.
2d.
1 5 15
(Table D3 values X .7)
11
21
No basis for emission reduction credits
No basis for emission reduction credits,
Negligible (0-1%)
Negligible (G-1%)
3a. 1% by 1990; 2% by 2000.
3b. 46% (single test); expensive ($1,400).
3c. No basis for emission reduction credits.
V-3
-------
TABLE 7 (Cont.)
Generic RWC Emissions Control Strategy Approach
B. Reducing Mood Usage
1. Reducing home heating requirements - Weatherization
a. All households.
b. Households installing new wood stove/furnace.
2. Improving wood fuel quality
a. Select fuel with higher heating value.
b. Moisture control.
3. Direct restrictions on wood usage
a. Episode controls.
b. Emission Density Zoning.
C. Improving RWC Operating Practices
1. Initial selection of burning unit
a. Sizing.
2. Operating techniques
a. Discouraging airtight operation.
b. Charging larger pieces of wood.
3. Inspection of RWC households.
Potential Particulate Emissions Reductions (%)
B. Reducing Wood Usage
la. For 1990 3.5%; for 1995 7.0%.
Ib. For 1990 2.5%; for 1995 5.0%.
2a. No basis for emissions reduction credit,
2b. 6.2%
3a. 33% per episode day.
3b. No basis for emissions reduction credit.
C. Improving RWC Operating Practices
la. 7% by 1990; 10.5% by 2000.
2a. No basis for emissions reduction credit.
2b. 11.5%.
3. No basis for emissions reduction credit.
V-4
-------
Thus, this section describes what we believe are the primary
aeneric approaches to controlling pollution from RWC, and attempts
to quantify where possible their potential for reducing average RWC
emissions levels. These quantitative estimates or assumptions are used
in Section VI of this report as a primary basis for scoring and rankinc
alternative strategies based on the'ir relative RWC emissions reduction
p.jte r;'". i al . Fur example, these quantitative estimates vnll oe the
^fiiMcrv jas.s for scoring strategies vs >;AuT criteria -1 ana *2 in trie
Keppner-Treyoe evaluation of final strategies, in Section VI of this
report.
.. i,ir;u;Vi:,u DURING UNIT UESIG;;
1. Improved Design of New Stoves
An assessment of several stoves of advanced design suggests
that affordable stoves with participate emission rates less than
5 g/kg should be available, which is 25% of the average emission
rate (20 g/kg) assumed in this study for the current mix of existing
wood stoves (see Appendix D, Section Al for details). If an affordable
stove with emissions as low as these advanced designs can be
developed in the near future, it could provide the most effective
approach to reducing RWC emissions of all approaches examined in
this study. This assertion is verified by the higher RWC emis-
sions reduction potential estimated for the following four
strategy approaches, than for any other approaches examined in
the report (see Table 7 ).
a. Testing/Certification as Prerequisite for Sales,..
Under this strategy approach new stoves or furnaces
could not be sold if they did not comolv with established
emission limits. A standardized testina and certification
program, probably government operated, would be needed to
provide objective and consistent evaluation of burning units.
V-5
-------
uecforci, Oregon' and nissoula, Montana have advocated set-
tine, ,-;ood stove emission limits at 5 g/kg in the near future,
but neither provided for testing/certification.
Enforcement through building permit or other permit
processes is a likely proposal. However, building permits
can be easily circumvented in many communities. A new permit
process for RWC devices probably would be very unpopular,
anc possibly illegal in some states, e.g., Oregon law pro-
hibits regulation of air emissions from residential space
12
heating. If this strategy approach were applied only to air
quality problem areas within a region, cheaper, "dirtier"
stoves probably would continue to be locally available rot-
sales in competition with the cleaner units. For purposes
of this analysis, it was assumed that, under mandatory test-
ing/certification, only 60% of the new stoves purchased would
be certified - either because of circumvention of the require-
ment, or because it might be applied only to limited geo-
graphic areas with air quality standard violations.
b. Testing/Certification as Prerequisite for Sales, Plus
Tax Credit for Purchase of Certified Unit
This approach would combine the testing/certification
program described above with a financial incentive to pur-
chase the cleaner (certified) units, in the form of a tax
credit. A $400 tax credit, or 33% of the assumed $1200 price
11984), was selected for this analysis based on considera-
tions explained in Appendix D. It was assumed that this
combined strategy approach of testing/certification plus
tax credit could be 90% effective for purposes of analysis
of potential emissions reductions. That is, 90?i of the new
and replacement stoves purchased would be the cleaner (cer-
tified) units. This strategy approach was the most effective at
reducing stove/furnace emissions of any examined in this report -
achieving a 11% reduction by 1990 and 39% by 2000 (Table 7).
V-6
-------
c. Testing/Certification as Basis for Mandatory LabeTing
Uhicii Specifies Efficiency and Emissions
In this approach the thrust of testing and certifica-
tion would be to require labeling of all stoves or furnaces
offered for sale, which specifies their overall efficiency
and emissions performance, as established by the testing.
This information also coulc. be published in other ways, to
better inform consumers, in hopes that they will exercise
a preference for cleaner, more efficient units.
Shelton estimated that most stoves operate at about
40% to jO% overall efficiency in tne ..oodburner' s Encyclope-
dla, published in 1979. Some of the stoves and furnaces
now emerging in the market place have overall efficiencies
in excess of 75%, which means they can provide equivalent
heat output while using only about two-thirds as much wood
(.507.75). Since part of the manner by which these units
achieve higher efficiencies is by higher combustion effi-
ciency, a labelling program which encourages people to buy
the most efficient units will tend to encourage them to pur-
chase lower-polluting units. This is the primary mechanism
by which a labelling program could lead to lower emitting
units.
A secondary mechanism which could result in cleaner
units being purchased is the concern by some individuals
about air pollution. Some small fraction of households pur-
chasing cleaner stoves would purchase low-emitting units
in order to assist in "protecting the environment".
This approach was assumed likely to be no more than
20% effective, i.e., 20% of new stove/furnaces would be the
cleaner certified units - in part because of the likely avail'
ability of cheaper "dirtier" units, and the high influence
of purchase price on consumer choices.
V-7
-------
d. Testing/Certificaticn/Label1 ing Plus Tax Credit
This approach is the same as the one just described,
but with availability of the $400 or (33%) tax credit
described for approach 2 above.
, .ndlysis of thesi four strategies for promoting cievelopment and
installation of r.,oc₯^ c/'^anev bur^;ny stoves required a basic assump-
tion about the ^roodole availability of the cleaner units comi.iercial ly.
The following assumption v;as ir.ace for purposes of this analysis, based
on review of costs anc performance of existing advanced design stoves,
?.s aescrioed in Appen.: i < j, Section A .
ASSUi'iPTIOii: ,,ood Burning stoves will be available by January
19B4 at a cost of $1200 or less, with particulate
emission rate of 5 g/kg or less - i.e., 75% less
than the current estimated average emission rate
of 20 g/kg.
It also was necessary to postulate a level of wood fuel use which would
be altered by the implementation of any strategy approach, and how effec-
tive each strategy approach might be. Assumptions about strategy effec-
tiveness are stated above. The BASE CASE long-term trend (1970-2000)
projections of wood stove fuel use for Portland, Oregon generated in
Task 3 of this study, were used as the baseline wood fuel use rate.
Appendix D describes the assumptions used to calculate the RWC particulate
emissions reductions shown in Table 7 for these four strategy approaches.
2. Modifications of Installed Stoves/Furnaces
a. Air Inlet Modification
Barnett has reported a 50% reduction in particulate
emissions from a stove in which a simple modification
introduced inlet air between the logs near the center of the
stove. However, neither manufacturers nor homeowners seem
V-8
-------
likely to pursue this "add-on" approach to any great extent, due to
ii.eriy factors, including 1) lack of standardized inexpensive
emissions test procedures needed to keep research and develop-
ment costs down; 2) difficulty in developing inexpensive
modification kits which could be applied to existing stoves;
anc 3) difficulty and potential safety problems of "do-it-
yourself" Modification.
These authors could find no basis for assigning any
emissions reduction credit to this approach.
;;. Insertion of Fireorick in Stove box
Lining firebox walls with refractory or firebrick can
theoretically help keep combustion temperatures high enough for
good combustion efficiency - e.g., ignition of volatilized wood
gases requires 670*F. However, Harriett's research on a thin-
walled stove did not show significant emissions reduction when
a firebrick lining was added to that stove. Accordingly,
these authors assign no emissions reduction credit to this
approach.
c. Heat Transfer Improvement (Fans)
Theoretically, heat transfer efficiency could be
improved by using a fan or blower to transfer more heat into
a room that would otherwise escape through the stove stack.
If this improved thermal efficiency could be achieved without
reducing combustion efficiency, less wood would need to be
burned to provide equivalent space heating, and emissions
should drop proportionately.
Research by Shelton and Barnett suggest that
increases in efficiency through forced air heat exchange
would not exceed 5-10%. This would require 10-20% of home-
owners to install fans or blowers, in order to achieve even a
1% reduction in emissions. This is not considered likely, so
this approach is assigned a negligible (0-1%) emission credit.
V-g
-------
d. Add-on Participate Control Devices
Only this study (Task 5) and one other by the Oregon
Department of Environmental Quality J have reported emissions
test results for add-on devices to control particulate emissions
from wood stoves. The two devices tested -- a steel wool mesh
filter and a catalytic afterburner -- were inserted in the stack,
immediately above the firebox. In very limited testing 1) the
catalytic afterburner afforded 10% less emissions, which is within
experimental error, and; 2) the steel wool mesh filter reduced par-
ticulate emissions by 60% in one pair of tests when tested at a
high burn rate. In a second set of tests (2 runs) conducted in
a different test facility by a different researcher, use of the
device resulted in essentially no emission reduction.
Shelton also tested both these units for their
potential to reduce creosote deposition in the exhaust
stack. Creosote deposition is less than a perfect
indicator of participate emissions because stack temperature
differences can yield greater or lesser creosote deposition
in the stack without yielding a corresponding change in par-
ticulate emissions. In that testing, creosote deposition was
reduced by 23% by the mesh filter device and by 45% by the
catalytic afterburner. Shelton did note some clogging
problems with the mesh filter device.
The cost of these devices ($100-350), questions about
long term effectiveness, and the inevitable strong public
opposition to any regulatory requirement for their use, makes
it highly unlikely that this strategy approach could contri-
bute significantly to RWC emissions reductions in the next 10
years, (except perhaps as a design feature in new stoves).
Accordingly, their emissions reduction potential as a
retrofit approach is judged to be negligible (0-1%), based
on the limited available data.
V-10
-------
j. Improved Design or Add-on Jevices for Fireplaces
I3ecause fireplace combustion is open combustion, it is more
difficult to optimize air/fuel ratios, and residence time for
combustibles in a sufficiently hot combustion zone.
£. Underfire Air
j-ased on a single, limited set of tests by PEDCo,
IDC. a 2u/o emissions reduction appears possible by intro-
ducing air under the combustion zone of the fireplace during
burning. At a cost of $100 or less for such a fireplace
modification, this approach warrants more research -
especially at more "normal" burn rates than were used by
PEDCo. However, overall RWC emissions (stoves/fireplaces)
would be reduced only an estimated 1% by 1990 and 2% by
2000 with this approach.
b. Electrostatic Precipitator
The limited PEDCo tests also included a single test
of a commercially available electrostatic precipitator
("Smog-Hog"). A substantial emissions reduction (46%) was
achieved. However, the cost of this unit today ($1400)
effectively eliminates serious consideration of it for house-
holds. Accordingly, it was not assigned emissions reduction
credits.
c. Glass Doors
Glass doors shut during the burndown/smoldering
phase of a fire can reduce household heat loss. During
active burning, a closed glass door inhibits space heat
transfer, lowering overall efficiency. However, there is no
evidence that glass doors either increase or" decrease combus-
tion efficiency, which affects emissions. Accordingly, no
emissions reduction credits are assigned.
V-ll
-------
Three types of strategy approaches were considered in this
section for reducing wood usage: (a) reducing home heating require-
ments, e.g., through weatherization; (b) improving fuel quality, e.g.,
through moisture control (seasoning), or selection of wood fuel with
higher heat content, and ; (c) direct restrictions on wood usage, e.'-,.,
through regulatory actions such as limited bans on RWC during air
pollution episodes (episode controls), or more general restrictions
on Fu-C in air quality prooler.i areas, such as emission density zoning.
1. Reducing Home heating Requirements - leatherization
In this study, weatherization was assumed to reduce home
heating requirements by 30-50%, or an average of 40% . Since
most RWC households also rely to some extent upon some conventional
heating fuel (oil, gas, electricity), they could respond by reducing
reliance upon these conventional fuels, or wood, or both. The.
estimated range of emissions reduction derived here (7 to 16%) for
weatherization of all RWC households, depends on the assumptions used,
Two different scenarios (using different assumptions) were evaluated
to determine a range of particulate emissions reductions that could
occur. The actual emissions reductions will vary from area to area
and will depend on the percentage of homes actually weatherizing and
the changes in stove operation that occur after weatherization.
Case #1
Scenario Assumptions:
Household heating requirements = 50 million Btu/yr, with 20
million Btu from conventional fuel and 30 million from wood.
Weatherization results in reduced reliance on both fuels by
10 million Btu/yr (33% reduction for wood, 40% overall); and
15% less burn days/year (on marginally cool days).
33% of wood stove owning and weatherized households could be
"educated" to reduce their reliance on wood by reducing charge
V-12
-------
size (this would allow them to maintain their accustomed
charge interval, but a smaller fire). The remaining 67% will
use the same size of charge as before weatherization, but will
reduce the burn rate by re-charging less frequently.
Woodstove owners living in weatherized houses will replace
their oversized stoves with other oversized stoves.
60% of Oregon's RWC households need weatherization; 80% of
these could be induced to weatherize.
Results:
48% of RWC households will weatherize (60% x 80%).
There will be a 7.2% reduction in emissions from all woodstove
owning households based on no burning during 15% of days (15% x
.48 = 7.2%).
For those 67% weatherized woodstove owning households that
choose not to reduce wood charge size, total emissions on
burn days will be the same as before weatherization. The
reduced wood usage is exactly offset by the higher emission
rate (g particulate/kg wood burned) caused by the reduced
burn rate . That is, the emission rate rises proportionally
as the burn rate falls.
For those 33% weatherized woodstove owning households that d£
reduce the wood charge size on burn days, the percent reduction
in daily emissions equals the percent reduction in heating
requi rements.
33% total wood reduction - 15% total wood reduction because of no burn days _
~ ~~ -
1 - 15% no burn days
1 Butcher's equation: emission rate (g/kg) = constant (g/kg-hr) x (w°od charge size (kg
V-13
-------
That is, the 21% heating reduction equals 21% wood use
reduction which equals the 21% of emissions reduction on
burn days, for those households owning wood stoves, weather-
izing, and reducing wood charge size. This equals a 2.9%
emissions reduction for all woodstove households (21% x
.85 x .48 x .33 = 2.9%).
The resulting emissions reduction of 10.1% (2.9% + 7.2°',)
is for woodstoves only. The overall emissions reduction
for all RWC households including fireplaces is 7.1% (10.1%
x .70).
Case #2
Scenario Assumptions:
As above, 48% of RWC households will weatherize.
Weatherization results in 40% less fuel required per day,
with equal percent reductions for wood and conventional
fuels. Fifteen percent of.days are marginally cold
where wood is no longer burned after weahterization.
100% of owners of weatherized homes will either reduce the
wood charge size proportionally to reducing the burn rate,
or will burn at the same burn rate but burn fewer hours
per day after weatherization.
Oversized units will be replaced (in the 10-15 year replace-
ment time period) with smaller units after weatherization occurs.
Results
There will be a 7.2% overall reduction in emissions from wood-
stoves based on no burning during 15% of days (15% x .48 = 7.2%).
There will be a 16.3% overall reduction in emissions from wood-
stoves based on reduced burning on burn days (85% x .48 x .40 = 16.3%)
The emission reduction for all RWC households (woodstoves and
fireplaces) is 16.4% ((7.2% + 16.3%) x .7 = 16.4%).
V-14
-------
2. Improving ..OOP Fuel Quality
a. Selection of Vlood with Higher Heating Value
The intrinsic heating value of wood (Btu/air-dried
cord) can vary by a factor of 2 among different wood species
(Appendix D). while this offers soii'.e potential for reducing
R'.iC en.issions, two factors make tin's impossible to quanti-
tatively estimate, anc probably negligible. First, there is
nc information available on particulate emissions by species.
Thus rii.jher heat value may or may not correspond to higher
eriss;or,3 .j'vracteri sties. Secona, while the more co. ,,,cri
v/'ouc V--C _i. ^vc.ioL-le in the Pacific i.orthwest - '-^.,
Douglas fir, Ponderosa pine - have low to medium heating
values, supplies of wood with higher heating values are
limited. Thus, people would be unable to switch in mass to
wood of higher heating value. Accordingly, this strategy
approach was assumed to have negligible emissions reduction
potential.
b. Moisture Content Control (Seasoning)
The next two sections describe estimates for
potential reductions in RWC particulate emissions from fire-
places and stoves which could be achieved by reductions in
firewood moisture content.
(1) Potential Fireplace Emissions Reductions
For fireplaces, decreases in wood moisture content
levels result in lower particulate emission factors.
This is because more complete combustion occurs with
lower moisture content woods. Although-particulate
emission tests for fireplaces are not available for a
variety of wood moisture contents, measurements of combus-
tion efficiency for fireplaces with different wood
Ik
moisture content levels are available from Shelton
V-15
-------
(Figure 3). In this analysis the quantity J.U - combus-
tion efficiency) is usec to rnchcate relative particulate
emissions at different moisture contents in Figure 3.
Focusing on the portion of the curve between 18%
n.c. and 25% n:.c., it appears that each 1" decrease in
,;ocd ;.:cisture content yields a l.j jjcrr;.sc- . r, eirns-
jiven tr.e "~ 1 ott^M n.;. ji.i" ,,f the curve
near 2j/. i,,.c. and the ract thaL .xst ,;OOL burned in the
1 9
Pacific ilorthwest , is thought to have- ; >,.uisture
content level in excess of 2o/.. , ches-j jutrors estimate
.'"Cii 1'; decrease in ,;ooc rnoistur- c .'., :-r:t results ; r. a
Decrease -, n particulate o.iiss'iofiS ^_r : ; replaces .
Tnese assumptions are discussed in i.iore oetail in
Appendix D, Section B2b(1).
In order to derive an estimate of how nuch fire-
place emissions could be decreased by educational
programs which advocate the use of drier wood, some
estimate must be derived for how much moisture content
could be reduced. Based on several estimation techniques
discussed in Appendix D, these authors estimate that the
average moisture content of wood burned in fireplaces
could be decreased by about 2% which would yield a 1.6%
reduction in particulate emissions from fireplace burning
(2% x 0.8 = 1.6%). For an area where fireplaces account
for 30% of the total RWC emissions, a reduction of 0.5%
in total RWC emissions is derived (1.6% x .30 = .48%).
(2) Potential Stove Emission Reductions
For stoves, even though some particulate measure-
ments vs moisture content have been reported by several
researchers (Rudling et.al. , Del Green Associates,
Inc. , and Barnett ) , the most useful data is available
again from Shelton in the form of combustion efficiency
V-16
-------
FIGURE 3
Effect of Wood Moisture
on
Fireplace Combustion Efficiency
100
80
o
v.
>
UJ
a:
UJ
COMBUSTION EFFICIENCY
HEAT TRANSFER EFFICIENCY
OVERALL
_ EFFICIENCY
l l I I l l l I
0246 8 10 12 W Ife 18 20 22 2H 26
MOISTURE CONTENT C0/.^
The dependence of efficiencies on moisture content in an open
fireplace. Here power output could not be held constant but increased
with decreasing moisture content. Fuel loads were of uniform size and
were added when the previous load had been reduced to eharcoal.
Source: She!ton
Ik
V-17
-------
1 k
vs v;ood moisture content (Figure 4). l,e assume again
V ct ^articulate emissions are proportional to the
quantity (1.0 - combustion efficiency).
Based on Shelton's testing on one stove, it appears
that optimum wood moisture content lies between about 20
tc Z5'u (wet basis) with v.'orse combustion efficiency and
hence assumed higher particulate emissions at moisture
contents above and below this range. The results of six
emission tests on one stove conducted under Task 5 of
this study indicate stove emissions increase when wood
moisture content is outside the range of 20-30%, wet basis.
Despite the availability of this data, there are still
significant uncertainties - first, whether other stoves
would have the same optimum range, and second what sort
of a wood moisture content distribution is characteristic
for the Pacific Northwest. Lacking firm data on either
of these subjects, a sensitivity analysis was conducted
to estimate what emission reductions would occur 1) for
Shelton's original curve vs results if it were shifted
either 5% points to the left or right, and 2) for two dif-
ferent assumed moisture content distributions. The two
different moisture content distributions evaluated were:
1) one-third of all firewood burned has a moisture content
of 25%, one-third has 30%, and one-third has 35%, and;
2) three-eighths has a moisture content level of 25%, one-
half has 30%, and one-eighth has 35%. Differences in
emissions when these moisture contents are reduced were
calculated based on the quantity (1.0 - combustion effici-
ency), and the three different curves shown in Figure 5
as explained in Appendix D, Section B2b(2).
Table 8 shows the results for these six different
cases, which are explained in Appendix D in detail. The
V-18
-------
FIGURE 4
Effect of Wood Moisture Content
on
Stove/Furnace Combustion Efficiency
MOISTURE CONTENT (% -DRY WOOD EAS1S)
10 20 3O MO 50
MEAT TRANSFER
EFFICIENCY
10 2O
AAOISTURE CONTENT (V. -MOIST WOOD
The dependence of efficiencies on fuel moisture content in
an airtight stove. The air inlet setting was varied to maintain
an average power output of about 17,000 Btu per hour for all
moisture contents. The fuel load volume was approximately constant.
Ik
Source: She!ton
V-19
-------
FIGURE 5
Three Assumed Moisture Contents
vs
Combustion Efficiency Curves for Stoves/Furnaces
MOISTURE CONTEMT (% - DRY WOOD BASIS)
10 20 30 MO 50
MEAT TF \NSFER
EFFICIENCY
0 10 20
MOISTURE CONTENT (%-MOIST WOOD
The dependence of efficiencies on fuel moisture content in an
airtight stove. The air inlet setting was varied to maintain an
average Dower output of about 17,000 Btu per hour for all moisture
contents. The fuel load volume was approximately constant.
Source: Adapted from She!ton
Ik
V-20
-------
TABLE 8
RWC Emissions Resulting from Six Hypothetical Cases
of Wood Moisture Content Control
Curve Evaluated Assumed Percentage of Resultant Emission
in Figure 5 Wood With Moisture Reduction for Wood
Content of 25/30/35% Burned in Stoves*
C (Rightmost) 33.3/33.3/33.3 5.5%
C 37.5/50.0/12.5 3.5%
B (Center) 33.3/33.3/33.3 10.5%
B 37.5/50.0/12.5 8.1%
A (Leftmost) 33.3/33.3/33.3 11.7%
A 37.5/50.0/12.5 9.9%
* Assuming a wood moisture content reduction of 2%.
Average 8.2%
V-21
-------
results range from about a 3% to a 12% emission reduc-
tion. As a best estimate, we assume that the arithmetic
average would apply. That is, that a vigorous educa-
tional program which reduces average wood moisture by 2%
could yield about a 8.2% reduction in particulate emissions
frciiii residential wocc burning in stoves. Assjifiinc stoves
/ill account for aoout 70',, of all RUC emissions by 1933
based on Task 3 projections, total RWC emissions froni
stoves are estimated to be reducible by 5.7% (8.2% x
.70 = 5.7%) by focusing on stoves alone.
Conibirnncj the emissions reductions estimated for
fireplaces \u.5 , cinci stoves (5.7%) yields 6.2% as the .
estimated reduction in total RWC particulate emissions
achievable through programs which produce the assumed 2%
overall average reductions in firewood moisture content.
Depending upon the amount of green wood (% moisture greater
than 40%) currently being burned, significantly higher
emissions reductions could be achieved through programs
which educate owners regarding proper wood seasoning.
3. Direct Restrictions on Wood Usage
Two strategy approaches were evaluated which were based on
reducing the amount of wood fuel used in order to reduce RWC
particulate emissions. Episode controls focus on reducing wood
usage on the most severe pollution days only. Emissions density
zoning would attempt to restrict the average level of wood
burning in designated air quality problem areas.
a. Episode Controls
Ihe strategy of mandating or requesting a reduction
in wood Durnlng on poorest air quality days is referred to as
episode control. Its major advantage is that it focuses on
the time periods when emission reductions are needed the most.
V-22
-------
Albuquerque, uew Mexico has a voUirii-v\.
whereDy residents are notified of high concentrations jy a
21
pollution signal light on top of a building. In Missoula,
Montana a mandatory program has been established under which
visible snoke from solid fuel chimneys is prohibited when
^
winter participate concentrations exceed 300 ycj/.v , unless
.the solid fuel burner is the sole source of :^^t.~" ,.;ie;,
3
winter concentrations of particulate exceed 150 yg/m
residents are requested to voluntarily reduce or eliminate
ineir solid fuel burning.
...urinj winter 1981-82, particulate cc; :e; Lrv.t -. jr:3 i.
o
. . ov~uia exceeded 150yg/niJ on several occasions, out ,ic-ver
3
exceeded 300 ug/m . Based on a statistical sampling of 194
households on 6 days/month, the Missoula Air Pollution Agency
estimates that their requests for "voluntary cutbacks" were
22
heedeo in 36% of the households. Missoula officials believe
this estimate, based on sampling only afternoon burning is probably
low since most burning occurs in the evening and another survey
showed 70% of respondents stated they do not burn during alerts.
Based on this experience, these authors estimate that a voluntary
program, if well publicized, could reduce wood burning impacts by 33%
or more on poor air quality days.
Based on ratio of peak days concentration to average
winter day concentrations of 2.5*, the reduction in average
winter particulate concentrations can be calculated,
depending on the number of episode da vs.
V-23
-------
# Episode Days In
A Geographical Area
Calculation Basis
Estimated Reduction
Average Winter Par-
ticulate Concentra-
tion From Wood
Burning
4
9
12
15
18
20
25
(33%
(33%
(33%
(33X
(33%
(33%
(33%
reduction)
reduction)
reduction)
reduction)
reduction)
reduction)
reduction)
X 4
X 9
X 12
X 15
X 18
X 20
X 25
days /1 50
days/150
days/150
days/150
days/150
days/150
days/150
days
days
days
days
days
days
days
* 2
* 2
* 2
* 2
* 2
* 2
* 2
.5
.5
.5
.5
.5
.5
.5
Aver.
Aver.
Aver.
Aver.
Aver.
Aver.
Aver.
Cone . =
Cone . -
Cone. =
Cone . =
Cone. =
Cone . -
Cone. =
2
6
8
11
13
.2%
5%
.7%
.3%
10%
.1%
.'9%
Thus for an area with typically 9 winter days with
particulate concentrations exceeding 150 yg/m , a 33%
reduction in wood burning (resulting from voluntary
cessation of burning) could reduce the impacts from
wood burning on those episode days by 33% and average
winter wood burning impacts by 5%.
^Larson first identified this relationship which resulted in setting 24-hour
particulate standards at 2.5 times the level of annual particulate concentra-
tions (150 vs 60 yg/nr TSP).
V-24
-------
- Emission Density zoning
Emission density zoning could reduce particulate
concentrations if it were applied to limit the number of
installations of wood burning devices in future years in
problem areas. However, for most political jurisdictions, we
jelieve such' a strategy would face r.iajor obstacles to its
adoption and implementation. There appears to be .videspread
opposition to regulations which prohibit households from
burning wood. Such sentiments would likely result in signifi-
cant circumvention (i.e., individuals ;;urchas i n-3 a stove and
-installing it v.itiiout a "per,.-.it" ,'. era-lean enforcement
problei.i. Lastly, some State statui.es ^uc i as those governing
the Oregon Department of Environmental Quality, prohibit the
regulation of household space heating devices. Accordingly,
no practical emission reduction benefit was assumed for this
strategy.
For those interested further in this approach,
Appendix D projects how much emissions might be reduced for
three cities in the Pacific Northwest in future years, if
such a program were adopted and the compliance level were 50%.
C. IMPROVING RWC OPERATING PRACTICES
Operating procedures can have a dramatic influence on particulate
emission rates. This section assesses the emission reduction potential
from a) stove sizing, b) operating technique modifications which
include discouraging airtight operation and charging larger pieces of
wood, and c) household inspection programs for RWC households.
1. Initial Selection of Burning Unit - Sizing
Stove "down sizing" is sometimes advocated on the basis
that a smaller stove can be burned "hotter" - air supply will not
V-25
-------
have to oe restricted as ir.uch as in a larger stove to avoid over-
iieaLiii., c. roc, n or , iuoi>6. I he available literature on iiuv< ei.'.s-
sions change with operator procedures has been reviewed in order
to evaluate what emission benefits could be achieved by stove
downsizing.
In suiiii.iary, the chief benefit of dov/nsizing derives from
the fact that a si.'iiller stove will have a smaller fireuox. This
iaeans that average charge size is reduced. According to
1 °
butcher °, emission rate is dependent en both charge size and
burn rates as siio'.n ', r, the equation belov/:
where i,i = v;ooc charge size in kg
q = burn rate, in 10,000 Btu/hour
»
For a household which desires a certain rate of heat
output, downsizing a stove does not materially effect that house-
holds desired level' of heat output from the stove. Thus the "q"
term in the equation should not change when a stove is downsized.
However, since the emission rate is proportional to "m", or
charge size, a smaller firebox stove can be assumed to have an
emission rate that is proportionally lower to" the reduction in
firebox size. These issues are discussed in greater detail in
Appendix D.
24
Day has noted both that stove purchasers are tending to
purchase smaller stoves and that manufacturers also are down-
sizing their model units. He projects that average stove firebox
size will be reduced by 40% by 1990. Although the degree of
downsizing that will occur cannot be known for certain, these
authors arbitrarily assume that an educational program could
result in additional downsizing of 10% by 1990 and an additional
5% by 2000 as compared to a base case without such an educational
program. For the stove population, these assumptions yield an
emission reduction of 10% by 1990 and an additional 5% by 2000.
V-26
-------
her an area with 70% of FVn'C emissions fron, stoves, total !I',.'C
emissions would be reduced by 7% by 1SSG anc an additional 2.D>,
by 20CO.
2. Operating Technique Modifications
u. ^i scouragi ng Airtight Operation of lto>/es
Operators restrict airflow :>\, ^n/--s ": > J'.^r tc si:.'..
cowr, the stove's rate of heat production tc niaintain comfort-
able room temperatures or to extend the length of time
between stove refuel ings. Combustion efficiency can decrease
as a result of such action because the laclc of sufficient
oxygen in the combustion zone can result in less complete
combustion and a higher emission rate.
However, when an operator changes to burn hotter
(i.e., less air restriction) no benefit in reduced emis-
sions per day is realized unless the operator reduces the
number of hours per day that the stove is operated. This
issue is discussed in detail in Appendix D Section C2a.
For example, if the number of hours of operation remain the
same, and an operator increases the burn rate by 50%, the
emission rate will be decreased by 33% C(150/100)/150: on the
gram/kg basis. However, the net emissions per day on a
gram/day basis will stay constant, since 50% more wood
will be burned, unless the operator reduces the number
of hours of operation. One would expect that the hours of
operation would need to be reduced in order to maintain
a comfortable room temperature. However, comfort factors make
it unlikely that a large portion of stove operators will be willing
to shift normal operating patterns, for example, such that they
would burn at a 50% higher burn rate for two-third's of the time
and then not operate the stove for the normal last one-third of
a burn cycle. The burn rates chosen by most operators are those
which produce the desired level of constant heat output for the
room in which the stove is located.
V-27
-------
Since widespread increases in the ourn rates used by
operators appear unlikely, we ai,sic,11 no emission reduction
credit to this strategy.
b. Charging Larger Pieces of w'ooc
Charging larger pieces of wood in a stove has resulted in
a lower emission rate than burning smaller sized pieces of wood,
in limited testing. Thinner pieces of wood have a large surface
area to wood ratio which allows them to heat up relatively fast
and release their volatiles at a fast rate. The high rate of
volatile production can result in an oxygen deficiency in the
combustion zone which results in less than complete combustion
and higher particulate emission rates.
This phenomenon has been noted by both Cooke and Allen of
Battelle and by Barnett \ Barnett developed a best fit equation
based on tests with a thin walled stove which relates particulate
emission rates to log diameter. This is discussed in more detail
in Appendix D. For wood in the size range between 2" and 6",
increasing log diameter by about 2" results in 33% decrease in emission
rates (i.e., 4-6" range is optimum).
An education program to convince operators to burn larger
size pieces of wood appears to have strong potential as an education
strategy, assuming additional testing confirms these preliminary
findings. Unlike some other strategies to change operator behavior,
there is no inconvenience disincentive for this change in operating
practice. In fact, less splitting of wood requires less work. These
authors estimate that an education program could result in 50% of
operators increasing their average piece size by 2". For stoves, this
means this strategy has an emission reduction potential of 16.5%.
Barnett's equation for predicting emission rates
based on log diameter was developed based on stove burning
rather than fireplace burning and thus this strategy only can
be assumed to apply to stoves given current evidence. For an
area where stoves account for 70% of RWC emissions, total RUC
V-28
-------
emissions are thus assumed to be reducible by 11.5% (33% X
.0 x .7 = 11.55%;. If later research were to show a similar
relationship applies for fireplaces, then total RWC emissions
would be assumed to be reducible by 16.5% by this strategy.
j, Periodic Inspection of Rl.C Equipment
^...ij^sficri e:..ju;,,!. ont inspections can nJcr.tify when
oqu'ipir.ent performance is aeter iorating and promote more rapid
restoration of the equipment to original performance levels.
nigher combustion efficiency results in less air pollutant
j, i ssions.
Ueyarding whether inspection programs are a feasible ii.eans
for reducing emissions from residential wood burning, we judge
that political and legal obstacles make this strategy unlikely to
be implemented in most communities. Oregon statutes prohibit the
Department of Environmental Quality from regulating home space
1 o
heating devices. Aside from legal obstacles, many citizens are
opposed to the concept of an inspector entering-their dwelling
and requiring equipment changes.
Potential benefits of an inspection program include the
following:
* Safety
33% of fires in Oregon in single family dwellings are
25
associated with solid fuel heating equipment. If an
inspection program were to focus on safety aspects also,
significant savings in personal property and lives could
result.
Maintaining Catalyst Performance
Catalyst stoves can deteriorate with time in terms of
the catalyst losing its efficiency because of deterioration
of the catalyst coating. For example Corning Glass Works,
V-29
-------
catalyst has a GOC'J hour nfet'iuie.""1" Fur u stove operatec
20 hours/day for 5 months/year, this equates to a 2 year
lifetime. In the event catalyst stoves ever account for a
significant share of the stove population, an inspection
program could help to ensure conciivj-jc ._.oou combustion
efficiency (i.e., recuced ei.^ssioi^; fo^ this type of
stove.
i'.u'intaiiTing rn<,h Coubiistion Efficiency
Trr, s benefit is specul ati v_-. r~jr uniis ,,it!i nigh (i.e.,
^-', combustion cffic'ieticy ./iLh ,.<'.-,^ic u;r supply
arrangements, maintenance may becouie ,:;ore iniportant to
iiiaintain this high combustion efficiency, than it is for
less complex units with 80% combustion efficiency. As one
example, units which channel some gases with combustion
products through small air holes may experience "hole
plugging" with time. An inspection program could identify
and correct such problems.
" Adv-ising Operators with "Smokiest Chimneys"
Such a strategy is a combination of an inspection program
with an educational program. Most of the benefits achiev-
able by such a program would be associated with changes
in operating procedures rather than equipment repair. It
is probable that the 10X of operators who burn in a manner
producing greatest emissions account for more than 20% of
total emissions.
Despite these potential benefits, we assume political and
legal obstacles will make this strategy uniuiplementable in most
communities and thus assign no emission reduction credit to this
strategy.
V-30
-------
VI. LLLECTIOii AMD EVALUATION OF FINAL RWC CONTROL STRATEGIES
Section A describes the final list of RWC control strategies
selected for evaluation and ranking. Section B describes the evaluation
and ranking, which employs the full (three-step) Keppner-Tregoe
jvdlijction process.
n. SELECT I On OF FliiAL R'wC CONTROL STRATEGIES
, :any combinations and variations of the R'.iC control strategy
:u-. ,;i'.^ described and evaluated in Section IV conic je used to control
,>,.C ii,^uc:s under a variety of local conditions. The list of i"!»;C
control strategies described in this section is considered to be a
cross section of practical, effective strategies. They were selected
to represent one or more of the following:
. Leading examples of RWC control strategies implemented else-
where and which seem viable for implementation in other
locations;
Combinations of strategy elements recommended for evaluation
by air pollution control agency staff, or study team members;
Other combinations which seemed promising, based on the evalua-
tion of individual control strategy elements (Section IV),
Rl-jC emissions reduction potential (Section V), and other con-
siderations
Trie "availability" of some of the key elements of these strategies
depends upon the adoption of local ordinances, or the establishment
of financing programs - e.g., loans for weatherization. However, most
of these proposed strategy elements have a precedent - e.g., an actual
VI-1
-------
situation in ,,mci! comparable ordnances cr financing has jeen estab-
lished. Accordingly, for purposes of this evaluation, these elements
vvere assui.ieo to be feasible.
Table 9 summarizes tne fifteen RUC particulate control strategies
selected for final evaluation using the full (three-step) Keppner-Treyoe
process. The following subsections describe fifteen hypothetical iV.,C
control strategies selectee for final evaluatiori anc rankiny. The
liiajor elegants of each strategy arc- Driefly described, followed by
additional comments.
1. Testing ana Certification as Prerequisite to Sale or
Installation of »'oou Stove/Furnace
.iianoatory emissions testing and certification that emis-
sions do not exceed'standards (£5 g/kg) established
oy government, is required to allow sale or installation
of wood stoves/furnaces.
Government provides and operates facilities for testing,
and adopts standard test procedure.
Equipment certified for sale must be labeled as to its
tested emission rate (g/kg of wood burned).
Government publishes results of all tests and requires
retailer to provide this information to prospective
buyers.
Government recoups some costs by charyin<_ fees for testing
and certification to manufacturers.
Applies to new and replacement or retrofit units anywhere
within jurisdiction of adopting agency.
Building permit required to install new or replacement
stove/furnace. Only certified units can obtain permit.
This strategy is the first of five based on testing emissions
from stoves/furnaces using standardized test procedures developed
by government. In the first four of these, government also
provides test facilities and conducts the testing, recouping
VI-2
-------
Ll./
Strategy ir7
Strategy ffC
Strategy #9
Strategy #10
Strategy #11
Strategy £12
Strategy #13
Strategy #14
Strategy £15
i estiny'Certif ;cation as Prerequisite to Sales or
Installation of ,;ew Stoves/Furnaces
as _'.<;S", ^ ."or . ioriL.dtor
o
, o ,\e,- Stov
Furnaces Prior to Sales; Label Specifies Emissions
Performance and Efficiency
r u r- -, + ,. , - o t I.* n ' ' T -, < ,~ * ,-w-i - t- c ', - - r. r, '
^» L . G i^ t. ^ j ' O ^ ., i L11 ^ j i u A U f trO i L, x ^'i ou . \.JO /
fv "^ i ';-!.; b ,,i"j i )'(.:(.£ .-.SSOC 1 at 1 Oii
.- 3 '. i ' , / , , o u
i.uiiuetory
-------
as ;..'uch costs as possible by charging Manufacturers to test their'
jriits. In the fifth strategy described below, emissions testing
and labeling is carried out by an RUC Industry Trade Associa-
tion.
The government established ceiling on emissions allowed is
5 g/kg of wood burned. Any stove/furnace must emit £5 g/kg to be
certified, and only certified units may be sold or installed. The
building permit required to install new, replacement, or retrofit
units is intended to help enforce the strategy. The larger the
geographic area in which this strategy was applied, the more effective
it would be, with fewer opportunities for nonregulated markets to
legally offer non-certified units.
Besides emissions, units could also be tested for combustion
and .thermal efficiencies, if desired.
2. Testing and Certification as Prerequisite to Sale or
Installation Plus Tax Credit
Same as Strategy #1, plus financial incentive in form
of a tax credit.
A $400.00 tax credit would be available to purchasers
of new certified stoves/furnaces. This is 33% of the
assumed average cost of $1200.00 for certified commer-
cialized stoves/furnaces (see Appendix A, Section A).
Other types of financial incentives could be used - e.g.,
direct rebates of a portion of the purchase pric"e. This tax
credit was used itt Section VAT of this report, in estimating
potential particulate emissions reductions achievable by various
strategy approaches.
VI-4
-------
5. .Tesfin.j as ^asis for .Mandatory Lapel inc; Prior to Sales
ilaudatory testing to determine emissions of all stoves/
furnaces offered for sale.
Government provides and operates facilities for testing,
ar,c adopts standara test procedure.
';! equipment sold must be labeled os Lc 'ts le^tcc
v.,iJS'ion rate (j/kcj of wood burned;.
uovernuient publishes results of all tests and requires
retailers to provide this information to prospective
vr/ers.
..c.'Vcrrih.ent recoups some costs by charging fees for testing
and labeling.
Applies to new and replacement or retrofit units any-
v/here in the jurisdiction of adopting agency.
Enforcement by inspection of retail outlets for non-
labeled units.
In this approach, all stoves/furnaces sold commercially
must be tested by government and labeled as to their emissions
rate (g/kg). This strategy relies on publicity to encourage
consumers to purchase cleaner burning stoves and furnaces - i.e.,
determining and publicizing their emissions rates - much like
publicizing automobile gasoline mileage test results.
However, whereas better gasoline mileage can save money
for purchasers of autos, better emissions performance has little
or no direct monetary payoff, except to the extent that higher
combustion efficiency (less unburned exhaust products) increases
overall- efficiency and decreases the chance of house fire from excessive
creosote build-up. Cleaner burning stoves may well be more expensive too,
due to extra engineering or materials costs. Without the regulatory pro-
hibition against selling units with high emissions, which strategies #1
have, consumers are free to purchase "dirtier" units, and probably would
VI-5
-------
if they are cheaper. For those reasons, this testing/labeling strategy
approach was assumed to be only 20% effective in reducing particulate
emissions (see Section II Bla(3)). This is, only 1 in 5 new stoves/
furnaces purchased under this strategy approach would be the cleaner
units (i.e., emit <5 g/kg).
4. Testing/Mandatory Labeling Plus Tax Credit
Same as Strategy 13, plus tax credit.
A $400.00 (33%) tax credit would be available to purchasers
of new stoves/furnaces which emit <5 g/kg of particulate.
The tax credit assumed to double the effectiveness of Strategy #3
(to 40%) but not equal the effectiveness of either strategy #1 or #2,
which allow only certified stoves to be sold. Table 7 in Section V
summarizes the estimated emissions reductions achievable for each of
these first four strategies.
3. Testing/Rating By RVJC In'dustry Trade Association
RWC Industry Trade Association establishes facility to
test burning units for emissions (and efficiency).
All association members must participate and all of their
commercially available units must be tested in order
to be rated.
Emissions rates (g/kg) must be labeled on burning units
offered for sale.
Trade Association must aggressively publicize its rating
system and urge consumers to buy only rated units, and
to minimize emissions, consistent with other desirable
features - e.g., energy efficiency, heating needs,
appearance, etc..
Mandatory labeling also must include information on sizing
burning units to match heating needs - i.e., how much
space can be heated with unit, at various insulation
levels.
VI-6
-------
association must publish information explaining importance
of not oversizi'ng heating units, and how to select proper
size, using industry ratings.
This approach is like Strategy #3 above, but with industry
instead of government implementing it. It has precedent in other
traoe association testing programs like the testing anc rating
of refrigeration equipment by the Air Conditioning ana Refrigera-
tion Institute and electrical equipment testing by the Under-
v/riters Laboratory. This strategy approach calls for a vigorous
industry effort to publicize test results, and even to encourage
use of cleaner, properly used units. The traditionally neutral
role of trade associations regarding purchase of particular
classes of products might make this strategy hard to implement.
There also is no stove/furnace emission standard which
is uniformly accepted, or government approved test procedures.
This strategy relies upon the industry to monitor itself, and
to develop internal means of encouraging cleaner burning stoves/
furnaces. There is no effective way of forcing diligent effort
by industry, except perhaps a commitment by government to do so
if industry is not conscientious. This strategy would only be
feasible on a national level, not local.
u. .;eatherization of All Households
Establish Energy Conservation/Air Quality office in
government to coordinate and aggressively promote
weatherization benefits, and help citizens get it done.
Mandatory weatherization of all households to minimum
cost-effective standards or better, beginning four years
from effective date of enabling local ordinance. Prior
to this, weatherization is voluntary, giving owners time
to plan for compliance, and eager households the
opportunity to obtain earlier benefits.
VI-7
-------
/vpltCuulc to : 11 residences up to 4-plex in size, ana
ouilt. prior to ... (oate adequate insulation stariJarcs
for new homes adopted in a given community).
Ueatherization requirement applies within 9 months of
requested change in utility service and is the respon-
sibility of the nev,' owner, or landlord for a rental
occupancy change; or at time of installation of a wood
burning appliance in a residence.
Applies to homes heated with electricity, oil, or natural
yas.
Utility inspects premises, assists owner in obtaining
reputable contractor or in doing work himself. Utility
inspects anc approves final work and pays for it. Where
weatherization is required due to new RwC appliance,
utility helps determine proper sizing vs. insulation
levels.
Owner repays utility at a monthly rate such that his
cost for weatherization plus heating fuel is not greater
than his cost of fuel without weatherization.
In Section V weatherization is estimated to be one of
the more effective strategy approaches to reducing RWC particulate
emissions. This is the first of two weatherization strategies
evaluated, both intended to reduce RWC emissions by reducing
the space heating requirements of RWC-households. This particu-
lar approach would require eventual weatherization of all under
insulated households, beginning four years after its adoption,
allowing a voluntary phase in period. It is modeled after pro-
grams in Eugene and Portland, Oregon (see Section II F), and
includes a leading role for both government and private utilities
(oil, gas, and electric).
Its most controversial element could be its financing
requirement that payments on no- or low-interest weatherization
VI-8
-------
loans not exceed the previous cost of fuel v/ithout weatherization.
Lenders might balk at such a flexible arrangement. Not much
data is available yet from existing weatherization programs to
reveal how much pre-weatherization fuel costs are actually lowered
by insulation. However, an attractive financial incentive is
needed to r.iEke the :i;>jh initial cost of weatherization politically
tjolataole as well as affordable to a large segment of the
population. Weatherization has obvious energy conservation
benefits, and has been promoted primarily for this purpose.
7. Mandatory Weatherization Only for Households Installing New
Wood Stove/Furnace
Weatherization to minimum cost-effective standards or
cost effective level is required to install a new
(including replacement) stove/furnace in a residence,
hotel, or restaurant.
Effective in four years from date of enabling ordinance
enactment.
Financing from low- or no-interest loans from government
or utilities, who also provide technical assistance and
referral to contractors or lenders.
Require permit for stove/furnace installation, and
evaluation of proper size for RWC equipment, based on
insulation requirements, during permit review.
*
This approach would require weatherization only for house-
holds and commercial buildings installing new (including replace-
ment) wood stoves/furnaces. Other RWC-households would be
encouraged to voluntarily weatherize by allowing them to obtain
VI-9
-------
the same financial aid. Tins approach is patterned after similar
iv.iC controls adoptee in Jackson County vMedford} Oregon (Section
II E).
Since presumably fewer households would weatherize, less
loan funds would be needed. Cost-effective insulation levels
would be defined as those capable of cost payback in 5-7 years,
baseo on saved conventional fuel costs. However, this approach
unlike Strategy #6, does not try to assume that the monthly costs
of weatherization (loan) plus conventional heating fuel costs
do not exceed pre-weatherization fuel costs.
Enforcement by installation permit 'will be more or less
effective Cependinc, upon ti;s incentive for stove purchasers to
circumvent this regulatory approach. If such persons feel
unfairly singled out, and initial costs are too burdensome, cir-
cumvention may be high. This approach also may discourage
replacement of older stoves/furnaces with newer, cleaner burning
models, and/or discourage initial purchase of wood stoves/
furnaces. These two factors would have opposite effects on RWC
emissions reductions over time.
8. Firewood Moisture Content Control
Government would undertake a major public relations cam-
paign to promote proper seasoning of firewood, including
use of broadcast media, brochures, and other forms of
public information.
Commercial firewood suppliers selling more than 10 cords
per year would be required by law to state moisture
content; moisture content meters would be made available
to such parties at low or no cost.
Cooperation of agencies or private companies who supply
firewood would be sought - e.g., to encourage firewood
gathering as far as possible in advance of the heating
season.
VI-10
-------
Information and possibly technical assistance in proper
wood storage would be provided.
This strategy will reduce emissions from fireplaces as
v/ell as stoves/furnaces, although most of the emissions reductions
are estimated to occur for stoves/furnaces. Section V
estimates that the potential emission re::uct ,ur,s_ fr\,,. -lOisiure
control are among the highest of al1 strategy approaches evaluated
(see Table 7).
This strategy's effectiveness depends on tne degree to
v,'nch ^uulic infor^cit ton can persuace pcu^le 10 ^ry their v.'ocd
more effectively, thereby lowering the average moisture content
of firewood used. In Section VB2 a a 2" reduction in wood
moisture content was estimated to be reasonably achievable.
This reduction was estimated to reduce Ri-.'C particulate emissions
by 6.2% for an area like Portland, Oregon, with about 92% of
the reductions coming from stove/furnace emissions. The high
percentage of emissions reductions from stoves/furnaces occurs
for several reasons, including: a) a high percentage (70%) of
total RWC emissions is attributable to stoves/furnaces; and,
b) stove emissions factors are more sensitive to moisture content
than fireplace emissions rates (compare slopes of combustion
efficiency curves in Figures 3 and 4 -jn Section V).
9. Stove Sizing
Government would encourage proper sizing of new wood
burning units, promoting the minimum siz£ unit consistent
with desired heat output and insulation requirements.
Public information would be provided on the benefits
and method of selecting a stove/furnace of appropriate
size.
VI-11
-------
ctiilers of stoves/furnaces would be suppl iec with ana
required to i.;ake tlvis information available to purchasers
before they buy.
A permit (e.g., building permit) would be required to
install a wood stove/furnace. Part of the permit
application process would be an evaluation of the size
of the burning unit vis a vis the space it will heat.
Decreases in average house size, increasing stove/furnace
costs, and increasing weatherization are among factors that will
tend to naturally decrease the average size of wood burning units
in the future. At least one national expert believes that the
average stove firebox size will decrease by about 40% by 199C.24
In Section V, decreases in average stove size of 10% by
1990 and 15% by 2000 were estimated to afford decreases in RWC
particulate emissions of 7% and 10.5% respectively (Table 7).
This strategy potentially affords both significant emissions
reductions and savings to those consumers who would otherwise
have bought a larger, more expensive stove. Less creosote
problems also should occur, because a properly sized stove can
operate with more efficient combustion at a given burn rate.
Some inconvenience may result in that smaller average wood charge
size may require inore frequent charging.
1C. Encourage Larger Wood Piece Size
Government would conduct research to confirm that
increased average piece size reduces emissions, and to
determine optimum piece size.
* Government would encourage burning of larger average
size pieces of firewood through public information.
VI-12
-------
This strategy approach seei.is to offer the potential for
significant (11-12%; Table: 7 / reductions in i<>;C e,';,issions v.'ith
no inconvenience to operators. However, since the emissions
reductions estimate was based on a single emissions test conducted
1 ;
on an airtight stove ', further research is needed to confirm
or refute this potential uefore a major promotional effort "is
vj 11 c e r t £ k e n.
The strategy presently is assumed to reduce emissions only
for stoves/furnaces not fireplaces, pending further research.
": . require Fireplaces To Have Underfire Air Source
Government would conduct research to confirm the emis-
sions benefits of underfire air. If significant benefits
are confirmed, government would require new fireplace
installations to include underfire air devices.
Government would require through building code or
ordinance that new fireplaces include a simple device
for introducing air under the combustion zone.
This strategy's emissions reduction benefits are limited
to fireplaces, which will represent a decreasing fraction of
total RWC emissions according to Task 3 analyses. The basis for
the estimate in Section V of emissions reduction benefits
from underfire air was a single, limited series of emissions
tests. Accordingly, additional tests of th'is effect should
be done before it is promoted by government, especially for
retrofit of existing fireplaces. However, its low cost and high
potential emissions reduction, based on limited data, warrant
priority research attention. Modification of a fireplace to
have underfire air should cost less than $100.00.
VI-13
-------
12. Episode Controls
Voluntary curtailment of RUC whenever 24-hour particulate
levels (TSP) exceed established levels: TSP 150 ug/m0,
or 60 yg/m of "respirable" particulate (_<2um).
Mandatory curtailment of Rl-.C duriny such episodes If
voluntary approach does not prevent further air quality
deterioration during trie next 3 years - i.e., if peak
and average pollutant levels worsen.
Enforcement by visual opacity checks (day only) and
revocation of permit required for installation of RWC
equipment.
Public education (media; brochure) to promote positive
attitude towards program which could increase compliance.
This strategy is based on a similar program (see Section
II D) adopted in Missoula, Montana and in Vail, Colorado.
Bedford, Oregon also has adopted siniilar episode controls as
part of a multi-faceted RVJC control program (see Section II E).
The chief benefit of this strategy is emissions reductions on
worst air quality days, estimated at 33% per episode day in
Section v. The extent to which such air intermittent strategy
would reduce seasonal or annual average emissions depends upon
the number of episode days per season or per year.
13. Research and Development of Improved RWC Equipment or
Operating Procedures
Government would undertake and/or promote private or
academic research and development of improved RWC
appliances and practices and actively disseminate the
resulting information to private parties for commer-
cialization, and to the general public to encourage use
of improved RWC appliances and practices.
VI-14
-------
'oov-jrn...eni ^rov^^i .-. rr^j, rVi ly ^taffec e., .ssions ttst.
facility, cinci Develops stancardizeci test procedures.
These are made available at low cost for promising
research, along with technical advice and assistance,
to researchers with promising ideas.
uoverniuent offers attractive monetary av/aros (S5U,JGO
above costs, Lu designer or manufacturer of first WOOL
burning stove that emits <_!
-------
units. These are needed to encourage innovative designs, by
^roviuuin inexpensive information to guide design/development
of improved equipment/practices. Research incentives, such as
the prizes described above, would be supplemented by active pro-
motion and encouragement of promising research, through research
grants, seminars, publication of results, etc..
;,o attempt v/as made to estimate potential Ill.'C emissions
reductions attributable to R&U efforts because they are too
unpredictable, and because R&D funding would be especially hard
to obtain in the present sluggish or depressed economy.
':> Encouraging Alternative Fuels
To discourage RWC for space heating, the government could
undertake efforts to encourage alternative fuels use,
including the following measures:
Require utilities to offer lower rates for space heating
with oil, natural gas, or electricity, by allowing or
encouraging compensating rate increases for other uses.
Encourage lifeline electricity rates.
Promote the use of passive solar energy for space
heating, natural gas radiant heaters or fireplaces.
Restrict firewood supply by:
Limiting access to state and federal lands for fire-
wood cutting to spring and summer.
Limiting total firewood removal from state and federal
lands, based on analysis of air quality impacts of
local use.
.Encourage alternative uses of logging residues - e.g.,
subsidizing pilot programs for use in pulp and paper
making, or thermal power plants of appropriate scale.
VI-16
-------
1,;', s is the on\j strategy approac,* tnot Directly attempts
to o", scourace U'.fC over the long-ten, - i.e., dz.te:,.pts tc ois-
ccurage new kUC-households and induce existing Ui.C-households
to cease RWC or to rely more on other means of space heating.
The first three measures mentioned above provide positive alter-
natives to RWC by encouraging the use of solar energy cr conven-
tion fuels. The last three i.,easures simply restrict wood supply
cirectly, which could prove unpopular, and hence politically
difficult to implement. Encouragement of conventional fuels
- especially oil - is contrary to national policy ot increasing
energy independence, .iowever, conventional fuel use ,,iay be less
rol lut'ing, and offer more stable supply than firewood.
15. Periodic Inspection of RWC Equipment
Require annual inspection and maintenance of residential
wood-fired space heaters, by professional chimney sweeps
in designated problem areas.
Inspections would test emissions of home heating equip-
ment and evaluate safety.
Identified equipment maintenance requirements must be
corrected within 30 days to avoid civil penalty (up to
$500.00) and reporting of the deficiencies to fire
insurance companies.
Inspectors also could provide information and technical
assistance on RUC practices such as wood storage and
stove operation.
Roving inspectors could respond to visual evidence of
poor Rv-iC practices, or complaints of same.
Some European countries like West Germany (Section II C)
have long had residential inspection of large conventional fueled
residential space heating devices. Extrapolating such a program
VI-17
-------
to solid fuels (wood, coal) may prove less productive since a
solid fueled stove cannot be cleaned and tuned for iir.proveo fuel
efficiency like an oil burner can. wood burning stoves equipped
with a catalyst unit to enhance combustion could be checked for
retraining catalyst life/effectiveness to assure more timely
replacement. Also, as stoves Decode more sophisticated, the need
for periodic inspection/maintenance increases, if high coi.ibustion
efficiency is to be iiiai ritai ned.
Inspection for safety purpose - e.g., creosote build-up
in flue - could be the cornerstone of this approach, since so
?5
many nome tires can oe associated with RUC.
Inspection i;,ay be rr.ost effective where the number and lype
of RUC devices is controlled - e.g., where only tested/certified
units can be sold or installed, or for subdivisions or other
residential developments where the developer can impose restric-
tions on RWC.
The Section IV evaluations indicated that the most effective
types of RWC controls include: proper sizing of wood burning units,
home weatherization, emissions testing and certification of RUC
appliances as a condition of sale and use, incentives to use cleaner
burning appliances, and wood moisture controls. The fifteen final
strategies utilize all of these approaches and various combinations
with supplementary strategy elements.
For example, the first five final strategies are based upon
testing and certification or labeling of RWC appliances, and in several
cases, compliance with minimum emissions standards is required. Severa:
different weatherization approaches are proposed - one requiring
weatherization of all households (#6), another requiring it only to
install a new RUC appliance (#7). Proper sizing of RWC burning units
VI-18
-------
is e,,iphasi zee. in the first seven strategies. Likewise, incentives
and v.ooo iiioisture controls are emphasized in several strategies.
Disincentives to Ri.'C also could be employed - e.g., an emissions
tax to discourage-use of more polluting RWC appliances. This was not
included in the final strategies evaluated because the price elasticity
of dei;iana was too difficult to determine. Also one would expect the
jutcci-.e or benefits ~u be sii.rllar to those obtained with tax credits
iStrategies ,-rZ, ;-4;. Strategy ,,'14 contains the disincentive of
restricting firewood supply.
... KEPPNER-TilEGOE EVALUATION OF FINAL RWC CONTROL STRATEGIES
The full three-step Keppner-Tregoe evaluation process describee
in Section III was applied to the fifteen final RWC control strategies
summarized in Figure 6. All strategies satisfied all MUST criteria,
with one major caveat. Full implementation of a number of the
strategies would require the establishment of financing programs or
additional legal authority, through adoption of local ordinances or
possibly state laws. Adequate legal authority, and commitments of
resources to implement proposed RWC control programs would be necessary
to include any of them in an air pollution control program for a local
area that could be officially approved by the U.S. Environmental
Protection Agency as "meeting all legal requirements established by
the Clean Air Act" (MUST criteria #2).
1. Ranking the Final Strategies Using WANT Criteria and
Risk Factors
The evaluation of all fifteen strategies v'ersus the twelve
WANT criteria is documented in Appendix E. This appendix contains
individual scores assigned to each strategy, for each WANT
criteria (Appendix E, Table E2), and explains some of the major
reasons for the scores given. It also describes the major adverse
VI-19
-------
FIGURE 6
Summary for Fifteen Final RWC Control Strategies
of the Keppner-Tregoe Ranking
vs
WANT Criteria and Major Strategy Costs and Benefits*
RWC Control Strategy
1
Keppner-Treoge Ranking
vs WANT Criteria2
(Rank) (Points)
Estimated
Implementation
Costs3 ($)
3 4
Benefits ' of Implementation
Testing/Certi fication;
Tax Credit (Strategy #2)
1
535
-$50.000 K
-$130,000/year
-$1.8 -7.2 million
per year tax credits
7
Potential Emissions Reduction (%)
1985 1990 1995 2000
11
30
39
Testing/Certi fication
(Strategy #1)
Larger Firewood Piece Size
(Strategy #10)
Testing/Labeling; Tax Credit
(Strategy #4)
508
490
469
-$130,000/year
-$50,0005
-$45,000/year
-$50,000b
-$160,000/year
-$0.8 - 3.2 million
per year tax credits
-Potential Emissions Reduction (%)
1985 1990 1995 2000
2 8 22 30
-Potential Emissions Reduction:
11.5%
-Potential Emissions Reduction (%)
1985 1990 1995 2000
7
1
15
21
From Table 9.
From Appendix E.
From Appendix F.
One time start-up costs.
Annual administrative costs.
From Appendix D.
Based on $400 per certified unit;
5,000 to 20,000 total units sold,
and % of total units sold assumed
to be certified units.
* Refer to discussion in text regarding
assumptions used in arriving at rankings. VI-20
-------
RWC Control Strategy
1
FIGURE 6 (Cont.)
Stove Testing/Rating by
Trade Association
(Strategy #5)
Keppner-Tregoe Ranking
vs WANT Criteria2
(Rank) (Points)
Encourage Alternate Fuels
(Strategy #14)
Research and Development
(Strategy #13)
Stove Sizing
(Strategy #9)
Testing/Labeling
(Strategy #3)
Mandatory Weatherization
for All Households
(Strategy #6)
10
458
445
443
438
432
422
Estimated
Implementation
CostsJ ($)
3 4
Benefits ' of Implementation
Not quantifiable
Not quantifiable
-$45,000/year
-$50,000b
-$130,000/year
-$150,000 to
$600,OOO6
-$1,400 to
$1,500 per
household
$50,000/year5'J7
$130,000/year '
Not quantifiable
Not quantifiable; but significant
- can enable many other strategies
to have their efficiencies improved
-Potential Emission Reduction (%):
1990 2000
7%
10.5%
-Potential Emission Reduction (%)
1985 1990 1995 2000
1
11
Potential Emission Reduction (%)
1990 1995
3.5 - 16.O8 7.0 - 16.O8
-Potential Emission Reduction (%):
1985 1990 1995 2000
1
8
11
1
From Table 9.
From Appendix E.
From Appendix F.
From Appendix D.
One time start-up costs.
Annual administrative costs.
7 Costs paid by private sector.
8
Emissions reduction depends on assumptions
used regarding changes in RWC practices
after weatherization.
VI-21
-------
FIGURE 6 (Cont.)
RWC Control Strategy
1
Keppner-Tregoe Ranking
vs WANT Criteria^
(Rank) (Points)
Estimated
Implementation
Costs ($)
3 4
Benefits ' of Implementation
Mandatory Weatherization
for New/Replacement RWC
Households
(Strategy 17)
11
411
-$20,000 to ,
$80,000 per yearb
-$1,450 per house-
hold.
-Potential Emission Reduction
1990 1995
3.5 - 16.O7 7.0 - 16.O7
Moisture Controls
(Strategy #8)
12
400
-$45,000/year
6.2%
Episode Controls
(Strategy #12)
Annual Inspection
(Strategy #15)
Underfire Air Controls
for New Fireplaces
(Strategy #11)
13
14
15
381
321
-$25,000 (
-$8,000/year
-$.75 to 1.5
million/year
for an area
with 50,000 tofi
100,000 stoves.
-$.1 to .3 mill ion/
year installation
costs for an area
with 1,000-3,000 new
fireplaces per year.
33% reduction on Episode days
-No emissions reductions credited,
-18% less home fires (est.).
-Lower fire insurance costs.
-Potential Emission Reduction
1990 2000
1%
2%
From Table 9.
From Appendix E.
From Appendix F.
From Appendix D.
One time start-up costs.
Annual administrative costs.
Emissions reduction depends on assumptions
used for changes in RWC operation after
Weatherization.
VI-22
-------
cxr.s-^Jtrioes viVisx, Factors,1 identified with Ti,.plei,ientinij each
strategy \nppenoix £, Figure Elj. These were not considered
sufficiently problematic to warrant changing the ranking estab-
lisneo by the total .1ANT criteria scores assigned to each
strategy.
The final ranking of all fifteen strategies versus all
twelve ;;AiiT criteria is shown in Figure 6. This represents the
relative satisfaction of all twelve U'ANT criteria simultaneously
- not the relative RWC emissions reduction potential which was
only one of the twelve criteria.
c. ::L:^; c^sTi /;;; JL.ILFITS OF FINAL RWC COK-TI-OL STRATEGIC
As described in Section III E, as a companion analysis to the
Keppner-Tregoe evaluation of strategies, selected costs and benefits
of implementing the strategies were considered. For the fifteen final
RWC control strategies, the estimation of such costs and benefits is
described in Appendix F. The results of this analysis- are the costs
and benefits summarized in Figure 6.
Cost estimates presented include mostly administrative costs.
These are often quite speculative, although they are based on experi-
ence from existing agency programs, or expert opinion, where such
information was available. While public and private sector costs
were considered, no extensive data gathering on this was feasible for
this study, so the resulting cost estimates are preliminary and approx-
imate. Nevertheless, they serve to indicate gross differences or
similarities in the relative administrative costs of implementing
various strategies.
The benefits summarized are intended to highlight the major
achievements anticipated by implementing each strategy. The first
such achievement is a quantitative estimate, if available, of the amount
by which the strategy could reduce RWC emissions, either in the short-
er long-term. Section V (and Appendix D) is the source of these
VI-23
-------
-r -
estimates. Other benefits include achievements such as energy cu.r.s
vation, satety erii'.aricei,;eirc, avoiding "inconvenience, eic.. [juf.cM^
not quantifiable include the incremental health and visibility
benefits from the pollution avoided.
Figure 6 summarizes the costs and benefits estimated in Appendix F,
along with the overall ranking of the 15 strategies against all WANT criteria.
1 . L>est Emissions Reductions
The t',,G strategies v/hich ranked highest against all '.JAi;T
criteria (Strategies £2 and #1 ) also provide the highest percent-
age reduction in RWC particulate emissions - 39% and 30% respec-
tively, by the year 2000. Both involve mandatory testing/certif-
ication and prohibition of the sale of wood stove/furnace models
which can't comply with government emission standards (£5 g/kg
suggested standard).
This strategy approach is very effective over time in lower-
ing emissions, as these new units replace existing stoves/furnaces
which emit, on the average, four times as much particulate
pollution. This approach requires years for its maximum benefits
to accummulate.
Both strategies restrict consumer choices dramatically,
which could produce public opposition, if such limitations are
perceived to have caused the price of remaining stoves to rise unrea-
sonably. To help avoid this the top ranked strategy (#2) includes
a financial incentive (33% tax credit estimated at $400/unit in 1984)
This in turn makes this the most expensive strategy of all those
reviewed, with likely annual costs (tax revenues foregone) in
the millions of dollars for a program of statewide scope.
Such costs seem to be appropriate and manageable. Oregon has
spent hundreds of millions of dollars over the last decade in
VI-24
-------
pollution control tax credits for industrial control equipment.
The Brewing evidence that Rt.'C particulate emissions approach
or surpass those of industrial sources in many cases ie.g., Port-
land, Oregon) argues strongly for shifting some pollution control
tax credit resources to address RUC.
Another potential hurdle in implementing the testinq/cer-
t.ficacion approach are possible difficulties ~,:. enact i ,,., le^cl
autncrity to prohio'it coi..,;;ercial sales of nor-cer.; f \c^ j..rr;i;r_,
units.
2. Least Cost Emission Reductions
uased on tlie analyses (and assumptions) in this report,
a jroup of strategies emerge which potentially offer significant
RWC emissions reductions, with minimal cost and inconvenience,
and high public acceptance. They would appear to offer by far
the most substantial RWC emissions reductions, at the least cost
- especially if they are implemented in combination, as explained
4,
below.
There is one major caveat - the estimated emission reduc-
tions from these strategies have high uncertainty for two reasons.
First, their research basis is thin. Second, they rely on public
information to change RUC practices, and human behavior is notably
uncertain and difficult to predict.
The strategies with their estimated R'.JC emissions reductions
in parenthesis include: encouraging larger firewood piece size
(11.5%), moisture content ( 6.2%.), stove sizing (7-10%), and;
episode controls (33% on episode days). All are based on public
education. The first three could be jointly implemented with
annual administrative costs that are modest (estimated less than
5100,000 in Appendix F) compared with the other strategies evalu-
ated here. The combined emissions reductions of these three
strategies is 23% by about 1990 [(1.0 - .062)0.0 - .115)
(1.0 - .07} = .77]. This surpasses both of the top ranked
VI-25
-------
(testint/certification/ strategies, which are estimated to achieve
12-17% eiiiissions reductions by 19SO at twice the cost, or ir.uch
higher, if tax credits or other financial incentives are offered.
However, the equations used to estimate emissions reductions
from all three strategies are based on limited lab tests uy a
single researcher (different in each case), although the general
phenomena may have been ooservec by several researchers. These
strategies are thus pri^.e candidates for further research to
determine whether they really oo offer the .nost cost-effective
r<,-;C controls.
3. Research and Development
Despite the fact that no emission reduction estimate could
be made for this strategy, it still ranked highly (5th overall)
in the Keppner-Tregoe process. It is the key which could open
the door to emission reductions from a wide range of strategies.
This point is illustrated in the section above which discusses
educational strategies to change operating practices. These
strategies may well be the most cost-effective strategies for
reducing RWC emissions over the next 10-20 years, but additional
research is needed to verify this.
Of all research and development funding categories, the
greatest need appears to be for the development of simpler and
less expensive emission measuring techniques for RWC. This would
facilitate not only testing/certification or testing/labeling
strategies, but also help researchers refine the basic equations
which describe how RWC emissions are affected by key variables
such as moisture content, piece size and charge size.
4. Emissions Testing/Labeling Strategies
Three testing/labeling strategies (#3,#4, and #5) ranked 8th,
4th, and llth respectively in the overall WANT criteria ranking.
VI-26
-------
r.ll offer potentially significant emissions reductions oy I'^C-
k.^CC. Tne largest <-ecuctior. occurs with a significant financial
incentive (33% tax credit) which also greatly increases the program
costs.
The emissions reduction benefits are significantly less
tnan those froir, Strategies .?! and #2 which restricted sales to
certified units only. This dramatic limitation on consumer choice
was at once a major strength and liability for the testing/cer-
tification strategies. The three testing/labeling strategies
preserve consumer choice. In so doing they are likely to woe
ir.uch less effective in promoting the purchase and installation
of stoves -emitting £5 g/ky. Even with the tax credit jption,
there are likely to be cheaper stoves available with much poorer
emissions characteristics.
5. u'eatheriza'cion
The two weatherization strategies mandatory weatherization
for all households (#6), and mandatory weatherization only for
households purchasing new stoves (#7) were ranked 9th and 12th.
Both were judged to have relatively poor public acceptance due
to their mandatory nature, and high initial cost (despite eventual
"payback" through fuel savings)..
In the short-term, weatherization of a household may not yield
an emission reduction equivalent to the reduction in heat (Btu)
requirements, because 1) the operator may continue to burn as
much wood as before and rely less on conventional fuels, 2) the
operator may burn at a slower burn rate with a higher emission
factor, and 3) most operators will not immediately replace their
existing stove with a smaller less-polluting unit.
In the longer term, when the owner of a weatherized home
replaces his existing stove, additional emission reduction
benefits may occur, if a sizing education program convinces him
VI-27
-------
to ^urcliase a smaller stove, v.hich generally wi 11 have a lower
particulate ei,,ission factor.
6. Public Acceptance
The strategies rated n.ost acceptable to the public at large
unG LO l':l;C households in particular generally /vere those involving
u,u least 'inconvenience anc/or costs. For example, Strategy
rlO (increasing firewood piece size) ranked third overall, with
the highest possible scores in "public acceptance" and "minimizing
consumer costs". It costs individuals nothing, and reduces the
,,'ork of splitting wocu, while affording significant (11.5/i)
estimated emissions reductions.
The labeling strategies (#3, fM, and #5) ranked next highest
in public acceptance. They provide information which helps the
consumer choose a new stove, without limiting his choices or
raising stove prices. The version with a subsidy (Strategy #4)
ranked highest of these three.
Ranking similarly high in public acceptance were moisture
controls (Strategy #8) and stove sizing (#9). Both provide infor-
mation and rely on voluntary compliance with little or no enforce-
ment pressure (stove sizing involves an installation permit review
process). Episode controls (Strategy #12) which ranks almost
as high in public acceptance, also would rely on voluntary compli-
ance except under very severe pollution levels.
Research and development easily ranks high in public accep-
tance, offending no one.
7. Lowest Ranked Strategies
The strategies which ranked last under the Keppner-Tregoe
analysis were fireplace underfire air and periodic inspection.
Fireplace underfire air has been reported to reduce emissions
by 40%, but this is based on a single lab test. This strategy
VI-28
-------
cojs ,,_,: '..t..JrLSG In:. K.r5osc category of i;';.'C .en'1 ssions at all
- s"cov_ ti,; i ss i j;.s - coo it applies only to new fireplaces. It
was not assumed to have high public acceptance.
Periodic inspection, although it has significant safety
benefits, was not assumed to have any certain emission reduction
benefits in most cases. Tiic inspection strategy appeared likely
to M<:V_- ... issi'jn r&cuctijM potential only in areas with t; tr.sr
1 ; e ;,i_,r. fraction of Catalyst stoves (catalyst lifetimes are
about 2 years;, L) a hibi. fraction of new technology hi.jh effici-
ency uri.t:- ,;.iore sophisticated units may be r.iore likely to neec
h.air.teriajice to ,'c.intain !ngh performance), or 3j a limitoc riUmber
of stove models, since inspectors then would have greater potential
for recognizing relatively poor performance and maintenance needs.
Periodic inspections was assumed to have poor public acceptance.
VI-29
-------
VII. REFERENCES
Residential Solid Fuels: Environmental Impacts and Solutions,
Proceedings of the 1981International Conference on this topic,
held June 1-4, 19G1 in Portland, Oregon U.S.A.. Edited by Dr.
John A. Cooper, sponsored by the Oregon Graduate Center, 3eaverton,
Crc^on. The following papers presented at this conference are
referenced in this report:
a. S.A. Carlsson, "Residential '..'ood Combustion in Sweden -
Environmental Aspects and Regulations", pp. 1160-65.
L.ic. Pullen and R. Holden, "Design Features arid Test Experi-
ences with Domestic Wood Fired Heaters in i'iew Zealand",
...... 1106-7S.
c ,art in, "European Experiences and Activities in Assessing
the Environmental Impacts from Wood Combustion^' pp. 1180-9G.
d. P.b. i-iachlin, "Residential Solid Fuels in the Environmental
Protection Agency Region VIII States", pp. 1197-1215.
e. J..<'. Phillips, J.R. Duncan, and B.L. Barnard, "Regulating
Residential Biomass Combustion in the Tennessee Valley Region"
pp. 1216-28.
f. U.T. Greene and B.J. Tornbleson, "Institutional and Regulatory
Approaches to Control Residential Wood Burning Emissions",
pp. 1229-52.
g. T.A. Hors, T.T. Blair, and R.H. Cole, "Regulatory Options
for Controlling Emissions from Combustion of Wood in Residen-
tial Applications", pp. 1253-71.
h. R. Dickinson and R.C. Payne, "United Kingdom Efficiency Tests
and Standards for Residential Solid Fuel Heating Appliances",
pp. 1055-88.
i. S. Barnett and D. Shea, "Effects of Wood Stove Design and
Operation On Condensible Particulate Emissions", pp. 227-266.
j. J.F. Kowalczyk, P.B. Bosserman, and B.J. Tonibleson, "Particu-
late Emissions From New Low Emission Wood Stove Designs
Measured by EPA Method V", pp. 54-78.
k. J. Shelton, "Thermal Performance Testing of Residential
Solid Fuel Heaters", pp. 1117-59.
VII-1
-------
}. L. Rudling, R. Ahling, and G. Lofroth, "Chemical and Li
Characterization of Emissions froir Combustion of U'ooci ana
i.ooci-chips in Small Furnaces and Stoves", ^p. 54-53.
i,i. W.:;i. Cooke and J.i-i. Allen, "Characterization of Emissions
From Residential Wood Combustion Sources", pp. 139-163.
;;. J.F. ,\o',,alczyk and ',,.T. ^reene, ";iew Techniques For Identifying
Mi.,bient Air Impacts from Residential '.-iood Heating", pp. 459-494
_.. r'.L.Dcle, oca! , "ilxpt:rv,.'.entul measurements of Emissions
frui., Residential -.\ood-uurninc, Stoves", pp. 79-138.
K. 5. Darnett, "Determination of wood Stove Efficiency Under
In-Home Conditions", pp. 996-1037.
"Findings and Recommendations for a Particulate Control Strategy",
adopted by the Jackson County (Oregon) Board of County Commis-
sioners, fiovember 1981.
3 Del Green Associates, Inc., Residential Wood Combustion Study: Wood Fuel
Use Projections, (Task 3), November 1982.
4. "State Implementation Plan for Total Suspended Particulate for
Portland-Vancouver Air Quality Maintenance Area (Oregon Portion),
Oregon Department of Environmental Quality, November 1981.
5. Personal Communication with Jeanne McCormick, Portland Energy
Office, February 1982.
6. Weatherization Ordinance No. 18757, City of Eugene, Oregon, adopted
February 1981, effective date January 1, 1985, and explanatory
memorandum from the Eugene City Council.
7. Pacific northwest Electric Power Planning and Conservation Act,
P.L. 96-501, December 5, 1980.
3. Keppner, C.H. and Tregoe, B.B., The Rational Manager. McGraw
Hill, 1965.
9. Appendix A of report by FMC, Inc. to Oregon DEQ,' entitled
"DEQ - State of Oregon Field Burning".
10. "Proposed Amendments to t4issoula City-County Air Pollution Control
Program", provided to the Oregon Department of Environmental
Quality (Portland) by Mr. Scott Church, Missoula City-County
Health Department, 301 West Alder, Missoula, Montana 59802,
January 19, 1982.
11. Orecon DEQ, Herlyn Hough, "Status of Particulate Strategy Recom-
mendations (for the Medford-Ashland AQMA)", June 15, 1981.
VII-2
-------
12. Oregon devisee; Statutes 468.290(5):
13. J. She"! ton, The '..'oociburner' s Encyclopedia, Vennont Crossroads
Press, 1B75.
14. J. Shelton, Measured' Performance of Fireplaces and Fireplace
Accessories, 197S, Shelton Energy Research, PO Box 5235,
Santa Fe, New Mexico S7502.
15. Personal Coini.iuni cation with Stockton Barnett, March 1932.
1C. J. Shelton and C. Lewis, "Testing Creosote-Reducing Devices:
The Results" in Mother Earth News, March/April 1982, pp. 120-134.
17. PEUCo Environmental, Source Testing for Fireplaces. Stoves, and
Restaurant Grills in Vail, Colorado, prepared for U.S. Environ-
mental Protection Agency, Region VIII (Denver), by PEDCo cnviron-
,,entcl, Inc., 24oO Pershing Road, Kansas City, Missouri 54100.
IS. 5. Butcher and E. Sorenson, A Study of Wood Stove Particulate
Emissions, Journal of the Air Pollution Control Association (JAPCA)
Vol. 29, No. 7, pp. 724-728, July 1979.
19. Personal Communication with Gerald Grisvold, Anchor Tools and
l.'ood Stoves, harch 1982.
20. Del Green Associates, Inc./OMNI Environmental Service, Residential Wood
Combustion Study: Emissions Testing of Wood Stoves (Task 5), November 1982,
21. Personal Communication with Robert Harley, Albuquerque Air
Pollution Control Division, Albuquerque, New Mexico.
22. Personal Communication with Scott Church, Missoula Air Pollution
Control Agency, Harch 1982.
23. Larseri, Techniques for Evaluating Peak to Mean Pollutant Concentra-
tion Ratios, 1973.
24. Personal Communication with Bill Day, Anchor Tools and Wood Stoves,
March 1982, (503-223-3452).
25. Oregon Department of Commerce, Office of the State Fire Marshall,
Executive Summary of Oregon Fire Experience During 1979, 1981.
26. Personal Communication with C. Loomis, Corning Glass Works at
the February 1981 Wood Heating Alliance Conference in Louisville,
Kentucky.
27. Personal Communication with J. Kowalczyk and D. Tombleson, Oregon
Department of Environmental Quality, March 1982.
VII-3
-------
._>,. -'crsoriul Con.i,.unicacion witn Cedr-.c Sanborn, Vermont Air Pollution
..v-rtrol Prot,ra,,., February 1932.
L.'^ . 'uregcn Depart,r.ent of Environmental Quality, Description of Oregon
Method 8, undated.
^. J0tul U.S.A., Inc., Efficiency Test Results fcr the Jtftul
OJC.-1 201, 19o2.
- Del Green Associates, Inc., Residential Wood Combustion Study: Wood
Feul Use Projection (Task 3), December 1982.
.recon Revised Statutes 463.155 et. seq.
"_ c/ii, Johnson, and Uciell, Portl and Growth . :anage;:ient Study,
<,.jorcJ for Lnc City of Portl and Under 'J. S. £?A Funding,
i ~ ^ ~j
-.f :u c.1 j i ^0 1 .
34. Del Green Associates, Inc., Residential Wood Combustion Study: Technical
Analysis of Wood Stoves (Task 4), April 1982.
l~ . 3. Butcher and 0. Buckley, "A Preliminary Study of Particulate
[Missions from Small Wood Stoves", JAPCA Vol. 27 No. 4,
r;p. 34G-348, April 1977.
3o. Personal Conanunication with K. Davis, Sav-Mor Insulation Company.
J7. Oregon Cepartiiient of Energy, Iv'eatherization, One Step At A Time,
I960.
3u. John Hazen, Oregon VJood Heat Hand Book, 1981, Keylock Press,
PO Box 7514, Salem, Oregon97303.
31. T. naxwell, D. Dyer, and G. Maples, Studies of Creosote and
Chinineys at the Auburn Woodburning Laboratory, September 1979.
Del Green Associates, Inc., Residential Wood Combustion Study: Residential
Household Survey (Task 2B), February 1982.
41. Oregon Department of Environmental Quality, 1981 Medford Wood
Usage Survey, December 1981.
41. Albuquerque Air Pollution Control Division, Robert Harley,
Air Pollution Signal Light Demonstration, February 15, 1982.
43. i-iissoula City-County Health Department, Amendments to Mis sou la
City-County Air Pollution Control Program, 1982.
44. Missoula City-County Health Department, "1980 Missoula Air
Pollution Survey", published results dated December 19, 19GO.
VII-4
-------
Personal Coini."cft ^roposec ASr.il^E Standard 1C6P, publishc-c,
January 7, liou, :>y ihe Aiiiericon Society of Heating, i;efr ; oerat", '
and Air-Conditioning Engineers, Inc., (ASHRAE), 345 E. 47th Street
,,e\.; York, New York 10L17.
ol . "Residential Coal burning Evaluation: Strategies, Emissions,
Impacts", prepared for FJew England States for Coordinated Air
Lse iianageiiient, Boston College, Weston, Mass. 02193, by
;..T. Green, President, Solutions for Energy and Environment, Inc.,
1515 ilW 23rd, Portland, Oregon 97210, September 15, 1981.
jiL. '",,'ood Stove Smoke", article in The fiother Earth News,
iioveuber 1981, pp. 72-74.
b3. "State of Oregon Policy Developed by Office of State Fire Marshall
and Building Codes Division for Solid Fuel Burning Appliances,
published December 1979 by Oregon Department of Commerce .
54. PEDCo Environmental, Inc., A Review of Existing Air Pollution
Control Ordinances in Four Colorado Ski Communities, prepared
for U.S. EPA Region VIII (Denver), by PEDCo Environmental, Inc.,
2480 Pershing Road, Suite 110, Kansas City, Missouri 64108.
55. Oregon DEQ, "burn '.Mood Better", brochure published in 1981.
VII-5
-------
APPENDICES A thru F
Appendix A - Keppner-Tregoe Evaluation Process
Appendix B - RWC Control Strategy Elements
Appendix C - Ranking RWC Control Strategy Elements
vs WANT Criteria
Appendix D - Estimated RWC Emissions Reduction Potential
of Generic Control Strategy Approaches
Appendix E - Ranking Final RWC Control Strategies
vs WANT Criteria
Appendix F - Selected Costs and Benefits of
Final RWC Control Strategies
-------
APPE.JL'IX A
Keppner-Tregoe Evaluation Process
This appendix describes: the reasons for selecting the MUST
criteria and some of the WANT criteria used in this analysis
(Section I), and; the method of paired comparison used to assign
weigh
ing Factors to ;Mi;T criteria (Sec nun II
I. .-.US! AND i.AfiT CRITERIA RATIONALE
In establishing MUST criteria, several seeded automatic -- e.g.,
reduction of RWC pollution impacts, confon.iance tc Clean Air Act
requirements, and maintenance of safety characteristics of RUC appli-
ances. The Clean Air Act requires areas which exceed ambient air
quality standards to be addressed in State Implementation Plans (SIPs).
SIPs must propose enough emissions reductions from point and area
sources to achieve compliance with the Ambient Air Quality Standards.
Adequate legal authority to control these targeted sources must be
demonstrated in SIPs. Accordingly, control strategies considered in
this analysis should either be implementable under existing state or
local legal authority, or any needed changes in state statute or local
ordinances should be acknowledged.
The effectiveness of a proposed strategy must be documentable
for SIP purposes, including quantitative estimates of emissions reduc-
tions. To make significant reductions in emissions from the areawide
RWC source, a strategy must be widely applicable - i.e., it must affect
a significant portion of all wood burning practices or appliances.
Furthermore, it should be implementable within a relatively short time,
in order to minimize either the purchase of inferior new or replacement
RWC appliances, or the prolonged continuation of inferior RWC practices.
An exception to this would be a strategy with very significant long-
term benefits. As already mentioned, any changes in RWC appliances
or practices to reduce air pollution cannot be made at the expense
of safety factors.
A-l
-------
Consequently, the l.uST criteria presented in TabVe 1. DT the report
text were selectee! for use in evaluating proposed RWC air pollution
control strategies.
WANT criteria can and should include some MUST criteria, or
aspects of MUST criteria. This allows evaluation of the extent to
which some strategies will satisfy these important criteria better
than other strategies. For exanple, MUST criteria £1 (Table 1} rec^u'ir'js
that proposed strategies reduce RWC air pollution impacts. '..'ANT
criteria #1 and #2 (see Table 2) reflect how well proposed strategies
reduce RWC air pollution by evaluating how well each proposes strateu;.
<-oes two things: 1) reduces the average amount of RWC emissions ,.t r
household, and; 2) discourages new RWC households, or encourages
existing RV.'C households to stop RUC.
Use of WANT criteria #2 does not imply that strategies shoula
be designed to discourage RWC activity itself. This would undoubtedly
be widely viewed as unwanted intrusion by government upon individual
freedom of choice. Also, states like Oregon expressly exempt individual
households from direct state agency regulation of air contaminant
12
emissions. This criteria is simply an appropriate parameter for
evaluating the effects of a given strategy, in discouraging new RWC
households or encouraging existing RWC households to discontinue RWC.
The most effective RWC control strategies will be those which
effect maximum reduction of RWC emissions with minimum impact on
individual freedom of choice, cost, and inconvenience i.e., with
maximum public acceptance. Accordingly, a WANT criteria U4) has been
included to evaluate public acceptance of proposed strategies. It
is intended to indicate several different things. One is the antici-
pated public perception of whether a proposed strategy'is .an appro-
priate, or at least tolerable, level of regulation for dealing with
air pollution problems related to RWC. Another is the anticipated
acceptance by affected individuals of whatever inconvenience the pro-
posed strategy might cause them. Inconvenience here means extra work,
not costs which are covered under WANT criteria #6.
A-2
-------
The perceived costs of installing and using f^C are likely to
be the overriding factors influencing individual consumer excisions.
27
A University of Idaho study found that the main reason given by people
28
for using RWC was to "save money". A Dartmouth study which modeled
flew England wood fuel use, portrays the price of wood and conventional
fuels as the most influential factors in promoting or suppressing RWC.
Proposed RWC strategies which exert their effect by making RV-'C ,r.ore
costly liiay be the Most effective strategy of all. however, strategies
which force large added costs on RWC users could generate significant
political opposition. Accordingly, strategies ,;hich obtain significant
U'nC emissions reductions while ,111 niini zing added consumer costs are
preferred.
Many WANT criteria could be based on cost considerations. For
example, separate WANT criteria could call for minimizing capital costs
and operating costs of RWC to homeowners; minimizing similar costs
to RWC appliance manufacturers; and minimizing agency costs to regulate
RUC. However, if too many WANT criteria were based on various RWC
costs, combined with the separate estimates of strategy costs called
for in Step #6 of the overall evaluation process, too much weight might
be placed on cost factors, or cost considerations might be too heavy
in the wrong part of the strategy evaluation process. Accordingly,
recognizing the strong influence of consumer cost on RWC control
strategy effectiveness, a single WANT criteria i#§) is included, based
on consumer costs. It is intended to represent the assumption that
the more a proposed strategy increases the consumer costs of RWC, the
more it will discourage RWC altogether. It also assumes that increased
costs incurred by the private sector, as a result of a proposed
strategy, will be passed on to the consumer.
Agency costs of regulating RWC are a consideration under WANT
criteria #9, which deals with the administrative feasibility of pro-
posed RWC control strategies. Other considerations under this criteria
include the degree to which proposed strategies: a) could be
implemented rapidly, b) conform to Clean Air Act and EPA requirements,
A-3
-------
c; have effects which can be documented for purposes of inclusion -n
State Implementation Plans (SIPs), c) can Lie accepted (i.e., not
strongly resisted) by regulated parties, and e) require willing par-
ticipation by key parties which might not be forthcoming -- e.g., low
interest loans by financial institutions to subsidize home weather-
izat ion.
Other '.,'AiiT criteria address whether proposed control strat^ e.:
a] discourage the use of the worst polluting UWC appliances or
practices, b) utilize proven technology or encourage innovative tech-
nology, c) are widely applicable to RwC appliances or practices, o.
Minimize interference in the free .r.arket, and e) promote energy con-
servation and use of less polluting renewable energy resources, and
f) have minimal probability of circumvention. In this report use of
renewable resources is meant to exclude the promotion of wood fuel for
RWC, because this would contradict the purpose of RWC control
strategies.
Table 2 in the text presents WANT criteria selected for use in
evaluating proposed RWC control strategies.
II. WEIGHTING FACTORS FOR WANT CRITERIA
An analytic tool called paired comparison was used to develop
Weighting Factors for all WANT criteria. In this technique, each WANT
criteria is paired with each other WANT criteria separately. For each
pair a judgement is made as to which criteria is most desirable or
iinportant. Then a score 1-3 is given to represent their relative
difference in importance using the following scheme.
-t
Relative Importance Score
Little Difference 1
Some Difference 2
Great Difference 3
A-4
-------
Figure Al is a worksheet showing the results of the-paired com-
parison analysis of tiie 12 ;.-;AuT criteria listed (Table 2 in the text)
above. In each box, the letter refers to the WANT criteria considered
most important in that paired comparison. The number in each box is
the score indicating the difference in importance of the two criteria.
Scores are suuned for each WAiJT criteria (letter), and converted into
,.e iyiitin^ Factors, as shown in Figure Al . For the 12 1-iANT criteria,
.,C'"iijhti r.5 Factors will range frorr. 1 to 13.
A-5
-------
FIGURE Al
Paired Comparison Work Sheet
WANT Criteria
Reduce RWC emissions/household
Reduce No. of RWC households
Maximum public acceptance
Minimum consumer cost
Discourage Worst Appliances/Practices
Maximum agency admin, feasibility
Use proven technology
Encourage innovative technology
Widely applicable
Minimize free mkt. interference
Promote conservation/renewables
Minimize Circumvention
Total Points (125)
Fraction of Points
Factor Ranking
Weighting Factor
A
B
C
D
E
F
G
H
I
J
K
L
Al
Al Bl
A2 B2
A2 B2
A3 B2
A3 B3
A3 B3
Al Bl
A3 B3
A3 B3
i\2 B2
A B
23 22
Cl
Cl
C2
C2
C2
Cl
C3
C3
Cl
C
15
E2
02
01
02
11
D2
D3
LI
D
10
E2
E2
E3
11
E2
E3
El
E
15
Gl
Fl
12
Fl
F2
LI
F
4
G2
12
G2
G2
Gl
G
8
13
HI
HI
L2
H
2
13
13
12
I
17
Jl
L2
J
1
L2
K
0
f
1
<
L
8
Instructions
For each pair of WANT criteria com-
pared, place the letter of the -more
important criteria in the.square,
followed by one of the following
scores, based on an assessment of
the difference in importance of tne
two cri teri a .
Score
1
2
3
Li ttle Di fference
Some Difference
Great Difference
Sum the total points scored for
each WANT criteria (letter)',
calculate Weighting Factors.
r-li-ii-HO'-tOOO'-'OOO
1 2 4 6 4 9 7 10 3 11 12 7
13 13 9 6 9 3 5 2 10 2 J 4
A-6
-------
APPENDIX G.
Rl'.'C Control Strategy Elements
This appendix lists the seventy-five RWC control strategy elements
compiled for initial screening and evaluating, organized in the
folio/ring fon.iat:
I. Strategies to reduce emissions by improved burning unit design
II. Strategies to reduce emissions by reducing wood usage
III. Strategies to reduce emissions by focusing on operating
procedures
.-,'ithin these categories, strategies can be organized by the rnethoas
of achieving these strategies, namely:
A. Regulations requiring compliance with various wood burning
rules
B. Market incentives to achieve the strategies
C. Information distribution/technology transfer to speed
development and implementation of strategies
I. BURNING UNIT DESIGN
A. Regulations
1. Government-required certification programs which set burning
unit emission standards.
a. For new installations
b. For existing units (retrofits)
2. Government required rating programs under which woodburning
units sold must be rated for emissions.
B-l
-------
^. i,arket Incentives
1. Government subsidies for purcnase of cleaner burning units,
a. Subsidies to purchasers
1. For new installations
2. For existing installations (retrofits)
2. Variable subsidy proportional to clean burning
characteristics
4. Subsidy of X amount for all units cleaner than
certain emission rate
b. Subsidies to manufacturers
1. Increased tax advanta^..-:; fo' cessions related
research
a. Basic research
b. Pollution measuring equipment only
2. Increased tax disadvantages for companies in
proportion to the increasing pollution character-
istics of their burning units.
c. Sponsor design competition with $50,000 prize to
first designer of a burning unit that costs less
than $1000.00 (commercially) and emits at a rate
' less than 1 g/kg.
d. Offer $50,000 prize to first designer of a test
procedure system that costs less than $100.00 per
test.
C. Technology Transfer
1. Government agency provides funds to help reduce the cost
of emissions testing.
a. Free fully-staffed testing facility
b. Tax credits on emissions testing equipment and/or
services
c. Funds to develop standardized, simplified and less
expensive emissions test procedure (now $2000
per test)
B-2
-------
Trace Association emissions rating program
a. Voluntary program for submitted burning units
b. Mandatory program wherein all trade association
members must submit to testing on all models
c. Mandatory program wherein a manufacturer can only
participate in the program if all unit types produced
by the manufacturer are tested
Disseminate design information
a. Government funds to publish one-time or periodic
updates on burning unit design considerations/research
b. Trade Association funds to publish one-time or
periodic updates on burning unit design considera-
tions/research
II. REDUCING WOOD USAGE
A. Regulations
Weatherization requirements so heating requirement is
reduced.
a. Allow new installations only in dwellings which are
highly weatherized
b. Require all dwellings to be weatherized to a cost
effective level (5-7 years payback) within 5 years
or after resale (as in the Portland Energy Policy)
c. Tax credits from government to offset some
or all of the costs.
d. Require utilities to assist in paying for
weatherization.
Limit access to wood from federal lands.
a. Environmental Impact Statement requirement - Require
the USFS and BLM to conduct an environmental impact
assessment of the air quality consequences of their
B-3
-------
releasing inexpensive wood which when burned in urban
areas, can in aggregate constitute the single largest
source of particulates.
b. USFS/BLM limits on wood use
1. Allow only X cords cut per year based on air
quali ty
2. Allow only X cords per cutting permit (e.g.,
2.5 cords rather than the 4+ cords which uright
be needed to heat a poorly insulated house,
3. Stacger wood cutting periods to help assure
ciryiruj of wood
3. Emission density zoning.
a. Allow only X burning unit installations per square
mile based on area dispersion capacity
b. Allow only X cords of wood to be burned per square
mile based on area dispersion capacity
4. Burninc, unit efficiency
a. Allow new installations only if unit will provide
a net substantial heat gain (likely implies glass
doors for fireplaces)
b. Efficiency certification-allow new installations
only if unit efficiency exceeds certain requirements
Market Incentives
1. Government subsidies for weatherization.
a. Only in areas with severe pollution potential
b. In all areas
2. Increase wood prices to residential users.
a. Subsidie.s for industrial use of wood to enable
industrial users to outbid residential users for
available wood
b. Increase USFS/BLM wood cutting permit fees
B-4
-------
3. Increase the cost of wood heating.
a. Increase hoi.ie tax assessment value if home has wood
burning units
b. Insurance company fire insurance rates
1. Urge insurance companies to adjust home fire
insurance policy rates in proportion to ^/nether
.-.ood heat is used and unit has been recently
i nspected
2. Urge state insurance commissioners to require
above action
4. Reduce prices of conventional and alternate fuels.
a. Lifeline electricity rates
b. Lower residential gas rates
c. Lower residential oil rates
d. Subsidies for solar energy use
Information/Technology Transfer
1. Disseminate efficiency information on burning units.
a. By government agency
b. By trade association
c. By neutral research organization
2. Economics.
a. Make public aware of true cost of wood heating
b. Suggest to households that they limit fireplace usage
to 10 occasions per season as a compromise between
aesthetic use and avoiding heat loss
3. Health concern - make public aware of indoor air pollution
consequencies of wood heating.
4. Safety Concern - make public aware of frequency of fires
associated with home wood burning so as to discourage
use.
B-5
-------
5. Promote alternate radiant heat sources.
a. Promote natural gas fireplaces with greater visual
simularity to wood fuel and therefore greater
consumer appeal
b. Promote (clean) natural gas radiant space heaters
c. Promote passive solar usage
6. Promote wearing warm clothes indoors.
7. Heat key areas selectively.
III. OPERATING PROCEDURES FOR WOOD BURNING UNITS
Technical chimney sweep program -- test emission rates
on-site.
a. Opacity
b. Mass of parti culates
c. Simple carbon measurement
d. Carbon monoxide measurement
Government authority to require cutbacks in wood usage
during peak pollution periods.
a. Instantaneous - based on nephelometer or automatic
particle monitor measurements
Sizing of Burning Units.
a. Government agencies require manufacturer to state
on unit how much space can be heated with the unit
for living space insulated to certain assumed levels
Moisture Content.
a. Require all commercial v/ood sales to" include infor-
mation on average moisture content
b. Limit free wood cutting on public lands to time
periods (likely spring/summer) which maximize the
probability that wood will be sufficiently dried
before use
B-6
-------
b. Market Incentives
1. Moisture content - government subsidizes a regional wood
drying facility.
C. Information/Technology Transfer
1. i'.oisture Content.
a. Educate wood users on the importance of moisture
content with regards to emissions and efficiency
1. Government publications
2. ilewspaper/television exposure
b. Distribute plans for low cost solar wood dryers
c. Distribute X free moisture meters to commercial wood
distributors
2. Distribute information on avoiding creosote build-up/
minimizing emissions.
a. Government employee activity (e.g., British Solid
Fuel Advisory Service)
b. Individual manufacturers distribute information
to users
c. Trade Association distribute information to users
d. Generate media interest and media reporting
e. Government agencies send latest information to manu-
facturers and distributors on how to minimize
emissions
3. Burning Unit Sizing.
a. Government agencies distribute information on impor-
tance of not over-sizing
b. Trade Associations develop program for rating how
much space can be heated with a given burning unit
4. Concerned Neighbor Approach.
a. Concerned neighbors or neighborhood association
members suggest to homeowners with smoky burning
units how they could burn wood with less emissions
B-7
-------
RanKing R'.;C Control Strategy Elements vs tv'ANT Criteria
Table Cl shows the overall ranking of each of the seventy-five
RWC control strategy elements (Appendix 8) considered in this study
versus the twelve '/.'Ai'lT criteria defined in Section III of the text.
The total scores in the second column of Table Cl are documented
in Table C2, which shows the individual scores assigned to each
strategy element for each WA!1T criteria. The identification number
in column three of Table Cl refers to the comprehensive listing of
all seventy-five RWC control strategy elements, in Appendix B.
Note that when similar control strategy elements ranked closely
in score they were combined in the Table Cl ranking. Thus, the
seventy-five control strategy elements were combined into fifty-four
ranking slots.
C-l
-------
I , ^ L L
i ho Gt I Iml V "i UUd 1 u..'C Jofit
vs
All .\Ai.T Criteria
Overal 1.
Rank
1
2
3
4
5
6
7
8
Total
Score
535
504
487
480
476
471
469
468
III
II.
I.D.
No.2
.A. 3
A.I. a
I. A.I. a
II.
II.
II.
I. A
III
A.l.b
A.l.d
A.l.c
.l.b
.C.S.a
7
8
9
10
11
12
From
469
468
465
459
453
447
Table C2
I. A. l.b
III. C.S.a
Ill.C.S.b
I. B.I. a. 4
I. B.I. a. 3
I.B.l.c
Description of Control Strategy Elements
Government requires manufacturers to label
stove as to space it can heat vs various
house insulation levels.
Allow new stoves only in highly weatherized
households.
Government required certification (vs emis-
sion standards) of new burning units.
Require all dwellings to be weatherized to
cost effective level within 5 years or after
resale.
Require utilities to help pay for weatherizing
households.
Tax credits from government to offset some or
all costs of weatherization.
Same as #3, but for existing units (retrofits).
Government distributes information on impor-
tance of not over sizing burning units.
Trade Association develop program for rating
how much space can be heated by a burning unit
(sizing).
Consumer subsidy to buy burning units cleaner
than an established emission rate.
Same as #10, but variable subsidy, proportional
to emissions rate.
Government sponsors $50,000 prize to designer
of first burning unit which 1) costs less than
or equal to $1000.00 and 2) emits less than or
equal to 1 g/kg.
C-2
-------
TABLE Cl (Cont.
Overall
Rank
13
14
15
16
17
18
19
20
21
22
23
24
Total
Score
437
437
436
424
422
418
385
416
410
415
407
404
403
401
392
395
I.D.
No.2
I.C.2.C
I.C.2.5
I.B.l.b
I. A. 2
III. A. 4. a
III. A.I. a
III.A.a.b,c,d
II.A.2.b
III. A. 4. b
II.A.4.b
II. A. 4. a
II.B.l.b
II. C. 2
I. B.I. a. 1
I. B.I. a. 2
I. C.I. a
Description of Control Strategy Elements
Mandatory emissions testing by Trade Assoc.
Mandatory emissions testing by Trade Assoc.
Tax disadvantage to companies proportional
to the emissions levels of their burning units
Government required rating of burning units
for emissions to allow their sale at all.
Require commercial wood sales to include
information on moisture content.
Chimney sweeps test household emissions.
Chimeny sweeps test household emissions.
Stagger federal (USFS/BLM) wood cutting
periods to help dry the wood - e.g., allow
cutting in spring or summer.
Stagger federal (USFS/BLM) wood cutting
periods to help dry the wood - e.g., allow
cutting in spring or summer.
Allow new burning unit only if efficiency
standards.
Allow new burning unit only if it provides
a "substantial net heat gain".
Government subsidizes weatherization in all
areas.
Make public aware of the true cost of wood
heating.
Consumer subsidy to buy cleaner (retrofit)
new burning units.
Consumer subsidy to buy cleaner (retrofit)
new burning units.
Government provides free fully staffed
testing facility.
From Table C2
From Appendix B
C-3
-------
TABLE Cl (Cont.)
Overal1
Rank
25
26
27
28
29
30
31
32
33
34
Total I.D
Score-'- No.
396 II.C.l.c
387
380
394
394
383
390
363
360
360
359
357
II.C.I.a
Il.C.l.b
II.B.S.b
II.B.4.C
Ill.C.l.b
III.C.I.a
378 I.C.l.d
364 I.C.3.a
358 I.C.S.b
II.B.4
I.C.2.a
II.A.3.a
I.C.l.b
I.C.l.c
Description of Control Strategy Elements
Disseminate information on burning unit
efficiency by neutral organization, govern-
ment, or'Trade Association.
Lower residential rates for gas & oil .
Educate wood users as to moisture content
effects on emissions and efficiency.
Educate wood users as to moisture content
effects on emissions and efficiency.
Government sponsors $50,000 prize for first
test procedure system costing less or equal
to $100.00.
Publish information on burning unit design
considerations/research by government or
Trade Association.
Publish information on burning unit design
considerations/research by government or
Trade Association.
Lifeline electricity rates.
Voluntary Trade Association emissions
rating program.
Emission Density Zone - allow only X burning
units per (mile)2 based on pollutant dis-
persion capabil ity.
Government gives tax credits on equipment or
services for emissions testing of burning units
Government funds development of standardized,
simpler, and cheaper emission test procedures
for burning units.
From Table C2
From Appendix B
C-4
-------
TABLE Cl (Cont.)
Overall
Rank
35
36
37
38
39
40
41
42
43
44
Total I.D.
Score* No.2
359 II.A.2.b.l
347 II.A.2.b.2
342 II.A.S.b
345 I.B.l.b.2.b
326 I.B.l.b.l.a
341 III.C.2.a,d,e
331 III.C.2.b,c
335 II.C.4
348 IH.C.l.b
315 III.C.l.c
310 III.B.
298 II.C.3
293 II.C.6
Description of Control Strategy Elements
USFS/BLM limits wood use to X cords/year
based on air quality (or, to "X" cords per
cutting permit).
USFS/BLM limits wood use to X cords/year
based on air quality (or, to "X" cords per
cutting permit).
Emission Density Zone - allow only X cords
burned per square mile, based on dispersion
capabil i ty.
Government subsidy to manufacturers of
burning units for pollution measuring
equipment (or, for basic research).
Government subsidy to manufacturers of
burning units for pollution measuring
equipment (or, for basic research).
Distribute information on avoiding creosote
buildup/minimizing emissions by government
or media (or Trade Association).
Distribute-information on avoiding creosote
buildup/minimizing emissions by government
or media (or Trade Association).
Make public aware of frequency of fires
associated with RWC, to discourage use.
Distribute plans for solar wood driers.
Distribute free moisture meters to commercial
wood distributors.
Government subsidizes regional wood drying
facility.
Make public aware of health concerns related
to indoor air pollution from RWC.
Promote wearing warmer clothes indoors to
reduce heating needs.
1
From Table C2
From Appendix B
C-5
-------
TABLE Cl (Cont.)
Overall
Rank
45
46
47
48
49
50
51
52
53
54
From
Total
Score*
285
283
275
283
271
273
264
304
238
273
252
235
234
225
211
Table C2
I.D.
No.2
Il.C.S.a
II.C.5.C
Il.C.S.b
II.B.2.a
II. B. 2.5
II.B.4.d
II. C. 7
II. B.I. a
III. A. 2. a
III. A. 2. b
II. A. 2. a
III.C.4
II.B.S.b
II.B.3.3
II. C. 2
Description of Control Strategy Elements
Promote alternative radiant heat sources -
e.g., natural gas fireplaces; passive solar;
or gas heaters.
Increase wood prices to decrease RWC by
subsidizing industry to use hogging residues
which would firewood; or, by increasing USFS/
BLM firewood cutting fees.
Subsidize solar energy as RWC alternative
Promote spot heating of key areas in house
(e.g., heat lamp in bathroom).
Government subsidizes weatherization but only
in areas with severe pollution potential.
RWC cutbacks during air pollution episode.
Require USFS/BLM EIS to assess air quality
effects of their firewood releases.
Concerned neighbor approach - neighbors tell
others how to reduce RWC emissions.
Increase cost of RWC by encouraging State
Insurance Commission or private carriers
to raise home fire insurance rates for RWC
households; or, raise property tax assessments
Suggest households limit annual fireplace
usage to 10 occasions to reduce heat loss
and emissions.
C-6
-------
TABLE C2
Keppner-Tregoe Scores for Individual RWC Control Strategy Elements vs All WANT Criteria
I. Burning Unit Design
l.AiiT Criteria'
1. Reduce RUC eciissions/liouseholc;
2. Reduce no. of RWC households
3. Widely applicable/effective !
4. Kaxin-ize public acceptance
5. Discourage worst appliances
6. Kiniuize consumer cost
7. Use proven technology
a. Kiniuize circumvention
9. Maximize agency feasibility
10. Encourage innovative
technology
11. Miniuize free uarket
interference
12. Proitote conservation and
renewable resources
..eijlit
Factor
13
1 3
K
^
L
I
4
;
->
\
A. ('emulations
I.A.I
-,~
- -
C,7
^ » *-
0 , '~j
3 ,3
6,5
C,C
1,1
1,1
6 ,6
2,1
I. A. 2
U
3
o
7
6
4
6
C
1
c
E;
i
J. i.urket Incentives
I. .!.,.
7,7,,:,.
i i i i
u,->,3,.
7,7.7.7
£,2,7,C
10, 1C, 1C, 11
C , G ,6 , 6
<;,5,5,5
5,6,6,5
6,5,7,7
2,2, 2, Z
2,C, 1,1
I.B.l.b
(4,4) C
(1,1) i
15,5) 6
15,;) I
;c,5) L
17, 3), C
!3,4J,6
(5,5),!.
(3,41,5
CJ.O.S
13, 2), 1
(2,2),C
I.b.l.C
<_
3
u
J
7
J
0
c
10
7
2
C. Technology Transfer
I.C.I
4,3,3.3
3,3,3,3
6,5,5,6
5,5,6,6
5,5,5,6
7,7,7,7
C.6,3,3
6,6,6,6
5,6,C,5
9.7.C.1C
7,6,7,7
2,1,1,2
I.C. 2
4,£,o
4,5,3
3 ,o,C
9,7,7
5,7.7
4,3,3
6,6,6
5,7,7
1,2,2
5,7,7
5,^,L
1,2,2
I.C. 3
3,3
3,3
2,2
'-,'-
4,3
L.C,
9,0
3,3
7,C
0,5
C,6
1,1
Criteria Scores:
487
459
424
401
392
326
345
436
447
395
359
357
3uu
437
437
11. Reduce Uood Usage .
UAKT1 Criteria
1. feeducc R*C t-wnsstons/
2. r.e) lances
o. i.innnZL- consumer cost
7. Use proven technology
o. llininilje circumvention
'J. Kaxiinizv ayency
feasibility
10. encourage innovative
technology
H. l.iniinlze free market
interference
Factor
13
13
10
j
S
C
^
3
2
2
1
i.S.C.C
i.9.4.4
3.9.6,6
3.1.5,6
7,7,5.5
3.0.10.K
7.3.G.S
1.1,5,6
4.4,4.4
2.6.2.2
7, 1!. 6, 5
2.14,3,6
4.10,3.7
2.17.7,6
5.13,3.4
1.15,5.6
t, 17. 7,6
C, 10, 0,0
3.11,1.4
3., 1.1.4
6.U.3.4
1. 12. 1.1
L.3
C,7
7.C
3.3
£.7
7,7
O.C
1,1
1.1
2,3
2.1
1.3
L,8
9..J
3.3
6.5
7,7
3.6
2.2
1,1
7.7
2,3
Market Incentives
11. E.I
5.0
3.3
5.6
3.7
5.6
0,0
o.u
1.2
5,6
4.4
3.2
5.6
n.s. 2
4.3
7.5
5,4
0,5
7,3
3.6
0,0
1.2
1.2
1.1
0.1
0.0
n.s. 3
1,11.1)
7,15.5)
5.14.4)
0.14.4)
3,13,3)
5,15,5)
U.(O.O)
1.12.2)
1.12,2)
1.11.1)
2. (3. 3)
1.11.1)
11. 6. 4
3.3.3.1
7. O.C. 5
5.5.5.3
6.8.6,5
5,5,5.3
0,10.10.
0.0,0.0
6.6.6.5
0,0.0,5
o.o.o.e
0.0.0.3
0,0.0.6
II. C.I | ' '
4,4,4
3.3.3
2.2.2
C.7,8
6,5.6
"8.8.6
8.8
4.4,4
7,8.7
6,6.6
8,8.6
6,5.6
11. C. 2
5.3
6.4
3,1
6,3
6.1
0,8
0,0
4.1
8.3
1.2
6.4
2.1
11. C. 3
2
6
2
6
4
7
0
3
5
1
6
1
Transfer
II. C. 4
4
6
2
6
£
8
0
4
5
1
6
2
11. C. 5
!.!.*
,,6.c
1,2.1
i.5,5
J.3, J
.,c,t:
3,0.0
1.4,3
1,3.3
I.1.C
!.2,3
1.0,6
11. C. 6
4.3
4,4
3.2
5.5
>.J
^
u,t
0.0
3.3
3.3
3.1
3,3
6,4
,.Ai!T Criteria Scores.
Ml :;'JST Criteria have been r.,ct.
504 252 3U)
460 35S 342
471 347
47S 416
407
415
304
<04
283
271
363
3S4
394
273
387
380
396
403
211
335
285
275
263
* Multiple numbers indicate individual scores for subheading under each control strategy as listed in Appendix B
For example, for WANT criteria 1 (8,8) indicates score of 8 for Strategy lAla and a score of 8 for Strategy lAlb.
Similarly, total scores of 487 and 469 listed at bottom of column are for lAla and IA)b, respectively.
C-7
-------
TABLE C2 (Cont.)
III. Operating Procedures
<' .T1 Criteria
.. lieduce RUC ei.jissions/householc
2. Rec-uce no. of !,;:C households
.. i-.'iclely applicable/effective
. XdxiL.ize public acceptance
5. Discourage worst appliances
i . i.irunize consumer cost
. jse proven technology
. :;inii,.ize circumvention
5. ..axu.ii 2e agency feasibility
3. Encourage innovative
technology
il. Himuiie free Market
interference
'2. Promote conservation in,l
4,4,4,4
t.C.C.6
3,3,3,3
5,5,5,1
7,7.7,7
", , 7 , 7 , /
7 , ^,6 , o
5, 1, 4, 4
4,4,4,4
6,6, 6,6
4,3.3,3
III. A. 2
1
f,
c
-
0
~.
J
4
3
<4
0
III. A. 3
2,
{
7
C
C
8
J
o
'J
7
8
5
III. A. 4
4,C
3,7
7,6
3,4
6,6
6, a
7,0
7,3
4,4
3,4
8,5
2,1
harket
III. J.I
1J
3
3
3
5
5
7
S
2
3
3
1
Technology Transfer
III. C.I
(5,51,4,3
(3, 3), 3, 3
(4. 3), 2, 2
(7, 7). 6, 5
(5,b),5,5
( 8 , 7 1 C , (J
{7,71,5,7
(3, 3), 4,1
(3, a), 2. 7
(3,3),u,3
(6,61,6,6
(1,1). 1.1
III.C.2
0,5,5,5,5
3,3,3,3,3
3,2,2,3,3
6,6,6,6,6
5,5,5,5,5
0 , C , (J ,b , O
0,0,0,0,0
4,4,4.4,4
7,7,7,7,7
5,5,5,5,5
6,6,6,5,6
1.1,1,1,1
ni.c.;
7,7
5 . -
4, J
S , ^
j,C
0 ,
-
'T ,
7 ,v,
6 , c.
7.7
4,3
1 1 '
C
i
;
:
(.-
I.
~ J Criteria scores:
413
3C5
385
3C5
273
535
422
410
310 390
303
343
315
341
331
331
341
341
465-
ill . ,UCT criteria nave
..eL.
* Multiple numbers Indicate Individual acore* for cubhcading under each control atrategy aa liaced in Appendix B.
For example, for WANT criteria 1 (8,8) Indicate* acore of 8 for Strategy lAla and a acort of 8 for Strategy lAlb.
Similarly, total scores of 487 and 469 listed at bottom of coluom are for lAla and lAlb. reapectively.
C-8
-------
Estimated [V.-.C Emissions Reduction
Potential of Control Strategy Approaches
This ,-^enci;; explains the Information anc assui .ptlon.s
,.tte;i,ptifK_ to quantify the potential reduction in air pel 1uU.r,t ;-. \->-
sions .
-------
i.,ethod'i,. TMs Hiethou captures uore condensable orcanics
than civ il.-v ,'Sthcd ^ ^roceotire with back-naif catc,-,,
Decause it utilizes an additional filter between the 3rd
and 4th impingers in EPA's Method 5 apparatus. Other
researchers have commonly reported stove emission in
the 1-97 g/kg range, but the average of thf 19 tests
conducted ir, Tasi-: C cf this study was 2'.. a/V.,. These d.f-
Tororices are liKely c^-j tv .1"; f forer.t sa..,h/r. r.^ pr-oc,
burr, rates, and sorr.e test procedures net incluciin., start-
up or.ii ssi ons.
n. t j r o v e u L- u r n i \ i ^ u r 'M L u e o < f >
This section reviews trie potential for reducina Ri,C particuKne
emissions through
1. luiprovec design of new stoves offered for sale including
analysis of the following strategy approaches.
a. Testing of wood stoves arid certification of compliance
with an estaolished emission limit as a prerequisite
for allowed sales.
b. Testincj/certification as a prerequisite of stove sales
plus financial incentive (33% tax credit) to buy the
cleaner stoves.
c. Testing/certification as a basis for mandatory labelling
which specifies stove efficiency and emissions perfor-
mance .
d. Testing/certification as a basis for mandatory labelling,
plus 33% tax credit.
2. Modifications of installed stoves, including-:
a. Air inlet modifications
b. Insertion of firebrick in stove box.
c. Fans to improve heat transfer.
d. Add-on particulate control devices:
1. Steel wool i;,esh filter
2. Catalytic afterburner
-------
3. Improved design or adc-&;i devices for fireplaces.
a. Underfire air.
b. Electrostatic precipitator
c. Glass doors.
Key Topic: Emissions Reductions Achievable by Advanced Design Stoves
iiew stoves of special design have achieved participate emissions
rates e.s low as 1-4 c;/kg of wood burned, as illustrated by four dif-
ferent designs describee here.
Refractory-lined, kater-Cooled, Turbulent Air Furance
The first system is a refractory-lined, water-cooled, tur-
bulent air furnace based on the design of Professor Richard Hill.
A furnace based on the Hill design, the Hampton-Jetstream, was
tested in 1980 by the Oregon Department of Environmental Quality
and was found to emit 3.4 and 3.S grams particulate/kilogram
wood in two separate tests. J
The principles which are thought to be responsible for
this unit's clean burning characteristics are: 1) the unit burns
very hot, enabling more complete combustion, yet still maintains
high thermal efficiency by extracting heat from the stack by
a water-cooling system; 2) turbulent air introduced improves
air-fuel mixing in the combustion zone allowing r.iore complete
combustion, and; 3) the water-cooling system also is used to
keep cool the area storing wood which currently is not burning,
which reduces "wood volatilization" prior to burning, and allows
a steadier fuel-air mixture to be maintained.
The unit has an overall efficiency (thermal and combustion
efficiency) of 79%, as tested by the manufacturer. However, it has
one major drawback - an installed cost in the range of $5000 to $7000.
J-o
-------
The units costs about $3500 without auxiliary plumbing. However, in
order to either tie into or construct a water-to-air heat exchange
system costs on the order of $1500 to $3500, raising the system cost
into the $5000 to $7000 range. Despite the high price which
limits this unit's applicability for most households, the low
emission rate which it achieves snows the potential for emission
rcductions.
Ceramic Stove
The second unit of interest is a ceran.ic stove tested under Task
- jf ,r;is contract. Test results showed that the unit emitted at 1
op
ur,u 2 ;,,'k.j in two different tests.
Tne chief drawback of this unit is its relatively low heat trans-
fer efficiency, which results in an average overall efficiency of about
5u%, ano its inability to allow an operator to control its burn rate.
Once fired, the unit burns wood in a hot and rapid manner, which is
not consistent with many wood user's desire for a slow and steady radi-
24
ant heat source. However, the fact that* this unit burns very clean
suggests that other units also can achieve this emission level. For
this unit, the application of some heat-exchanging mechanism between
the stove box and house chimney exit could substantially increase the
thermal efficiency, by storing some of the heat for release at a more
convenient rate.
Gasifying Stove
The third unit of interest is a gasifying stove, the Jotul 201,
to be marketed by Jotul beginning in April 1982. This unit has been
tested for efficiency and CO emissions but not yet for'particulates.
However, the efficiency and CO results suggest this unit also should
have low emissions of other pollutants. The gasifying stove is able
to more completely burn the volatilized wood gases by channelling them
to an upper combustion chamber.
-------
In tests at "low-output", which normally is the most difficult way to
burn with low emissions, the unit had a six-hour average CO stack gas con-
centrations of .05% of CO. This compares to CO levels of .2 and .4% for
the ceramic stove cited above during runs with particulate emission factors
of 1 and 2 g/kg. For "medium-output" and "high-output", the model 201 had
average CO concentrations of .28% and .69%. The very low CO levels at
"low and medium-output" are of greatest interest since people tend to operate
their stoves at low to medium burn rates. However, even though this CO data
suggests the unit will operate at a low burn rate with low particulate emis-
sions, the correlation between CO and particulate is uncertain. (During Task
5 of this study a correlation of .80 was found for CO and particulate con-
centrations but the data are limited.) This means that some stoves with low
CO emissions may still have high particulate emissions, and thus particulate
testing is needed to know the particulate emission rate for this stove with
confidence.
Overall efficiency for the 3 Jtftal tests conducted by the manufacturer
was between 75 and 78.5% and combustion efficiency for the three runs ranged
between 93.3 and 96.3% , which indicates that relatively complete combustion
was occurring. Until particulate emissions are actually measured, the real
emission rate cannot be known, but it seems likely to be in the 2 and 10 g/kg
range.
Catalytic Afterburner
Lastly, wood burning stoves with catalytic afterburners are available
which hold potential for reducing emissions by additionally combusting some
of the stack gas exhaust that would otherwise be emitted as particulate.
Although particulate emission testing on several catalytic stoves has not
shown any of these units to have significantly reduced emission characteris-
tics, research by several authors on efficiency suggests that catalysts can
help burn a significant (undefined) portion of the tars, vapors, soot, and
creosote that could otherwise escape up the stack.
Tor example, She!ton has reported overall efficiency increases
of 20% from about 50 to 60% net efficiency, and noted large temper-
D-5
-------
Lure J i f Parenti al s between locations above arid belov, the catalysl.
,-;v/,,Cv'er, reralj instol 1 iim a catalyst "wafer", through '!."ici; stack
air uiust pass in tne upper part of a stove's firebox does not guar-
antee -increased combustion efficiency or significantly reduced emis-
sions. To optimize complete combustion, the requirements of time,
temperature, .jood air-fuel ratios, and 9000 Mixing ;,,ust be r,iet. To
ai'o cr.tdlyst cor.ioustiori, secondary air likely is needed, but it i.>ay
n-jjc to be preheated to avoid quenching cc.;ibustiin< '< the catalyst
zone. Tne aiaount of secondary air supplied ,nust be appropriate for
the combustible content of the stack gas, and therf. , ust be sufficient
turbulence to promote yooc mixing of the introduce: i^e-c^ndcry air anc
t!)2 exhaust '-.ases. Catalyst stoves v.irich have balanced arid uptii:iizc-d
tnese different requirements in a specific design likely v;ill achieve
the Dest perforiaance. To this point, no specific catalyst stoves have
been shown to have substantially reduced particulate emission character-
istics, using either the EPA Method 5, the Oregon Method 7, or compar-
able emissions testing procedure. However, future optimization of
these requirements appears possible in a manner that could reduce emis-
*
sions by 75%, or more. At that point, the remaining problem will be
the length of catalyst life, and how to ensure catalyst replacement
at appropriate times (likely 2 years or less).
Based on this review of advanced stove/furnace designs, the fol-
lowing key assumptions are made, for purposes of estimating the poten-
tial emissions reductions achievable in the future from strategy appro-
aches which encourage the development and installation of wood stoves
designed to have minimum emissions:
Assumption: Wood burning stoves will be availab.le by January
1984 at a cost of $1200 or less, with particulate
emissions of 5 g/kg or less - i.e., 75% less than
the current estimated average emissions rate of 20 g/kg.
-------
T;,is ~^t>j is selectee, uecause it is two years forward from this assess-
ment of stovt. techno! oby, allowing time for a numoer of ,manufacturers
to follow up on designing units employing principles from the advanced
designs described above. Regarding the cost estimate, the last tnree
units discussed all cost less than $1000. Numerous manufacturers have
a^reec in personal conversations that if 6 burning unit .s developed
with hi^h i70-CO/J efficiency and low emission character, si ;-;s \.tt'''c'~,
costs less than 310Gu, it likely will be able to clai,, a lar.jt1 snare
of the r.iarket for new units. Thus even with inflation and design re-
search costs factored into stove/furnace prices, the above assumption
sfctMS reasuiia-jle. This assumption forms a key basis for esti,: at-rs
uescr",^eo Lelo1,,' of t'ie potential emissions reductions achievable by
four strategy approaches which assist anci promote the development and
installation of burning units with much lower air pollutant emissions
rates.
1. Improved Design of New Stoves
RWC emission reductions achievable were estimated for four
strategy approaches designed to promote development and installation
of cleaner burning wood stoves/furnaces. The following four strategy
approaches were analyzed:
a. Testing/certification as prerequisite for sale
b. Testing/certification as prerequisite for sale, plus a
33% tax credit for purchasing a certified unit
c. Testing/certification as basis for mandatory labelling
of efficiency and emission performance.
d. Testing/certification/mandatory labelling, plus a 33% tax
credit for purchasing a certified unit.
The following key assumptions were used for purposes of the
analysis:
L>-7
-------
vaseline F!',:C emissions one ,-,'000 fuel use i status L,UO, ",f
ic strctow ./as 1i..r;l or.';er,leu ; fcr ,,'<;. UL staves/furnaces fur
ll/vjC-UuG >,oulc je as describee in Figure ^1 ano Table ,1,
,,-iVicr' s.nov. the best est^ndte, loi.^-ier-.i trend For Portland,
^rjt3n fro, i Tas'r* 0 of tnis sti.'Jy.
The ;= coverage* assui.iec t:or the four strategy approaches
listed above, i.e., the % of new stove/ furnace purchases
which would be cleaner (certified) ourning units, is 60%,
90%, 20%, and 40%, respectively.
Certified stoves/furnaces which ,-ould emit 80% less parties
late than existing units (i.e., 4.5 g/kg), would be
i ally available by January 19C4 at a cost of SI 200.
Steve/furnace life (ave.j is 10 years, i.e., 10% of
existing units are replaced each year.
The four strategies analyzed in this subsection reduce KKC emis-
sions fro. n ,,'ood stoves and furnaces only. Table D2 summarizes the
stove/furnace wood usage {cords/year ) assumed for purposes of this
analysis, and the degree to which each of the four strategies woulo
result in the use of cleaner (certified) burning units. This is trans-
lateo in Table 03 into the emissions reductions available over time
,-rith each strategy approach.
In Table D2 the wood usage assumed is the best estimate of long-
term (1SBO-20CO) wood usage projected for Portland, Oregon in Task
3. These wood usage projections are shown in columns 2 and 3 of Table
D2 as the annual increase and cumulative total cords/year, respec-
tively. In columns 4 and 5 wood usage information is transformed into
index values using 1980 as a base year. That is, the 150,000
cords/year burned in stoves/furnaces in 1980 is given an index value of
100. All other wood usage data in columns 2 and 3 then is translated
into equivalent index values in columns 4 and 5. Since these index
values directly reflect RUC in stoves/furnaces, they also reflect the
relative number of stoves/furnaces in use, provided we assume that the
average wood usage (cords/year) in stoves/furnaces remains constant
throughout the analysis period (1974-2000). This assumption allows the
index values derived to represent relative wood usage to also represent
the relative number of stoves/furnaces in use in which this wood is
burned. Accordingly, index values also can be used to calculate the
relative number of certified and non-certified stoves/furnaces in use
in any year.
,- coverage refers to the percent of purchased u;\its which have
emission factors of 5 g/kc or less.
D-8
-------
FIGURE Cl
!3ase Case 157C to 2000 Projection
for
Portland Metropolitan Areas for Wood 'Usage
l.OE+5. 2.0E+5 3.0E+5 4.0E+5 5.0E+5 6.0E45 TF
1970 __S_ ------- -F-T ------ - --- - - -
. S .I' T ' .
.5 .FT.
. S .FT-
.5 .FT.
.5 - .FT.
S .FT-"-
S . .FT.
.5 .F ' TT '
. S F. T
1980 ____--- -S- -F- ------ -T- - - - - -
s F . T -373, 000
P.S . T-397,000 .
re . . T-423,000 .
r *
F. S T
F. S T
F . S T
F . S
F . S T
1990 ___------F---
F .
F -
F .
r S . T
F : ts : T
F : : %
5 T
?ooo I------F---------S-- T
..urce: Table 5 page 54 Task 3 report.
-------
t4 lS30-2CGu u
i\i;C '..'cod Fuel use and ',1,IC Emissions
Best Estimate Projection of Residential Wood Usage in Portland
£ ^ v~ I n ' ' r I- r, " i" .' ' r ~*
i or i j
-------
TABLE 02
Index Values for Certified and Non-Certified
Wood Stove/Furnace Use at Different Strategy Effectiveness Rates
Column:
10
11
rear
1973
4
5
6
7
8
9
1980
1
2
3
1984
5
b
7
8
9
1990
1
2
3
4
1995
6
7
8
9
2000
Wood Usage*
(Cords/Year)
New Annua
-0-
-0-
-0-
21,875
40,625
28,125
21,875
18,750
31,250
28,125
21,875
-0-
9,375
-0-
-0-
-0-
-0-
-0-
9.375
9,375
9,375
12,500
18,750
9,750
9.000
12,500
9,375
-0-
1 Cumulativ
18,750
18,750
18,750
40,625
81,250
109,375
131,250
150,000
181,250
209,375
231,250
231.250
240,625
240,625
240,625
240,625
240,625
240,625
250.000
259,375
268,750
281.250
300.000
309,750
318,750
331 ,250
340,625
340.625
Stove/Furnarp RWf Tndpy Valupc
Baseline Total
; New Annua
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
-0-
6.2
-0-
-0-
-0-
-0-
-0-
6.2
6.2
6.2
8.4
12.5
6.5
£.0
8.4
6.2
-0-
Cumulativi
12.5
12.5
12.5
27.1
54.2
73.0
87.6
100.0
120.8
139.6
154.2
154.2
160.4
160.4
160.4
160.4
160.4
160.4
166.7
172.9
179.1
187.5
200.0
206.5
212. S
220.9
227.1
227.1
1001 Strategy Effectiveness
Non-Certified
! New
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
10 yr old
-
-
-
-
-
-
-
-
-
-
12.5
12.5
11.25
24.7
49.3
63.2
71.5
76.9
90.0
99.8
104.4
93.96
84.6
76.1
68.5
61.6
55.4
49.9
- Certified
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
1.25
8.6
11.1
16.0
22.3
29.5
37.2
52.4
68.6
85.2
103.0
124.0
138.1
151.0
165.6
77.3
82.3
601 Strategy Effectiveness
Non-Ce
New
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
5.8
-0-
2.5
-0-
-0-
-0-
-0-
-0-
2.5
2.5
2.5
3.4
5.0
2.6
2.4
3.4
2.5
rMfipd
10 yr old
-
-
-
-
-
-
-
-
-
-
12.5
12.0
11.5
25.4
51.0
66.7
77.3
85.2
100.9
113.7
121.5
120.0
112.8
108.5
102.0
95.9
90.1
84.7
Certified
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
0.5
4.9
6.4
9.5
13.5
18.1
23.2
33.0
45.5
56.5
68.7
83.0
93.4
103.1
113.9
123.0
128.1
D-ll
-------
Column:
12
13
14
TABLE D2 (Cont.)
15 16
17
18
19
20
Year
1973
4
5
6
7
8
9
1980
1
2
3
1984
5
6
7
8
9
1990
1
2
3
4
1995
6
7
8
9
2000
Stove/Furnace RWC Index Values
901 Strategy Effectiveness
Non-Certified
New
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
. 1.46
-0-
0.62
-0-
-0-
-0-
-0-
-0-
0.62
0.62
0.62
0.84
1.25
0.65
0.60
0.84
0.62
10 yr old
-
-
-
-
-
-
-
-
-
-
12.5
11.4
10.4
24.1
49.0
63.4
72.3
78.3
92.1
102.6
108.0
99.8
90.8
83.3
75.6
69.0
62.8
57.2
- Certified
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
1.0
7.5
9.7
14.1
19.8
26.3
33.3
47.8
62.6
77.9
94.5
114.0
127.4
139.6
153.4
164.7
169.8
20S Strategy Effectiveness
Non-Certified
New
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
11.7
-0-
5.0
-0-
-0-
-0-
-0-
-0-
5.0
5.0
S.O
6.7
10.0
5.2
4.8
6.7
5.0
10 yr ol
-
-
-
-
-
-
-
-
-
-
12.5
12.25
12.1
26.5
53.1
70.8
84.0
94.8
113.7
130.2
142.2
151. 1
148.1
150.1
147.1
144.2
141.3
138.5
Certified
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
0.25
1.7
2.2
3.3
4.7
6.4
8.3
11.8
15.6
19.7
24.4
29.9
34.2
38.3
42.9
47.0
49.8
40J Strategy Effectiveness
Non-Certified
New
-0-
-0-
-0-
14.6
27.1
18.8
14.6
12.5
20.8
18.8
14.6
8.8
-0-
3.7
-0-
-0-
-0-
-0-
-0-
3.7
3.7
3.7
5.0
7.5
3.9
3.6
5.0
3.7
10 yr old
-
-
-
-
-
-
-
-
-
-
12.5
12.0
11.5
25.6
51.7
68.4
80.3
89.6
106.8
121.3
131.1
134.7
129.3
127.8
122.7
117.8
113.1
108.6
Certified
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
0.5
3.4
4.4
6.5
9.2
12.4
16.0
22.8
30.1
37.8
46.6
56.8
64.5
71.8
79.9
86.9
91.2
D-12
-------
exauiple (Table L)2), in 1992 wood usa^e was 2c6,375
or 1.729 tir.ies as ...uch as in 193C. This translates to a
1992 wood usage index value of 172.S relative to 1980 wood usage. The
increase of 9,375 cords/year in 1992 over the previous year is 0.0625
times as much wood usage as in 198C, for an index value of 6.25 (Column
4) representing nev; annual wood usage. This increase in wood usage
represented by the index value of 5.25 also can be assumed to
represent an increase in the relative number of stoves/furnaces,
assuming constant average wood use per stove/furnace. For a strategy
with 60% "coverage" - i.e., 60% of the purchasers of new stoves buy
cleaner (certified) units - the number of new certified units purchased
that year can be represented by an index value of 3.72 (.6 x 6.2);
and the number of new non-certified units (Column 9) by 2.5 (.4 x 6.2).
To calculate index values representing the number of certified
and non-certified stoves/furnaces in use in any given year, for any
strategy effectiveness assumed, the following three expressions were
used (the expressions shown are for the 60% coverage case, i.e.,
Columns 9-11).
To calculate index value for new non-certified stoves/furnaces
for year y (Column 9):
(Column 9)y = (1.0 - SC Frac)(Column 4 value) ,
(SC = strategy coverage)
To calculate index value for non-certified stoves/furnaces
1C years old for year y (Column 10):
(Column 10)y = (Col 10)^ - (Col lO^.j (.1)(SC Frac)
+ (Col 4)6.10
To calculate index value for certified stoves/furnaces for year
y (Column 11):
.(Column 11 )y = (Col H)y_i + (Col 4)y (SC Frac) "
+ (Col 10) (.D(SC Frac)
Where:
SC Frac = the fraction of new/replacement stoves purchased which
are certified - i.e., which emit at 5 g/kg or less.
D-13
-------
Column 11 -index values represent the number of certifiec stoves/fur-
naces in use. Column 5 index values represent the totcil sluveb/'fur-
naces in use. Thus, Column 11 /Column 5 is the fraction of all stoves/
furnaces in use which are certified. This certification fraction
(Cert. Frac.) can be used to calculate the RWC emissions reductions
fo" any given year due to the use of certified stoves, as follows:
I, ;,issions Reduction (%) = Cert. Frac. (0.75)(100)
..here 0.75 represents the assumption that certified stoves/furnaces
Bi,;it 7£/: la^s particulate then existing units. That is, certified
units 7.-, 11 average 5 c/kg vs existing emissions levels of approximately
27
2u g/ ' rvj ;;su ii.,dtec. by
Table u2 contains index values developed for strategy approaches
with coverage levels of 100%, 60%, 90%, 20%, and 40%. The last four
represent the four strategy approaches listed at the beginning of this
subsection. Table D3 summarizes the potential stove/furnace
particulate emissions reductions for all five cases, assuming
strategies are implemented in 1984. Since stoves/furnaces are
assumed to account for about 70% of total RWC emissions by the
mid-19801 s, multiplying the values in Table D3 by 0.7 affords
the potential reduction in overall RWC emissions (Table 7).
Table D3 indicates that the most effective of the four strat-
egy approaches, (testing/certification as a prerequisite for sale,
plus a 33% tax credit, which was assumed to be 90% effective) reduces
RWC particulate emissions from stoves/furnaces by only 3.5% after two
years (by 1985}. However, its benefits accumulate such that it reduces
these emissions by almost 16% by 1990 and by 56% by the year 2000.
The second most effective of the four strategy approaches ana-
lyzed, testing/certification as a prerequisite for sale, assumed to
be 60% effective, resulted in almost 11% less emissions by 1990 and
42% less by the year 2000.
The strategy approach assumed to be 40% effective, testing/cer-
*
tification as a basis for mandatory labelling, plus a 33% tax credit,
resulted in almost 8* less Ri.'C emissions by 1990. and 30% less by the
year 2000.
The least (20%) effective of the four strategies achieved a 4*
reduction in RWC emissions by 1990, and 17.5% by 2000.
D-14
-------
TABLE D3
Par 11 c j] u tc i_i:."i ss'i oris ileuuct ,cf' .', . .-.c.. i :\iC\
at
Five Strategy Coverage Levels
YEA;:
i^
1SC5
7
O
9
199C
1
2
3
4
1995
6
7
o
9
2CCC
Strategy Coverage Levels (% Clean Stoves Installed
of Total New Stoves Installed-)
IGui
i .
4.0
17.4
45.5
60.2
:c-
o . 3
2.3
10.B
31.1
42.3
^;/-
J . j
3.5
15.6
42.6
56.1
"
o.l
C.3
3.2
11.3
.
16.4
':/
i..:
7.5
21.3
30.1
Emissions Reduction (%} = (Cert. rrac.}(.75)(100)
Example Calculation (1985; 90% Coverage):
Iii.issiuiis Reduction ,':0) - \Ccrt. Frac.) (.75; {lu(J)
Ei.iisbion Reduction ',:-} 7 .49/1 JL. . - \.75;\1JJ' - 3.:>
D-15
-------
for Selecting. 33% lax Credit
In Portlana, Oregon participate emissions from UV.'C are now pro-
jected to exceed total industrial particulate emissions (tons/year)
oy the mid-19COs. Pollution control tax credits are available in
Oregon to industries which must install particulate control devices,
32
for UH to 50% of the installation costs. Tax credit levels for wood
jiirriin<_ equipment can be estimated using industrial ^articulate control
CuS'.S .
A recent study addressed growth management issues for the Port-
land airshed. It estimated industry must pay about $10,000 in pol-
lution control costs per ton of particulate to obtain emissions off-
set to locate in tiie Portland urban area ($5.00 per Ib. of TSP). Up
to 50', of such costs would be eligible for tax credit under Oregon
32
laws and regulations. The Oregon Department of Environmental Quality
estiii.ates that average TSP emission factors are 40 Ib/ton (20 g/kg) for
stoves and 20 Ib/ton (10 g/kg) for fireplaces.
A household which burns 2 cords/year in a wood stove (2 X 1.75
tons/cord =3.5 tons/year) would emit 140 Ibs of TSP per year (40 x
3.5 = 140). If these emissions were to be counterbalanced by industrial
emission reductions, it would cost either industry or the state through
its tax credit program a combined total of $700. If a residential
tax credit proyrau were set up in a manner comparable to how the
industry program operates in Oregon, then the state could subsidize
up to $350 of costs if these emissions were totally controlled, or
about $253.00 if the emissions were reduced by 75% ($700 x .75 x
.5 = $262.50). This significant level of economic incentive to purchase
cleaner units could stiuulate development of cleaner units even if
their manufacturing costs were several hundred dollars, more per unit
than "dirtier units".
Another approach to setting a tax credit level might be to assume
that development of such cleaner stove/furnace designs would add to
the costs of producing a unit by, say 50%. Then.whatever the price
of the unit turned out to be, an appropriate level of tax credit to
D-16
-------
offset development costs, would be 33% (50% cost increase is equivalent
to 33% of final total costs). Thirty-three percent of the assumed 1984
competitive cost ($1200) of advanced design stoves/furnaces is $1200 x
.33 = $400. This value was selected for purposes of this analysis.
Modifications of Installed 3toves/Furnaces
a< Air Inlet ,-ioaifications
tlarnett reported research findings 1 on the effect on emis-
sions of a simple change in air flow pattern. A thin-walled con-
vection wood stove v/as tested. Instead of introducing air as
normal from both a front and back draft hole, the front hole was
slocked off, and a tube was extended from the back draft hole hor-
izontally to the back center. Air supply was thus introduced be-
tween the logs near the center of the stove. Particulate emis-
sions were found to decrease about 50% as a result of this simple
modification. This finding suggests that manufacturers of stoves
might be able to reduce emissions by 50% with inexpensive modifica-
tions to the air supply inlet construction, perhaps for $20 per
stove or less in additional construction costs.
Since optimum design is not known for certain, in order
for manufacturers to ascertain whether the addition (of an air
supply tube into the back center of the firebox) actually reduces
emissions, some simple emission measurement technique is needed
that could give manufacturers inexpensive feedback on emissions.
Without such feedback widespread introduction of this or similar
Modifications may not occur at all.
As a retrofit strategy it is unreasonable to believe that
more than 1 or 2% of stove owners would ever be sufficiently concerned
about air emissions to^ voluntarily make such a modification. Retrofits
would be more likely if significant fuel savings resulted. A
strategy of requiring that stove owners modify their existing
stoves by changing the air supply configuration does not appear
to be practical because no single "modification kit" could apply
D-17
-------
to c.11 stoves ana there coulu JG serious safety problsus if novice
stove owners were to alter tr.eir stove designs. Thus no emission
reduction credit can be claimed for this "retrofit" strategy.
b. Insertion of Firebrick in Stovebox
Souc have theorized thot possible flai-.e quenching ^..r
firebox ,,'alls coulc! o-j reLuceo by lining ciie stove box with refrac-
tory ur firebrick.
Firebrick insertion into the stove box has been theorized
oy sci.ifc as a ;;:eans to increasing co.. '.bust ion zone temperature anc
co!,.busticn efficiency anc! thereby reduce emissions. Insufficient
combustion zone ternperature can mean less than coir.plete combustion,
because the spontaneous ignition temperature of volatilized wood
^ases ranges from 670 to 1200° F.13
However, research on this technique as applied to a thin-
waned stove by Barnett n did not show any significant emission
reduction. Accordingly, no emission reduction can be expected
from this practice.
c. Heat Transfer Improvements (Fans)
The application of fans or blowers to existing units for the
purpose of heat recovery from stack gases can theoretically increase
thermal efficiency, thereby reducing the amount of wood burned.
Assuming combustion efficiency remains constant, if heat transfer
efficiency increases, then gross efficiency increases by the same
proportion. For example, if modifications to exisitng stoves could
increase heat transfer and increase efficiency from 50 to 55%,
(assuming combustion efficiency remained constant)^9% less wood
(55-50)/55 would need to be burned to produce the same amount of
heat and theoretically 9% less emissions would be produced.
Research by Shelton on one fireplace-stove showed that
application of a larger blower with rouyhly 570% more cfm (900
vs 134) than the existing blower increased energy efficiency by
D-18
-------
margins not exceeding 5%. This suggests that increasing blower
capacity on a unit designed to have forced air for heat transfer
is not likely to reduce emissions by much more than about 5%.
15
Barnett , in work comparing the conditions of 1) no
forced-air heat exchanging and 2) application of a blower, founa
about a 5% increase in thermal (heat transfer) efficiency resulting
from adding the blower.
For the homeowner who might be convinced to add some fan
behind or near their wood stove to increase heat transfer, the
thermal efficiency improvement (and theoretical emission reduc-
tion based on reduced wood burning) is likely limited to less than 5%.
Even if 20% of homeowners were to install a fan near their
stove or increase the blov;er capacity on stoves with blowers, if
the improvement in thermal and overall efficiency is limited to
5% as discussed, then only a \% reduction in wood burning might
occur. Thus the practical potential for this strategy as a retro-
fit strategy is considered to be negligible, or 0-1%.
d. Add-on Particulate Control Devices
Re9arding particulate emission reduction achievable for
stoves by add-on devices only two sets of tests have been done.
The first was by the Oregon Department of Environmental Quality
on
and the second was part of Task 5 of this study. In the 1980
tests sponsored by DEQ, a steel wool mesh filter (cost $150)
inserted into the stack was found to reduce total particulate
emissions by 60% (limited two test comparison).
In work by OI-iNI and Del Green Associates in 1981 under Task
5 of this contract, the emission factor in a test with the steel
wool mesh filter was actually higher (limited two test comparison).
D-19
-------
Ir. unuc.i-:-r ^et uf J,;,,I/Jel dreen tests one add-on cocal^i.c
afterburner v/ds tested. It also was inserted into the stack about
six inches above the stove Lox. The test with the add-on unit
showed1 slightly lower emissions, by about 10%, but this dif-
ferential should je considered negligible in light of experimental
error.
Jiven other uncertainties a^out how lon^ these adc-on con-
trol devices ;',;ight ptrfori;., anu whether clogging i.iay ultimately
occur, it is uncertain that any significant add-on particulate
control device will be available in the marketplace in the
next five years, where significant device is defined as a
unit that can reduce emissions on a continued basis by 20%
yet still cost less than $150.
In order to withstand public opposition to government re-
quirements for a retrofit device that reduced emissions from wood
stoves, any such device would have to have proven significant effec-
tiveness, maintain effectiveness over time, overcome all potential
safety problems, yet still be reasonably inexpeensive (i.e., less
than $200). Because of the lack of data indicating such devices
to be currently available, the emission reduction potential from
such a strategy is considered to be negligible (0-1%) for the near
future.
3 Improved Design of Add-on Devices for Fireplaces
a. Underfire Air
The effect of underfire air on fireplace emissions has
been tested to a limited degree by PEDCo-Environmental (January
1979). Of 18 source tests conducted for fireplaces, one of the
tests measured emissions from a fireplace with underfire air.
This test can be compared to four other tests with similar burn
rates and same wood type, as shown in Table D4 below. This com-
*
parison indicates about a 40% emission reduction was achieved by
application of underfire air to a fireplace.
D-20
-------
TABLE D4
PEDCo Fireplace Source Tests: Underfire Air
and
Electrostatic Precipitator Comparison
Burning
Unl t
Fireplace
Fireplace
Fireplace
Fireplace
Fireplace
Wood Type
Dry Pine
Dry Pine
Dry Pine
Dry Pine
Dry Pine
Burn Rate
(kg/Hour)
11.4
8.2
11.5
10.1
15.2
TSP Emission
Factor (g/kg).
9.5
16.6
15.3
16.7
8.7
Control
Measure
Underfire air
None
None
None
Electrostatic
Precipitator
Although this one particular test with underfire air showed
a 40% (41.4%)emission reduction, the burn rates in these tests
are perhaps twice as high as normal burn rates. Thus, this same
percentage reduction might not be achievable at lower burn rates.
The underfire air unit tested cost about $SO. This low
cost for the sizable emission reduction that was achieved in at
least this one case, argues that more research is warranted on
this low cost retrofit measure, especially over the range of burn
rates comiTionly used by individuals. Given uncertainties about
whether these results apply at lower burn rates, the technical
potential for emission reductions by this technique is estimated
at 0 to 40% for an individual unit, based on this limited test
information .
This strategy would have to be applicable as a retrofit
strategy in order to have significant effect. However, there is
a far greater chance that a retrofit device such as this could
be developed and conirnercialized for fireplaces than for stoves
since one or two designs likely could fit most fireplaces. Po-
tential safety problems such as air outlet hole plugging would
need to be overcome.
D-21
-------
i he retrofit cevicc would necessarily include a -le/.'er
system which would require use of electric power. Even if
ti.e units were given free to dwellings with fireplaces, probably
only about 50% of households ,,ould utilize the units. Practical
emission reduction potential would thus appear to be in the 20,,'.
rc.ncc ^ )v- firt-plaC'j units to v;iiich this technology >s applied.
- c..i,"i SS i OCi3 c.!"i'-. i,iiuS tliat '» o I ut ,S LiSiJ T^T 'Ci'lS Ci,iCU~
Jc '- s 111 .actiu tc ^u ."^'JuCv_'-. ^^ i_'j/' ^y ^iL.t>u .imcn O'^UCLCC ^u ^
ion in all i\',;C c-i,.i ssiuns of 2, ~.y HjOO i.K 1( ._ - .'-2) tut o'
naif that amount by 15CO.
b.. Electrostatic Precipitator
It has been hypothesized by some that an electrostatic
precipitator could control emissions despite incomplete combustion.
Although feasible, the high cost (about $1400) for the emission
reduction achievable (perhaps 50%) r.iake this strategy unlikely
as a widespread solution for individual fireplaces (and also stoves
by extension).
In one of the P.EDCo tests cited above (Table D4) & 45£
(46.3%)eirrission reduction was found to occur when a commercially
available ESP was applieo. The "Smog-Hog" used by PEDCc in their
tests was reported to cost S350 in 1977, and is estimated to cost
SHOO installed in 1932.
Even assuming optimistically that such a 45% reduction
could be achieved for all burn rates, applications, etc. this very
hiyh cost ;r,akes this strategy impractical for individual units.
For apartment ouildin^s where multiple flues nay be tied together
to have a cor.won exhaust flow, economies of scale ;;iay be able to
ri-uuce costs ^er Fi >~e-,jl aci1 to ..irjre rt,.-asonajl-j -jvels.
D-22
-------
o 1 c: 3 3 J C G T S
Can t.ie sppl ict.t iui. of ^lass doors alter the combustion
process in a fireplace s'jcn that greater coiiibustioti efficiency
aiic lesser emissions result? .Although the available data aga",n
1£
'.s lii:iiteci , it appears that 1) operating a fireplace '..'ith jlass
-c.urs iiiut uro..at icall., r.-.-ci-ces ^ross efficiencies ^urin:, the bLr-;,-
.j ,.'-.»'.^c juJ^Li^e t'.t. -'-j r..v-jce iioet transfer, C.K 1,' ^':\-<.r-.r,-_
: _ f-, r _,;"; ^. ,/~\\': ,_ . . . '-. ^Ic'^E, Jocrs _,r Ooi,:' _.:v.,,.i '..( 1 ,
during the night time burndown/smoulder phase can cut house heat
loss by an undetermined percentage. Regarding combustion efficiency
and emissions, no evidence was found in the literature that glass
doors as normally installed can either increase combustion efficiency
or reduce emissions.
L-. ."ieouCinCj .sooci usage
This section reviev.'S tne following strategy approaches for
reducing R'/iC emissions by rc-Gucinc, ,vood usage:
1. keauciric, home heatincj requirements
a. .('etherization
j. Reducing stove charge size and burn rate
L. L.-^rov 1 fi'^ n'ood fuel CjucnLy
a. Select "ion of ,,-&od ritii higher heetinc, '-i^\\-:
j. ,.oisture ccntenl: control (seasoning)
1. Fireplaces - i.oisture content effects
Z, otovcs/furnacos - i.iO'isture content rf.jctf
"o. Direct restrictions on wood use
a. L,ji secle controls
D. Ci'i.ission oensit^ zo:>in'.;
D-23
-------
_c.fw'f- . :,_^ss:;..^ ';!..- i L," : t _ _,y api-iroochc-s in this Scct.^i, j
general LI scussion is prcscracu of the relationship betv.een burn rate
and particulate emission, because it is relevant to several of the
strategies evaluated 'hereafter.
Effects - Stoves/Furnaces
J i..i"i i S> 1 GITS iTJi. StO V£ S ,' T U f'l luCS S >'_;'
are a function of the amount of wood burned (Ibs/hr, kg/day, etc.) and
the emission factor of the woodburning unit, usually expressed as grams
of particulate emitted per kilogram of wood burned (g/kg). This idea
is illustrated schematically in Figure D2(a). Both of these determinants
of RWC emissions - wood usage and emission factor can be a function of the
rate at which the wood is burned in the stove/furnace (kg/hr).
A given ai.iount of wood burned should provide the same amount
of heat whether it is burned slowly or at a more rapid rate, provided
that the combustion and thermal efficiencies of the burning unit remain
constant. This will often not Le the case, especially over a wide ran^e
of burning rates, for several reasons. Hotter fires (higher burn
rates) may lose more heat via exhaust gases, reducing thermal effici-
ency. Slower burn rates may not maintain sufficient temperature in
the firebox for as complete combustion of volatiles, reducing combus-
tion efficiency (and increasing emissions). The stove operator also
i;iay believe that at lower burn rates his heat output is not adequate
and add more wood.
For purposes of this analysis wood usage is assumed to be a
direct function of burn rate (Figure D2(b)). However, the emission
factor is assumed to vary with burn rate as shown in Figure D2(c),
based on research described below. This relationship is important in
estimating the potential emissions reductions achievable by several of
the strategy approaches examined here.
D-24
-------
FI'CUE U2
Jerieral relationships Assumed
Setv/een
Key ,»ooc burning Unit Variables
RWC
Emissions
Rate
(g/day)
EF = x
where:
EF= Emission
factor (g/kg)
-, r~ ' . - y, ^ ' -. . ,1
i *: , ^ \ fj C I ^ ! u U I *J> ^ C /
cr.ii ss ions 'is the
product of .VOGC:
usage and c...issiun
factor.
'.'.OOC
Usage
(Kg/day)
>urn Rate
wood Usage varies
directly with burn
rate (combustion
and thermal effici-
encies ,repair: constant
hours of burning remain
constant).
Emission
factor
(g/kg)
C. Emission factordecreases
as burn rate increases.
Burn Rate
(Kg/hr)
D-25
-------
I'licvc/Turticcc- emissions ^s: results r _",".:..._ 'J j-lj. cl-ji-rl^ sno..
that as burn rate increases, emissions factors decrease. This reflects
niijher combustion efficiencies at higher firebox temperatures. How-
ever, whether or not total emissions over tiire is greater or less at
Ltie hi'jher burn rates depends upon whether the higher wood usage at
higher burn rates offsets the lower emissions factor. That is, if
doubling the burn rate cuts the emission factor in half, but twice as
,,L.ch .;GGu is uurned, the total emissions per ^.uj v/ill ue the sa^ie.
,-,'e have assumed for purposes of this analysis that wood usage
.-,11 vary linearly with burn rate (Figure 02(bj). However, the
variation of emissions factor with burn rate is apparently not linear
'.,-i^L.re .jl\c;, F^ure D3j. The latter, non-linear relc'o ior,sl-.i,, ;.;ust be
examinee! more closely, because it has important implications for
several T;.;C strategy approaches, and for such practices as operating
stoves/furnaces in an "airtight" or banked mode.
Review of Existing Research
Sutcher (1979) published findings that particulate emission
factors from airtight wood stoves are inversely proportional to burn
IP
rates and directly proportional to fuel load in the stove box. He
derived the following equation to describe this relationship:
lactor = 10-73
where, i;, = initial fuel load in firebox (kg)
q = combustion rate (10,000 Btu/hr)
uther researchers >J> also have noted how emission
factor increase dramatically as burn rate decreases. While this may
seeir, to suggest that stoves/furnaces should be encouraged to operate at
higher rates, the situation is not necessarily so simple, because the
higher wood usage at higher burn rates could be an offsetting factor.
The quantitative relationship between emission factors and burn
rates is not understood completely at this time. In work conducted
D-26
-------
"in till s study ^Tdsk'j;, v,hea.St_c or,
Figure 1)3 illustrates these cwo different rtpresental ions of
the relationship between burn rate and emission factor, i.e., the Butcher
and Del Green Associates equations, respectively. The uata plotted
in Figure D3 are shown in Table 05. This data was derived using the
burn rates in Column 1 in both equations 1 and 2 above to calculate
an emission factor. To assure consistent treatment of the different
burn rate terms in equations 1 and 2, a conversion factor of 4258 Ctu/
Ib of wood burned was used. For Butcher's equation, a fuel load of
-j.2 KC, ,-,as assumed (o = 6.?), hecniis*3 this oroduced e^issic^s dr.? «»''_
si on rates of similar magnitude to those from the Del Green equation.
A different "m" value could be chosen and the relative change in
einission factor for a given burn rate change wculc bo about the. same.
Tlie "i.," value of c.2 ;,as chosen for this example because then the
t'.vo ei,.ission factor curves in Figure 03 are in close proxii.iity and it
is easier to perceive their similarity of slope.
Figure D3 shows that the two equations are similar in curve
shape, and similar in position on the graph when Butcher's rn = 13.
Table D5 shows that for a burning rate decrease of 0.5 Ib/hr, over
a range of burning rates (Column 1), the two equations afford different .
changes in relative emission factors (Columns 2 and 3). Butcher's equa-
tion indicates that the increase in emission factor for a 0.5 Ib/hr de-
crease in burning rate will be greater for lower initial burn rates
(Coluh.n 2i. The Del Green Associates equation indicates that each
0.5 lb/r
-------
300
Figure D3: Two different representations of the
relationship between burn rate and '
emission factor.
Y = 10.73 * m/q + 1.18 (Butcher)
Y = 156 e
(Del Green)
1 2 3 4 5 6 78 9 10 11 12 13 14 15 16 17 18
BURN RATE (LB/HR)
C-28
-------
TABLE D5
Emission Factors Calculated for a Range of Burn Rates
Using the Butcher and Del Green Equations
Burn Rate
Ob/hr)
0.5
1.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
8.0
10.0
14.0
16.0
Emission Factor (g/kc
Butcher
10.73(m/q) + 1.18*
297
149
75
60
50
44
38
34
31
28
26
20
16
12
10
) Using Two Equations
Del Green
156/e'84x
129
107
73
60
50
41
34
28
23
19
16
7
3.5
.75
.35
* "m"
m" assumed to equal 6.2 kg,
D-29
-------
" ., . _cr 1^;^ i. :~ inures ^4 arid Jo iho..' the
t° -.jcrcob-- ,ii c.i i j -> ;ur, TC.CC tur i uiucn ,^'iuer c.r_
cnan;,es, using the Jutcner and Del Green Associates equations, respec-
t i vely .
In TaDle 06 the relative amount of wood burned ^ Column 4) is
.w'.^ruCiJ ~j tiiC .j^r, i"dt.c. liiitc.ier s c^ud
..ill be the io.,-_ i ;, all
t,., issioi! rates (assu.iiing operators continue to chc-rce the sari.e
uf ..otjc ,.£r locdin.j). Tiie Del 3reen Associates ec^c'.tvj- ..i^icc'.--^
^ , _. , ._o v. r. i _i. . i s s ; u n s P^r o oy ' /uu i c JL ^ r o c u(jr or i ^. ^ b - ^ r--J ^ ^-' ^' { * ' ^ ^ \' '- ' ' u
.,,...'_.! _uri; rat-.^, ,. i zli r&LiUC-ici tutol -2:.:i ss ions h^'" ;^ -'i-; -'-'-f 'j'll^
f.^i' _>..r,; rule uicroases below uLout L.J 1^/nr .Cc-l-^..,. .,. 'ou,.
C/7 shows how the total wood burned, heat output, arid ^articulate emis-
sions woulo vary with burning rate for a ten-hour burn period, v;here
emissions are calculated using both the Butcher and Del Green equa-
tions. Total wood usage (Column 2} over ten-hour ranges from 15 to
^ Ibs, governed by burn rate (Column 1).
Heat output (Btu) similarly ranges from 6.4 to 23.6 10 3tu/hr
\Colunm 3). This range should cover the space heatiny output required
for most homes, since Day reports that typical wood stove burn rates
24
produce about 8-15,000 Btu/hr.
Columns 4 and 5 indicate how total (10 hr.) part icul ate emissions
vary for each of the burn rates in Column 1, usinc both the Butcher and
Del Green equations. Total emissions are essentially the same in all
cases (Column 4) using Butcher's equation. Using the Del Green equa-
tion, total emissions peak at a burn rate of about 2.5 Ib/hr (Column
5). This is probably a typical burn rate for households in climates
comparable to Portland and Seattle. Barnett's field studies in upstate
New York for climate with about 5000 heating degree days per year
(comparable to Portland and Seattle) found stove burn rates most
commonly in the 2.0 to 2.5 Ib/hr range. p Columns 6 and 7 show how
dramatically emissions per unit of heat output increase as burn rate
decreases.
D-30
-------
o
I
CO
o*» in
*
o tn
4> to
tn tn
cn OD
co ro
tn co
VO O
ro ro
00 '
O 4*
ro i
' tn
.p. vo
, __,
tn '
10 ^
_j
-j *sj
** ^
^j r*
>>i cn
4* ro
CM
,
ro o
< i
i i
o
| ^j
tn 4* 4^ co co ro
O tn o cn o tn
ro ro
oo ' tn ' ^j 4i
o 4^> to 4^» **j cn
ro ' >
tn ' ^j 4^ ro
4S. 10 45. *sl CM .
i i i
tn i 4^ ro o
IO 4* ^-J CM ' I
t
i i
i 4^ ro o
4^ "~J CM 1 ^J
i i i
-«j 4^ ro o co
~-j cn > i -**i ro
i i i i
4^ ro o < co 4=.
cn i ^ ro 4^
i i i i i
ro o ' co 4^ tn
i i -^j ro 4^ co
i i i i i i
o co 4^ tn cn
i ~o ro 4^ co '
i i i i i i
> co 4* tn cn cn
«vj ro 4^ co > oo
i i i i i i
co 4^> tn CM CM j
ro 4^ co co 4=»
ro
0
ro
'
i
o
i
i
_^
^i
i
CO
ro
(
.£»
4=.
1
tn
CO
i
cn
i
CM
CO
1
V^J
*"
1
*^J
00
J
tn
i
O
1
1
1
1
CO
ro
i
pv
^
(
tn
CO
i
CM
T'~l
1
CM
co
i
*vj
^
i
^4
co
t
CO
ro
» H
CD 2.
c r-1- /
-» u /
3 o, /
°> /
r+ /
fD /
/ _
' / CT
cr / -^
37 "*
/
/
-
tn
ro
o
ro
tn
CO
o
CO
*
tn
j.,
O
^
f
tn
tn
o
tn
tn
CM
o
/
31
01
CD
j
3
70
o>
n>
c
I,"1
fl)
o
o
->
n
o
(..:
d
o
_ I-.
fv ;,
rv
c^
f )
c^
O
-------
^-^Final
Initial
Burn Rate
1.
2.
2.
3.
3.
4.
4.
5.
5.
6.
Burn Rate
Ib/hr
Ib7ht^-^
5
0
5
0
5
0
5
0
5
0
1.5
-0-
33
65
98
130
161
193
224
255
286
2.0
-25
-0-
25
49
73
97
121
144
168
191
2.5
-40
-20
-0-
20
39
58
77
96
115
134
3.0
-49
-33
-16
-0-
16
32
48
64
80
95
3.5
-56
-42
-28
-14
-0-
14
28
41
55
68
4.0
-52
-49
-37
-24
-12
-0-
12
24
36
48
4.5
-66
-55
-44
-33
-22
-11
-0-
11
21
32
5.0
f~ O
-02
-59
-49
-39
-29
-19
-10
-Cl-
lO
19
5.5
-72
-63
-53
-44
-35
-26
-18
- 9
-0-
9
6.0
-74
-66
-57
-49
-41
-32
-24
-16
8
-0-
D-32
-------
TABLE D6
Emissions Per Day Resulting From Changes in Emission Factors
Caused By Changes in Burn Rate
Calculated Using Butcher and Del Green
Burn Rate
Change
(Ibs/hr)
1.5 to 2.0
2.0 to 2.5
2.5 to 3.0
3.0 to 3.5
3.5 to 4.0
4.0 to 4.5
4.5 to 5.0
5.0 to 5.5
5.5 to 6.0
Ratio of Emission Factors
@ Lower Burn Rate (g/kg)
L« Higher Burn Rate (g/kg)
Butcher
1.3280
1.2451
1.1953
1.1622
t
1.1384
1.1207
1.1068
1.0958
1.0867
Del Green
1.210
1.210
1.210
1.210
1.210
1.210
1.210
1.210
1.210
Ratio of Daily Wood Burned
@ Lower Burn Rate (Ibs/day)
@ Higher Burn Rate (Ibs/day)
Butcher or Del Green
0.75
0.80
0.833
0.857
0.875
0.889
0.900
0.909
0.916
Ratio of Total Emissions per Day
@ Lower Burn Rate (kg/day)
@ Higher Burn Rate (kg/day)
Butcher
.996
.996
.996
.996
.996
.996
.996
.996
.996
Del Green
.908
.968
1.008
1.037
1.059
1.076
1.089
1.100
1.108
Assumes: 4285 Btu/lb of wood burned,
D-33
-------
TABLE D7
Total Wood Burned, Heat, and Emissions Output
During a Ten-Hour Burn at Different Burn Rates
Burn
Rate
(Ibs/hr)
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Wood Burned
(Ibs)
15
20
25
30
35
40
45
50
55
Heat Output1
104 Btu/hr
0.643
0.857
1.071
1.286
1.500
1.714
1.928
2.143
2.357
Particulate Emissions
Kq/10 hours
Butcher
.678
.681
.684
.686
.653
.692
.694
.697
.700
Del Green
.599
.660
.682
.677
.459
.616
.573
.526
.479
Emissions/Unit of Heat
Kq/104 Btu
Butcher
1.055
.795
.638
.534
.459
.404
.360
.325
.297
Del Green
.933
.771
.637
.527
.435
.360
.297
.246
.203
1
Assumes 4285 Btu/lb of wood burned.
D-34
-------
fi , ' ,.-. 1 ., i-J^--,~-+--iU-iv-r
u ^ r . i ; , ^ i \3i~ij _ u r >!_, ii.iuiui ouc^t-i Oi ci r i r c
An additional relevant characteristic of stove particulate emis-
sions is that aoout b"L-« of the total ei.iissions are prcduceo in trie
first one-sixth \~\77.} of the burn. This finding was first made by
^t^Ciujr , i". rJ77J cnii coiifirmed by 0.u.E..'<. test in... conductec in l^L.i
.,, V.;", .'J ".".is r,hencne...a can be best understood
_ ,..,'...-.._ ..: . ^ f!r, n., . ,",c;; CCCLF. Jurin^ *;c
,,rcLcSS&s .niCn occur are:
. .jter is vaporized
/L/iotiles are vaporized/co.nbustec
J,ur.nr; the '.nitial stages of a fire, tlie relatively cool fireb'ox
temperatures (heating the stove's thermal mass takes time) and the
presence of steam can retard complete combustion. Since the greatest
a,, tuut of vclatiles are produced in the initial stages of a fire, a
relatively ^reater oxygen supply is needed to enable close to complete
combustion to occur. This explains the basis for the coi.n.ionly cited
recommendation of "burning briskly in the first 20 to 30 minutes" of a
new fire or after a large charge of wood is added to the firebox.
Although there is no direct estimate in the literature of the
reduction in emissions which is achievable by "burning briskly in the
first half fiour", such an estimate can be generated based on the burn
rai,e discussion presented above. For example, for an individual stove,
if the operator "burns briskly" at three times the normal burn rate
during the first half iiour of a four hour burn, he will be reducing the
emissions rate expected in the first one-eighth (30/240 minutes) of the
firing period by 33%. This practice can be estimated to reduce emis-
sions by about 25%, provided the total amount of wood burned remains
constant, as shown below:
D-35
-------
^f 3,..;ss'ions occur ,n first v.< ;,.ir,i:tcs
~ ^ . X C i * Ci i_-rw( .lif!. u^'i/
k burning occurs for 75% of that time
(30/40 minutes)
brisk burning is assumed to be three times
t!ie normal burn rate, which implies a 67%
a,, ission rate reduction durinj that ti;,,e
,/er'io , and a 20C% increase in amount of
..c.cc burned during ti.ese 30 >,. mutes
Emissions are thus assumed to be reduced by 25% for the
entire period, assuming the total amount of wood burned
is the same. .50 x .75 x >67 = _25
" ,.:3 fcr 3!, individual stove, it is c:ti.£t;u i:,r>t . rnv.,
'<_ -~ ,.!_ I'M-, s the normal rate during t,ic r"-,rsi OI-.L-^ i;,,- i;, ^r t,-;e
fire coulo reduce emissions by about 25%, so lent, as the wood ournea
per fire does not change, however, tripling, burn rate during the first
one-ei^nth of the nornial burn length would result in a 25% increase in
overall wood usage, unless the burn rate during the remaining seven-
eighths of the normal burn length is reduced to 75% of normal. Two
cases are considered in Table Do in which the burn rate during the
remaining 7/C of the fire: 1) is at the "normal" rate so that overall
wood use increases 25%, and; 2) is reduced to 75% of normal.
In Case #1 the temporary decrease in emission rate achieved oy
ourning briskly during the first 3C minutes, is offset by the fact
that maintaining the normal burn rate during the rest of the fire
increases overall wood use by 25^. The net result is no decrease in
emission coaipared to the Base Case.
In Case #2, after burning briskly as in Case #1, the wood use
(burn rate) during the rest of the fire is kept below "normal" such
that the total amount of wood burned over the course of the fire is the
same as the Case Case. The net result in 17.9% less emissions compared
to the Base Case.
Assuming most households would not cut normal wood use back by a
full 25% during the final 7/8 of the fire, a more realistic assumption
could average the results of Cases #1 and #2 for purposes of this analy-
sis, it .vas assumed ,.iost probable that relative emissions (last column
above; .vould be reduced by about 10%. It was further assumed that no
D-36
-------
75
C'
-5
(D
-S
CJ
r*-
-S
ID
l/i
I'D
-5
CM
O
0
ro
-s
o
o
c.
re
r.
ft/
PJ
a> fD
-- n.
l/l
t/1
OT
o
o
-h
fD
0
GO
^1
n.
^~
-5
T^i
t>
-n
_-.
CO
r-t-
y.)
CL
O-
C
-s
1.
^3
t^;
r>
!.
-5
£
U)
O
C
C1
O
c
-5
o
c
2.
35
to
-h
-5
00
0
re
to
o>
o
~n
ro
O
c
rt-
f
X
(^
-s
t/1
to
o
3
3
fD
o
c
r .3
Co
X
t;i
>
r;
fj
c.i
cr
ri-
c.
X
X
r-t-
o
Z!
r:
rr
ra
t/i
-s
to
r .
r:
-------
vi >_ t,i.ui", i. ^r .,, v iGuotj."C iL.s COL. i L. bij jjt.rs Jade'., ic c.'.Uo JUP; brisuiy
;n~ rocucL r,ur..ul V.UUL. use c.Lr,;u c,i^ rjsc ^f ;iie T , rx. Tins rcsullj
in i.iost (jrojaLle einissicns reductions of 3.5* froi.. burnind briskly only
in the fire ,/ith moderate wood use thereafter.
".ix.lucc. - ^urti /.ate Iffects
.i-j c.iji.^e ',.,11 occur .vnen fireplace jurini;^ reies are elttrtc. T'.;i
-------
jj ^ji'li: t'..s cc-;.., c,.s fo ~ -.'^rr. rc-.es arcur.d r.5 IL/hour, but tl,at
i .prcvtci vr£.i_uCc'v / cuCcl ei :'i ss ions can occur at io\/er jui n rate's, t.rc
worse thigher; total e;,,'.ssions ar, occur at higher burn rates (Table
Do, Column J).
Tii.rd, bc.std ur; the evidence at hand v-ye cannot de-tens.me '..!ie!:;-ci^
i'..:. _.uLcr-:i'" t r _-el .:f-_--... _>L/c.L:oi, "is ..ore appro,, ri ate. for jse :'er
!
. r,(_r..uS'j^. !u..ever, .ju ncls 'elicit buth ec,udt"ions afiorc t;.e jci...t ^r
3r'Krox i,..ucelj the sa:,,e results In the "i.iost co;,i;,'iOn" rancje of burr; rates
,L-J) K;5/'r,r; Tabl;D5, C'jlL,i..,is 3 ar,d G, entries 2- o n. C- r°. p o ^ u I' i ; u 'J o :. '.. ' ; :. J J : -
."cr.^c :.r ;^.";. r^-^eo - ....,
-------
ruuiai-a heat stored in the refractor,;' material after the fire insioe
has dieo down, and; 2) Richard Hill's refractory lined, water-cooled,
turbulent air furnace, which uses water as well as refractory material
for heat storage and circulation.
Fifth, we have so far used Butcher's equation by assuming
constant fuel loads UJ. This is consistent with typical operator
urcceuures. For exah.pl e, She 1 ton has noted that "many, If not ;.:ost,
operators use about the sauie size fuel load under c.11 conditions and
use the cor.ioustion air control to regulate power output". ^ However,
r's equation v. ith q held constant also implies that euissions"
rat':S cLi. 02 recuced by charging sraaller loads of ./ooc , s.neller ;,, in
Butcher's equation) while maintaining e constant burn rate, or rate of
heat output (q, Btu/hr). This provides a basis for postulating emis-
sions reductions from inducing operators to charge smaller loads of
wood while maintaining their normal hourly burn rate (q), i.e., to
charge the stove more frequently with smaller loads (m), while burning
the same amount of wood over time.
This would be less convenient. It is perhaps most palatable and
likely to occur for smaller stove sizes where the "normal" load for a
larger stove would overfill the smaller stove's firebox. This is
relevant to the strategy approach of down-sizing stoves to allow
"hotter fires" without making a room uncomfortably warm. A "hotter
fire" should increase combustion efficiency, lowering emissions.
However, if the fire is made hotter by increasing burn rate, increased
wood use can cancel any benefits of lowered emission rates, according
to Butcher's equation; and for the Del Green equation for the "most
common" burn rates.
Alternatively by charging smaller loads (m), more frequently but
maintaining the small hourly burn rate (q), emissions should decrease
in proportion to decreases in average charge size (m). Especially in a
smaller stove, this could result in higher firebox temperatures (better
combustion efficiency; lower emission rates) for several reasons.
First, there is less stove mass to heat, so the same wood usage should
D-40
-------
be able to keep it hotter. Second, smaller charges may ,,.ean less
uiiourned wood m the stove at any tii:ie. Unburnecl wood can act as a
heat sink, lowering firebox temperatures.
1. r'.Gclucinc 1-iGi.iG ileatino iieciui regents - '..eatherizat ion
3',iice ,r,any Households have convartec to wooa neat inc. as a
.,leans to cut space heating costs, weatherization proqrar.is have been
corisicoreu o.y sone air pollution agencies as a i::eans to reouce wooc'
ourr.inr er.c thereby particulate emissions. If a household is
v.eatherizec to cut heating costs and that household as a result
does not convert to wood heating then particulate emissions are
indeed less than they otherwise would have been.
However, for the household which already is heating with
wood, weatherization may not necessarily reduce emissions for two
reasons, even though house heating requirements are reduced.
First, the household may continue to burn as much wood as before
weatherization and simply reduce reliance on conventional fuels
such as oil, gas, or electricity. Secondly, an operator may begin
to operate his wood stove at a reduced burn rate to avoid over-
heating his newly weatherized living space. This decreased burning
rate results in a significant increase in particulate emission
rates, which offsets the lower wood usage, resulting in no net
decrease in emissions. However, emissions may be reduced by
burning on fewer days. Because the weatherized house retains heat
better, there may be no need for RWC on marginally cold or cool
days. Emissions may also be reduced on burn days if the wood charge
size is reduced.
In order to know for certain what happens to annual total
emissions from an individual stove when a household is weatherized,
ideally a set of experiments should be conducted .as part of which
stove operating time and conditions are monitored both before and
after a dwelling's heating requirements have been significantly
D-41
-------
reduced. Unfortunately, no such experiments have been conducted to
these authors' knowledge. In lieu of such information, two scenarios
were chosen to give a range of possible emissions reductions from
weatherization.
CASE
In the first scenario, it is assumed that annual wood burning will
be reduced by about 33% for those households weatherizing (woodstove
households only). This reduced wood use will occur by burning 15% fewer
days (on marginally cool days when space heating is no longer needed),
and by burning 21% less wood per day on those days the stove is used.
It is also assumed that most people (67%) will achieve the 21% less wood
by further reducing the air supply to the stove and therefore reducing
the burn rate, but will keep the wood charge size the same. For those
households, the reduced wood burning rate (kg wood/hour) will result in
a higher emission factor (g particulate/kg wood burned) according to
Butcher's equation:
emission factor ( 9 participate } = k m (kg wood charged)
kg wood burned q (kg wood hour)
Since the total emissions equals the emission factor times the amount of
wood burned, for these 67% of households the decreased amount of wood
burned is offset by the increased emission factor resulting in the same
total emissions on burn days as before weatherization (higher emission
factor x less wood burned = same emissions).
It was further assumed that through an education program, the remaining
33% of the weatherized households could be persuaded to reduce the size of
wood charge at the same time they reduce the burn rate, resulting in the
same emission factor (g particulate/kg wood). The total emissions will
therefore be reduced by the same percentage as the reduced wood burned
(same emission factor x less wood burned = less emissions/burn day).
For those households using woodstoves and weatherizing, then, emissions
will be reduced because of 15% fewer burn days and because some households
(33%) will have reduced emissions on burn days. The emission reductions
D-42
-------
will be:
Fewer burn days: 15% days/yr X (100X emissions reduction/day) =
15% reduction of emissions/year
Lower emissions on burn days: 85% days/yr X 33% households X 21%
emissions reduction/day = 5.9% reduction of emissions/yr
Total emissions reduction/year: 15% + 5.9% = 20.9%
It was also assumed that 60% of all households need weatherization,
and 80% of those needing it will be weatherized, resulting in 48% of all
households being weatherized (60% X 80% = 48%). If 70% of all woodburning
households use wood stoves, then the total annual emissions reduction
averaged over all woodburning households will be: 20.9% emissions reduction/
year (weatherizated wood stove households) X 48% households weatherized X
70% wood stove households = 7.0% annual emission reduction for all RWC
households.
CASE #2
For this scenario, some slightly different assumptions were used.
As in Case #1, it was assumed that 48% of the households would be weatherized
and that 70% of'the RWC households have wood stoves. However, for this case.
it was assumed that wood use will be reduced 40% on burn days, and there
will still be 15% of marginally cool days where no burning will occur. It
was also assumed that all weatherized households will either burn on burn
days in the same manner but fewer hours as before weatherization (same burn
rate and charge size), or will reduce the wood charge size the same amount
they reduce the burn rate (but burn the same number of hours as before
weatherization). In either case, the emission factor (g particulate/kg wood)
will remain the same after weatherization and the total emissions will drop
the same amount as the drop in amount of wood burned (same emission factor
X less wood burned = less emissions). The emission reductions from weatherized
wood stove households would be:
Fewer burn days: 15% days/year X 100% emission reduction/day =
15% emission reduction/year
Lower emissions on burn days: 85% days/year X 40% emission reduction/
day = 34% emission reduction/year
Total emissions reduction/year: 34% + 15% = 49%
D-43
-------
Averaged among all RWC households (weatherized and unweathen'zed,
fireplaces and stoves), the emission reduction will be
49% emission reduction/year X 48% of homes weatherized X 70% wood
stove households = 16.5% emission reduction for all RWC households.
The assumptions used for these two cases are included in Table D9.
TABLE D9
Comparison of Assumptions and Resulting
Emission Reductions for Two Scenarios
Regarding the Effect of Weatherization
Common Assumptions For Both Cases:
50 million BTU/year heating required before weatherization:
30 million BTU/year furnished from wood fuel
20 million BTU/year furnished from conventional fuel
60% of all households need to be weatherized
80% of households needing it will be weatherized
Households will heat on 15% fewer days after weatherization
(no heat on marginally cool days).
70% of RWC households have woodstoves
Weatherization will have a negligible effect on fireplace use
since fireplaces have only a marginal heating function.
Case #1 Assumptions:
Annual use of wood and conventional fuels will drop 10 million BTU's/
year each (33% less wood, 50% less conventional fuel, 40% overall)
67% of households will reduce burn rate (kg wood/hour) but maintain
the same wood charge size (kg/wood) after weatherization
33% will reduce burn rate and reduce wood charge size after
weatherization
Current oversized stoves will not be replaced by smaller stoves
by the year 2000
Case #2 Assumptions:
Daily sue of wood and conventional fuels will drop 40% after weatherization
100% will either reduce charge size and burn rate, or^ will maintain
the same charge size and burn rate (but burn fewer hours) after
weatherization
Current oversized stoves will be replaced by smaller stoves during
the normal replacement cycle
D-44
-------
Annual Participate Emission Reductions Averaged Over All RWC Households:
Emission Reduction Emissions Reduction Total Emissio
From No Burn Days From Burn Days Reduction
Case #1
Case #2
5.0%
5.0%
2.0%
11.4%
7.0%
16.4%
a. Weatherization of All Households
Thus the total potential emission reduction for airtight stoves
which is estimated to result from weatherization (reduced emissions on
burn days, reduced number of burn days) ranges from 10% to 23%. For an.
area where stoves contribute 70% of all wood burning emissions (e.g.,
fireplaces contribute 30%), total wood burning emissions would be reduced
by 7% to 16% from such a program under these assumptions. Assuming that
of the homes to be weatherized, 50% would be weatherized by 1990 and
100% by 1995, then the emission reduction benefits would be 3.5% to 8%
by 1990 and 7% to 16% by 1995.
o. '..eatheri nation of Only households Instul line, i.ew Stove/Furnace
If this strategy ,,src to oe ,;-.od-.fied so that v;eathenzatior.
..o'uld only be required of households installing a new stove,
sc..ie ^reater circumvention likely would occur. If the circumven-
tion level is arbitrarily assumed to be 3U'i, the 1995 and 20CU
c;.,:si,ion recuct'ion benefits ,mld be about Z.b;! £.nc 5/t,
respecti vely.
2. Improving ;.oocl Fuel Quality
a. Selection of i.ood Fuel with Higher Heating Value
Information "is available on how energy content varies by
wood species, but little is available on how emission rates vary
by wood species. The energy or utu content of different species
D-45
-------
o,.o. w>Gu_,ii.s T , r, >.i'.i' ;xs~ G-J; j.ion ly USLC ,.oi/c ty,>c "in tiit , £L , i ;_
Northwest, contains 21 million Btu's per air dried cord (7673 But's
per pound) while pine contains 16 million and oak contains 31 million
38
Btu's per air-dried cord . Values for 8 species are shown in Table D10.
Despite the fact that Douglas fir has 18% less Btu's
per pound as Oak, there is no testing information on how particu-
late emission rates vary by wood species where the same stoves
and conditions were used. Lacking information that emission rates
are comparable per pound for different species, no emission credit
can be claimed at this time from the use of wood with higher heat
content.
Even if Oak wood did produce 18% less emissions per pound
or kilogram as Douglas fir, supply constraints likely would limit
the switching from Douglas fir to Oak to less than 10% of house-
holds currently burning Douglas fir which would yield a negligible
emission reduction of less than 1.8% (18% x .10).
b. Moisture Content Control (Seasoning)
The traditional assumption is that burning dry wood can sig-
nificantly reduce particulate emissions and creosote formation,
presumably because lower moisture content wood requires less energy
to valorize i^cristure which should result in higher combustion zone
temperatures, uore con.pletc combustion, and therefore, less emis-
sions. The interrelationship between wooc! moisture content and
particulate emissions is not understood .completely, but some
research has been conducted \.hich provides insight. The research-
D-46
-------
TABLE D10
, i, i ., , '. i" ,. 0 C C r L. iJ i i; 0 o '
Species
Cedar
Douglas Fir
Madronc
Oak
Pine
White Fir
Alder
Maple
Drying
Time
6 - 8 MO.
6 - 8 MO.
6- 8 MO.
6- 8 MO.
6 - 8 MO.
6-8 MO.
18-24 MO.
6-8 MO.
Heating Value
Million Btu per
Air- Dried Cord
20
medium-low
21
medium
30
high
31
high
16
medium-low
17
medium-low
21
medium
~ t
26 .
high-medium
.'Jregon iiooc Heot Handbook'
D-47
-------
tj.it ant ^articulate cv. .ssions incluuc .udlin-., eno /'.hlintj11,
1 " ')' "^ C
Larriett , Del Green Associates u, Auuurr, University"'"', and
i;.c. fol 1 o,,i!,_, ~ , L^UOO , ..in, ~i (->! r.cis UMU jLuvcs/'f urru.CLi
i. !_ r- ur d i, L 1 _, ,. i L . i , C(- r, > c.c . ^ v. *i i j vi r/_-"' i" . r s t.
1. ir i ;'-,-<] uCcS - . ,t.i s -Lire _ov.M^ii;it £ffacts
V 3 i
1 '- T , L
. i' .-ijurf: .", . :ji,cltor: v,"ic not
i'~'- . - ! . J^ j^i" . _ , , ^ _, C.., j .. >. -. "i L , , . L r - L J , (., i ',;,' cl T , C ': t.1 C_.' .
.. . i.'Ji: CO,.nJ'J3 t i 01. -_'t"i ". C i LiiC_) iS t.!i i i iu I C L.t i OI'c Gt COii p 1 C1 tentiS S Of
Cw,,,L'uSt ion, ,;e :cvc i-3su,..oo for ^ur^osei of this ar,al>sis tliat the
fraction [1 - Cci.ibustion efficiency] is a relative indicator of ^ar-
ticulate emissions.
According to F-,c,ure Jo, coi.iuusticn efficiency decreases
fairly steadily (i.e., emission's increase/ as moisture content
increases. For example, in this one set of tests, unburned combus-
tion products constitute 22.-y.o (1-.775; of the total chei.iical
cr,erby in the unburned wood at 2b\ rr.oisture content but only about
L'j.i of 1L> wood n.oisture content. This iiiiplies that emissions
r.i.J-it be reduced Dy about 11" for fireplaces for a ,;ood moisture
content shift froi.'i 2^ to lu', , .o.sture content, . .vici; is equivalent
to a l.G% drop in emissions for each 1/t drop ir, wood moisture
content. However, while this relationship is the best available
information, its applicability at wood moisture contents above 25/i
can DC- assumed but is not proven yet.
iioteworthy is the "flattening out" of She!tor,'s curve between
lo and 25% Moisture content, which suggests ^'replace emission
rates may be less sensitive to wood i.ioisture content changes at
0-48
-------
VL UO
W ! i I . ,"
Ui;
u...Jus Li on Efficiency
100
e
>-
UJ
Ul
UJ
MEAT TTV^SFER EFFICIENCY
OVERALL
EFFICIENCY
I I
I 1 I
0246 8 10 12 14 16 18 20 22 24 26
MOISTURE CONTENT f'/O
The dependence of efficiencies on moisture content in an open
fir-vlace stove. Here power output could not be held constant but
increased with decreasing moisture content. Fuel loads were of
uniform size and were added when the previous load had been reduced
to charcoal.
Source: She!ton
Ik
D-49
-------
.._- (j , Ct i i_ _/> J -.'.. > -. . _, . . _ J - j .( . j - i L>_ uJ t " . c .or LI I..-JS L, .
uivon t.vis fiin-", r.j, We isl'. mjLc- tiiut for ;/ooc bstv.'een 25 c;i;d j~
nioisture content, anu burner i,n fireplaces, each !'< reduction in
,.ooc ...ci sluru cGi,t..r:t is asscc aleo ,/it,i a 0 to l.J/. Deduct i or,
. Ti '.,,!, i _i s i cri r c1 ct. s . ,,/.'. , _ c L, rv _ , t c. ^ LC; i . i !_ " .. -ti. ,'ecii -^i.1 0.1 : >-
content.
L...I', ti.- :csti,i, _, /...I,, .:i,j ;",'MI;P. c,lsc inuicete
" ^
H
r or i 1 'i c,/ i aCvi ur 3 C 3 ,.01 - .. ^. _ . i >Li.'i^ I i ~ ! -i / , C.'i" tr rOc CcS t S >< . t f ;
1 ,\i moisture content , uo,. ,iu>_ ivorj^e stack aas CO concentrations
j T j i 0 p p i H i r a n ? e 1 i « t L ^ ^ -, / , . ! , ; i c t . i j one; test > .' i t n 4 I > . i o i s u u r &
content ,vcod had stack cas CG levels of 3200 pprv,, or about a 10-
fold increase. For this case, the effect of Moisture content on
emissions was greater than ,,;ould be surr.iisec fron, Shelton's curve
as depicted in Figure L-o.
Even if the relations/rip for fireplace wood burning between
.noisture content aric particulete emissions were known for certain,
one riajor other "unknown" ,iust be estimated in order to derive
an estimate of how much parti cul ate emissions could be reduced
by racist ure content recucticns. This factor is the percentage
reduction in average wood moisture content that could be achieved
by various strategies such as public education, i.'hen several
different estimation Methods are used, it appears that a 2% reduc-
tion in average wood ..icisture content is a reasonable estimate
of what could be achieved by public education programs. These
different estimation r.iethods are discussed below.
Estimate 3ased on Hypothetical Distribution by Moisture Content
For the hypothetical analysis below, we assume that the dis-
tribution of ,-iOOd by i;:oisture content 'JM.C.) roughly can be approxi
D-50
-------
..uuo stoves \Hurtlunc, Lre^onj I'uS clc.ii.ied tiiat it is uncoi^on
for wood stored in tr.e Pacific :!orthv/est to have a n.oisture cci.tent
Delov; 25'.. If soi,,e;"ivj, c.11 -,'coc burned i.ere tc ut driec lender
and protected more efficiently, such that all wood was to hav<= a
I "; 1 3 ujj^iufi >-u jc -" ,uOL LijJ^Cr iCVc. I iS'tli^fitt.
, ^,.i.»'cf"j .iw t/r ^'", . .; i .'- =i"fcCtlV£ "ili dcili^ "i I'l-^ liiltViC1
' ^ , . ,. , . },<:. _,'\.;.i ," , 'C JiiVcn : cMtx . . ..
^,ur.:^-_ L;, j,. ....- .^.olc ...rlov,, hy^cthet'icc:! esci,,,ot
O of i.o,/ ,.uc; ..^'^ ,,,^; s ...re content would be reduced for
e ,,.c. cauo^ur . jb of L'^., 30., end 35%.
i',oisture content 2i;« reduce 10% = 2/: ^0% reduce 5% = 2%* Ko reduction
reduction \,ithin 2J';i reduce o;- = 1.2% 20% reduce 2% = .4% assuniec
category assumed ZG% reduce 2% = .4% 40£ reduce 0% = 0°^ achievable.
3.6% 2.4%
* T!.e 10% and o« reductions cssu:,,eLi for 35% r;,.c. '.vood are constrained to
:ji. fur oO'^ 1,1.c. wooc since it is c-ssui'iec reductions below 25% are unlikely
^cxsec on toe aLove table, if one-tin re of the wood is in each
of the three r.i.c. categories, then for all wood these changes
equate to e Z/' reduction in average wooc! moisture content {.ZZ
X 3.6%) t (.33 X 2.4%) + (.33 X 0%) = 2.0%. This value is 40%
of the maximum potential reduction identified, which appears rea-
sonable.
Survey Based Estimate
Data is not available on typical wood storage practices for
trie Pacific Northwest as a dhole, but was collected for Portland,
rt O
2-3JLtle, and Spokane in Task 21 {Surveys)4' ir this study and for
D-51
-------
Uj^.:^i~_ J^^!"L:_ ,.. ,^,t . o -i ;.S S:l;V, r .,, ,,, ] _ Dll .. j 1C .
i str i ju L i Oi'i is Cuiisi(.<_rcu to be r,:ore rc-presoritut^ ve of i<:c
liortnwast, because it is a true areawide survey, v.'heroas
; 2:> survev v/as acre in i sincjle residential nei^
..",;; ._ i" ;^.C:, ^r,^;, _r ""a-'.rlj Similar.
TABLE D 11
>.coJ 3:orage Practices in ,',ecford, Oregon
IJj] State survey Findin.jS
oe nones ^.y;
e nr Shsc 17.^/'.
Ccverec uutside 51.5/,
Jticovered Outside 29.0%
Coi'ubi nation 1.8^
The storage category for w'hicti the greatest moisture content
rcaiiCtions COL,Id probaoly be achieved is /,/ood whicii is stored un-
covered outside, ,-,'e assumed that 50% of this 29% of households
could be "educated" to alter their wood storage practices (i.e.,
10 outc-oor covered storage) and that this would reduce wood inois-
tura content frd;: e. oST- average to a 2SC/, average (scniev;hat ,,iore
than the 25« f.,.c. assumed to be best attainable in the Pacific
Morthwest clii.iate). This would result in reducing average vjood
i..oisture content ai.iong all fireplace users by about 1.0% [(35-29)
X .5 X .2Sj and emissions by .0% (.8% eiiiissions drop per 1% ni.c.
ciiange x 1 .C% change).
Sor.ie Moisture content reductions also could be achieved by
the 51.5% w'ho store their wood "covered outside". Of the nouse-
holds winch reported they store their wood "covered outside", the
plastic or tarp partial covering method used by ,i:any also could
D-52
-------
jjrutecC'ivi an... r-MuC.. j\'crc.L_ .i.oisture by about 2','. Tir's ,;oul<-
result In reujciii;, average ,,'GGu i..oisture content Gi.,0!ig all fire-
place users by acor..t .5'. (I- x .33 x .515) and reduce emissions
'-Jj . -' - > . -'. .Ji.,~i b 1. ', G!1?< OTjp ,-'-''' ''- ...C. CM£I)_,£ X ,~~,',' CilaM'jC / .
I i , i - -.' r KJ u , I- I i _ u C G i' V i .~i C £_' C L 0 ^ .j C- S 0 .'1 u i 0 ^ r , u v. . '-.'' i
p;. i~, L i_ s , so..;;- ;'..u,iiuiil r^.-.-.c^iGii it; av^ra^c- ,,occ M-CiSLi.rL L^.L.
could L/e dCnieveo. The 3.3.1.'^. iiedford survey found that 3^.-.
iiolui ubLdi" :!.'^'.r .....jv. .n Septes.l/tr and October. T! '
of house:" c Id
U . ._i , L- , ,v.',l _ . _, ./r .. ... . . j ... . . _j _iiO w Jl. Li i, , i~ i i LI. L -. . k- I i . O_ -
I'JoS li.ui; 11 ,.!...-,ti.;, , ." :.r ,c c.,,j survey. For purposes of this
analysis, we assim.c L..C.I oVGut 17* of housenolds burn tneir woou
within 'f months or less of cutt'ing. If wood cutting policies were
altered oy forest r.ianayj,i,c'r.l acencias such as tfie USFS, Z.LI1, arc
state forestry departments to allow wood cutting only from March
through July, *,e estimate that the extra seasoning t'!r..p coulc
reduce the i.ioisture content of /,'ood from governnent lands by 5%
or less. If CC« of -.vood supplies are .derived froi.i government
land, these assumptions yield a reduction in wood moisture content
for all wood of 0.7% (5% x .17 x .8 = .68) from the practice of
restricting fall wood cutting on government lands, or an emission
reduction of C.3% (0.7% ,,..c. change X .0% emission rate reduction
per 1% i.i.c. decrease = C.5G/-J.
However, given this relatively sr.iall achievable reduction
for this strategy, it appears unlikely that these benefits are
large enough to persuade the forest r.ianagenient agencies to change
their practices. Forest management agencies prefer to have remove-
able wood residues resrioved as quickly as possible to allow faster
replanting. 5cr,,e of these agencies perceive this policy change
would delay returning forest lands to a reforestable state.
Dr53
-------
J . . J _ ' , 1 - - , , s. - 2 ' I ' I . V, I. U
c o '-' - r 111 ^ r o r ., o o u s L >_ r j u u j t. s i ^- c is i_. i \ . " . < - i! . 1 /
Tall outtirij on jGvertii.cnt la;.cs » ~ : L/ i - v- '- f" - ^ v- M 'sx C 1 :
i r.e most co.,iij1c"ce s^. cf uatu cr 1",^., vi ~, i^.or.s fro,n stcvc-s/
furnaces car, :jt ex^ecteo to vary '..'itii ...c'isturj content is acain
available froi.. ,-.'ork by Slieltor!.1" Shelton's findings for one air-
tight stove are shown in Figure 07 below. Only combustion effici-
ency v/us inedsured and not ;;articulate e;;.issions. However, lackincj
bettor data, for purposes of this analysis we assume that particu-
late emissions are proportional to the fraction [1-combustion effi-
ciency]. In this one set of tests, optimum !i,oisture content v/as
found to be between about 20 anc 30% (wet basis).
uecause the combustion efficiency curve is non-linear, si^-
i.ificant uncertainties fc,,,er3c v;i en trying to drav, conclusions about
riOw i.-.uch emissions could be reduced bj charuj'in.; wooc; i..01 sture con-
tent. For exarr.ple, in discussions with Sheltcn, altiiougr. the shape
of the combustion efficiency vs n.cisture content curve is tiiouj-ht
to be similar for different stoves, the band of optimum moisture
content range may be different for different stoves. This is sig-
nificant because, if the curve were snifted about b percentage
points to the right, a much lesser improvement in combustion effi-
ciency would result from chancing from 30% moisture content wood
to 25% moisture content wood. This is illustrated in Figure D3
D-54
-------
r- T ^ Mr, r- ~i *7
I" 1 U U I > rl IJ /
effect of i.ood Moisture Content
on
Stove/Furnace Combustion Efficiency
MOISTURE CONTENT (% - DRY WOOD BASIS)
0 10 20 30 40 50
COMBUSTION EFFICIENCY
MEAT TRANSFER
EFFICIENCY
0 10 2O
MOISTURE CONTENT (% -MOIST WOOD
The dependence of efficiencies on fuel moisture content in an
airtight stove. The air inlet setting was varied to maintain an
average power output of about 17,000 Btu per hour for all moisture
contents. The fuel load volume was approximately constant.
Source: Shelton
Ik
D-55
-------
-'cilu. . l..u curves iicvt JetY; a:,ded ':c Sneltor, 's cor,,L L ST. jr. _f
..r.Cj curve SiiG..ii >[i r i-jUre ^/ as ussr-ed-l i r.c c^rv^s. ; _s_- L.,^
curves art- assumed to have the same siiape but are shifteo c per-
centage points to the ri^ht ana left. The reader can note ho\,
the fraction [1-cci.. bastion efficiency] changes for a s;ecific
'.LI--. c:;.L^;'it level if different curves ere assu. ,tO.
'. s<--^^:,d i , ortuiit jncortaintj/ is the <_ istr : -i..L , .. . f . . "/
.vur;u_ ^j ..jist-vx coriCiiVc. For exaii.pl e, if ILL, of tin:- ',,ocu
irjrnec; hoc c 30; M.C. level the emission reduction acl. .evcjlc ,,OL!C
be much greater than if the average m.c. were 25%.
-LSrici oic£_ L/H-V.-I'LL: i ;iL i ^s , s;x different oSjLu'-.pt1. or^ ,;^rt -^\..
atec. ^..."iSSion rouuctions caseo on the fraction [1 -coir.biisc ion
efficiencj] ,;crc evaloaced for the tiiree different curves s.io1..;;
in FiCjUrc DC-. For each of these curves, two different VJCQC.-'
.Moisture content distributions were evaluated, as shown in Tabl
12.
TAoLE D 12
,.oou .',01 sture Content Distributions Evaluated
(Fraction of Households Assumed In A Category)
Assumed Average »ood _ , _
,-:oi sture Content Cese } Case
25% .333 .375
30% .333 .500
35% .333 .125
D-56
-------
FIGURE Do
Three Assumed Moisture Content
vs
Combustion Efficiency Curves for Stoves/Furnaces
50
MOIbTURE CONTEMT (% - DRY WOOD
10 20 30 MO
0 10 20
MOISTURE CONTENT (% -MOIST WOOD ftASIS) ,
The dependence of efficiencies on fuel moisture content in an
airtight stove. The air inlet setting was varied to maintain an
average power output of about 17,000 Btu per hour for all moisture
contents. The fuel load volume was approximately constant.
Source: Adapted from She!ton
Ik
D-57
-------
i" u r -_'.,. .. v- .i1.,.. s i x j c c n c. r i o £>, u 11 c c.c i 11_ v _: _ i
Effects of reducing r...c. belo;, 25« were necjectec since tins "is
considered difficult to achieve in the Pacific i!orthv,est.
,\'\ acdi t i ^L,'! factor , <..s considerec: i r, these e.^issiufi re^uc-
-,.,, ^rtluuli., ...:. -: cc.,, it Ji-Lri fro;, i .;3..^ct '.:.^ F'_,.,-. 7, ,.
i l_ J «, i \ j 1 I i i L. C* f r ., ( I ^ ,' ~ i ,"_ i . v i M i 1 0 <.* L L, r U ( i S I X,' i 'J.I ! ^ t tj i > C . t i ! 1'
i . _' 1 i j i' C i" ^ u . o i _* - u r\_~ C u n .^ CJ' i c r u 0 L* C i* 1 0 r i S !> ! 0 u i C- i i! C r' c u ^ x.-' / v:.'}" c. ' i
reduce e,:; i Sb'i uris .
ror users ,. ,L'~, ,/ooe in the 3(j anc 35« ,,i.c. category, it <;as
assumed tiiat the follov.uii., in.c. changes i,,it,-ht be achieved:
35% Category 3C% Category
20% woulo decrease ri.c. by 10% = 2% 40% wculd decrease m.c. by J'/.'*= 2.0%
201, w&ulu decrease ..i.e. by G% - 1.2% 20% would decrease ir,.c. by 2.\ - 0.4%
20% .vOLild decrease i.i.c. by 2% = .4% 40«. would decrease ra.c. by 0% =0.0%
40% i.ould decrease ,,..c. uy C/l = 0"-,
2.4%
* Constrained to 5/o since M.C. reductions below 2ul
are considered unlikely.
The true distribution of wood burned by moisture content
level is not known. If this distribution is 1/3 at 25% moisture,
1/3 at 30% moisture, and 1/3 at 35% moisture content, then
average wood moisture content would be reduced by about 2.0%
(.33 x (3.6% + 2.4%) = 2.0%). This is consistent with the
D-58
-------
i. . I , . GlSCurO COI'it-int rC"J'_iC i. i Of. v S Su.nr," . i >'- -n-v.. j_ -'
a.juve. If tne en stri but i or, is Better c^ru,:;; .^c,j.. :^ c ^7.^','j^ ,
1L.5% split for »,ooc in the 25',c/30%/35% ii.oisti.re content level
then average wood moisture content would be reduced by 1.65%
[\.125 x "3.6) -i- (.5 x 2.4) = l.C5%] by the oLove assuiuptions.
Fill t^.jlc 'ijt-lu,. S"i>.-.-S ''<-''-: cStl.t cIC _ 'f.. -> ij rC-^.OCt "i OTiS
i C(. 1...~ -- - fv/r of.-it ^ x './. r r^''-' ' .;L. i.,'.o." i . s , L.'jiiij ti;£
;r^cec,ure LseO- to Estiinate Stove £i,,iss"ior; ile'Juciiwii PoLerit'icl fro!,:
.eci.ci.-ij '..ooc i!oi sture Cjnte.-it
in.- r r tV_ c i on i_ 1 -eo.'i.J Ji i- i ui . I "
proportional to ^..'C particulate einissions.
Calculations were ;!rade for six different cases:
Three different curves were assumed for i.ioi sture
content vs combustion efficiency, as shown in Figure
DC. Une was the same as the combustion efficiency
curve in Figure D7. The other two were assumed to
be either_5% points to the right or left of the com-
bustion efficiency curve in Figure D7.
Wood moisture content distribution was assumed to be repre-
sented by 1 of the 2 cases below:
33% of wood is in each of the three ui.c. categories
25%/3G%/35%.
12.5% assumed in 35% u,.c. class
50% assuii.ed in 30% u.c. class
37.5% assumed in 25% ni.c. class
For wood in the 35% i.i.c. category it was assumed:
20% will drop to 25% i.i.c.
20% will drop to 29% fii.c.
20% will crop to 33% .TI.C.
40% will remain at 35% m.c.
D-59
-------
" U("
.not 2C/. jecai.se
-- ..il "0|j CO I_^A . ,~iOt i'../, JECol.Sc '"' ..CuC C'i.i'f
ally stays above 2Zi i;.c.)
20/ ,; i 11 arop :o 25% ^not 24% because- Fi.i, >,vood gener
ally stays above 25% i-i.c.)
TABLE D13
1. luVcS,
- o ,v ' r " iv- - ' I- w' '"-' I 0 I.U I C U I i L, I . r- r ^ rx/J i i»- »- -I ^
,oti(..rio ut«iv_ i.. ji_t 25%/30?'/35% -miss ion i\eouctioti
Resulting
1 c .3337.3337.333 5.5;:
2 C .3757.5007.125 3.5%
4 B .3757.5007.125 a.1%
5 A .3337.3337.333 11.7%
5 A .3757.5007.125 9.9%
AVERAGE
The average reduction in [UiC particulate emissions froi.i all
six scenarios is 0.2%. This applies to stove/furnace emissions.
In the previous section an average 1.7% reduction in RJC particu-
late emissions from fireplaces was estimated for a similar reduc-
tion in firewood moisture content. From Task 3, for an area like
Portland, Oregon, 1933 K'.'C emissions were estimated to be about
70% attributable to stoves/furnaces and 30% attributable to fire-
places. Thus, the overall reduction in total RWC particulate emis-
sions, attributable to the wood moisture content reductions assui.ieo
Mere is estimated to oe o.2% [.7(£.2%J + .3(1.7%)].
-------
, y^u ij .iL/Lit.llj d", str "i iyjte:i ai.,GM';., the three .,:c~isture content cate-
Oor,t.s of 2;5"/i [...c., 3U:/ .M.C., and 35% rn.c. - i.e., Case 3 previous-
-, >i . -p -i r 1O - o'"*c'/O^'"'/''"1'^'''
i . ^,c:SCr '1 J JU ": f! i u J i S u Ic ab ^O/j/ ^O/"/ O^ /^ .
,"..., r" , L. r J ----> w i t- 1. L« u t" * t I Ly j_t~CCi"iULS'-i^;. - ' 'J . « \ ^ . L.
. ,; .. - r .- L " , " L11 _ ".". r c c . .0 i s "L u r o c l r i z _. . , _ , - ,
.,_,,: , Lo ui'.j :.> 0 juft i CL 1 cte J!":-i ssi uns fr^.., jur,,i,.^ . iji L,
these moisture content values. The values obtained for the quantity
Combustion Efficiency Moisture Content Percentage of RWC
TSP Emissions
16.2% 35% 40.9%
12.6% 30% '31.8%
10.8% 25% 27.3%
The values in coluir.n two were used to calculate the relative amount
of total fll.'C particulate emissions which are attributable to wood
in tacri ,i,.c. category. This ~.s shown above in column three.
For 'ihe ,,ood in the 35% category,
For the 20% which drops to 25% in.c., [l-coi.'ib. efficiency]
shifts froi,i lb.2% to 10.8%
For the 20% which drops to 29% m.c., [1-coi.ib. efficiency]
shifts fro,',; lu.2% to 12.2%
For the 20% which drops to 33% n;.c., [1-coinb. efficiency]
shifts fro;n 16.2% to 14.8"%
For the 40% v;hich remains at 35% m.c., [1-coiab. efficiency]
regains at 16.2%
D-61
-------
'' j- r ~ -f- f ' ' r I <^ ^ t * ""f ~^
, _ ^ . i ». i Ii j ui iti:>c , i.1 c v.,U cil i I ! LJ' [. I ~^om>jU 5i L i Ufi i i f I C I 3!lCy j '- L'~
^ r c, a 1> d o t r u i 11 I u . il /'j t- 0 I *T v *; /o \. i1 I C M Q Cj U a t cj S u 0 ~i I J . S- ~, P c u U C c i 0 fi .
hu'.vever, while the change in the combustion efficiency vs m.c.
,s not linear, heat transfer efficiency changes in a linear fashion.
iach 1% i,i.e. decrease yields a 1.5% improvement in heat transfer
/:^"! 2 L--\lu',." ! .2(0''-,
to a 4.V,'/- htat '.I'u-ij: L-I' arf iCicnCj ui^ruve-
-e 07;.
THUS reducing v.ood with 35% moisture content bj e.\\ average
.,r _.v M: n.c.st'jre content reduces '-'..'C c:. issioiis in tv/o .
-------
. ..T - .^7... l;ncc j^/". ,.i.c. './cod or icjii'iol ly Accounted for 31..-,
o.c total !U;C particulate emissions, this reduction in its emissions
represents a 3.3% decrease in total \l\tC particulate emissions.
For -..'God in the 25% ;.;.c. category,
.0 C:'ur,_.e is :
-------
. ; VL. '. _-sts cGii'J'jcLc.^ j- Cu. VL i'3'.'le conditions or an {. ini_.';t ,.uCv,'
i^m, for four tests with wood at 16% moisture content. The CC
emission rates was 1500 ppn. for the other run at 41% i,,oisture con-
tent, ,«hich suggests an emission factor increase of 150% comparing
the Lurn, IT_, cf lo/, vs si/ .iicicti.rc.- content ,vood in an airtight stove
^iclton'j fi.ic, .r.j for '. ,,^.J c.t 1^^ ui;;i 35C.< ,,,cisture content
.jxlrapolatec fro.,. ^-'. to '.!.", ti,-j combustion efficiencies fur 1 j%
j>;d 41'; i:;.c. ,/ooc arc -Jl'i. vs 7.., cno the percentages of unjurnee.
j,.issious SnOolc. be aDOut 7o' .,.,_,i!jr (22-13)/13 for the 41,,' ,...c.
,,uoo coi.iparec to lu/, ,,,.c. ,,'Guvi. This is within t factor of tv.'O
cf the value i!5u%/ derived cirectly fro>ri the Rudling/AMing date
for carbon ii.onoxide emissions.
^arnett also has published limited stove test data which
provide insiyht on the effect of moisture content on particulate
emissions. Of 51 tests conducted, the second and third highest
emission factors wer-i recorded for wood burning in airtight stoves
with 3% and 24% i.ioisture content wood as compared to the other
49 tests with wood in the 30 to 40% moisture content range. The
findings that emissions were higher for 3% moisture content wood
is consistent with Shelton's findings, but the observation of near
,, axin.uii! emission rates of 24 > moisture content is not.
Lastly, moisture content research was conducted as part of
(") r*
Task 5 u of this study. Nine different tests were conducted.
A total of six test runs were conducted on an airtight stop stove
for the specific purpose of determining the effect .of fuel moisture
content on emissions. Two tests were conduced at each of three
different moisture levels -- "dry, medium, and high" moisture wood.
Figure D9 presents the emission results from the six tests as a
function of fuel moisture.
D-64
-------
FIGURE D9
70
Particulate Emissions As A Function
of
Fuel Moisture
60
50
en
to
c
o
to
QJ
-t->
ro
3
O
40
30
20-
g/kg, average
a g/104 Btu
g/10^ Btu, average
10-
(Wet)
(Dry)
10
11
20 30 40
25 43 67
Fuel Moisture, %
50
100
60
150
D-65
-------
The results of these tests indicate the optimum fuel moisture
to be in the 25-35 percent range (wet basis), which compares quite
well to the work conducted by She!ton, except that the optimum fuel
moisture is shifted upward to 30% from 25%. Again, an increase
in emissions is indicated when fuel-moisture is either increased
or decreased significantly. Although these data indicate there
is some uncertainty regarding the optimum fuel moisture level, it
does corroborate that as moisture changes, a change in emissions
will result.
In order to determine how emissions versus moisture content
would compare between She! ton's test and Task 5 results, a single
analysis similar to the analysis done on Shelton's data was con-
ducted using the correlation derived in Task 5. The Case 3
scenario was used except that the beginning wood moisture contents
were assumed to be 35, 40, and 45% instaed of 25, 30, and 35%, in
order to compensate for the apparent shift in the curve. The
assumptions for the analysis were as follows.
Starting Wood Moisture:
33% of fuel at 35% moisture
33% of fuel at 40% moisture
33% of fuel at 45% moisture
For wood in the 35% category no reduction in fuel moisture is assumed.
For wood in the 40% moisture category:
40% will drop to 35% moisture
20% will drop to 38% moisture
40% will remain at 40% moisture
For wood in the 45% moisture category:
20% will drop to 35% moisture
20% will drop to 39% moisture
20% will drop to 43% moisture
40% will remain at 45% moisture
For the original moisture content of the fuel the emissions are estimated
at 15 g/kg.
Moisture Content Percent of Fuel Emissions (g/kg)
35% 33% 13
40% 33% 15
45% 33% 17
99% weighted = 15 g/kg
average
D-66
-------
-33% x 100%
33% x 40%
33% x 20%
33% x 40%
33% x 20%
33% x 20%
33% x 20%
33% x 40%
weighted x
13
13
14
15
13
15
16
17
= "14 g/kg
The emissions from the fuel of reduced moisture content are:
Initial New Moisture Percent of Fuel Emis-sions (g/kg)
Moisture Content
35 35%
40 35%
38%
40%
45 35%
39%
43%
45%
Therefore the percent reduction in emissions due to the change in
moisture content would be 6.7% ( (15-14)/15). This result compares
reasonably well with the 10.5% emission reduction estimated using
Shelton's relationship for combustion efficiency and indicates that
the effect of fuel moisture content on emissions is significant.
However, the data indicate that there is some uncertainty as to the
actual value of the optimum fuel moisture content, although it is
indicated to be near 30%, wet basis.
Perhaps one of the more significant conclusions which can be
drawn from the data presented in Figure D9 is the decrease in emissions
which can be expected to occur if wood is burned at the optimum fuel
moisture content, as opposed to burning green, unseasoned wood (e.g.,
55% moisture, wet basis). The data in Figure D9 indicate emissions
could be reduced by 40% ( (25-15)/15 g/kg) for a given fuel load.
Assuming 15% of the current wood stove owners burn green wood and
75% of these could be educated to properly season the wood a reduction
of 5% (.15 x .75 x .40) could be obtained for wood stove emissions and
a reduction of 3.5% (.7 x .5) for total RWC emissions.
OQ '
Auburn University Research J
,.axwell, Dyer, and Naples .Tieasured creosote deposition for
different woods at different moisture contents. Although they
concluded that higher moisture content wood produces less creosote
several shortcomings in the test procedure n.ake it impossible to
-..-, . -ilize froi.i this research to draw the conclusion t.iut particu-
D-68
-------
"late G./.ission rate always increases as wood r;iui sti.rc- ccntcnt :_-
crtju333. rirst, although the test wos desi-^nec to n.casurc creosctj
rather than particulate emission rates, creosote deposition does
not always correlate with particulate emission rates. Secondly,
ond ,;,ost importantly, >::ost of the test runs used wood with noisture
;;*,'.t3nt3 .-.ell below t;ie norm \,\ ,,.ost nouith jlds. .r, ii,- .:
- Jili ..:,'<.. ,,ooc with '/,. ,...c. c.ii- tW"- o>' -!,. I., lo^i., ^Sf^
Jo,, which "is an insufficient differential upon which s"; >jiii i ic£.jit
oor.clusi'ins can oe based. One test used 't2 ,,..c. r,"i,ie lo^s . ut
..ci.c: of the tests of ,vood with n.c. betv.eer 25 ani. Z., ,.c. -s.\
nine lujS. Tnus the Auburn research carino: oe useo LW -r^-.. ;i^-
s iy'rnficant conclusions about how particulate ei;:ission rate varies
with wood i.ioisture content, at least within the moisture content
range of primary interests, 25 to 35%.
3. Direct Restrictions on n'ood Usage
The two strategy approaches evaluated in this category were
a) episode controls, and; b) emissions density zoning. Assump-
tions and calculations for both are described below.
a. Episode Controls
If emissions from residential wood combustion can
be reduced during peak pollution periods, then peak concen-
trations can be reduced. Several CGU,unities w,th air quality
problems associated with wood burning, request residents
to reduce or curtail wood burning during such episodes.
The chief advantage of such a program is that it focuses
on the time periods when emission reductions' are needed the
i.iost. In the discussion below, several such programs are
described and the potential benefits for the Pacific North-
west are calculated.
D-69
-------
/ i wL'-jLior^iit , iii... , ./. , cc rro-rcii.,
I.i 11C1, the .\ir i-'ollution Control Liv;3,oi, or .,^
Albuquerque Environmental Services Depart:, ient a^plieo for
and received a grant for $25,000 from the U.S. Environmental
Protection /"...ency for ths purpose of installing c telephone-
syste;.'. GP.VJ "pel 1 u'- .on signal light" that ',,ould ^rovide
w.'Cu. K oCCii3"iJ i if ". n r or. "i.e. t ; or, co cr.c pi.'^! 1 1_ 01 ''_r. ;i i _,
pollutant concentrations were occurring. jurir,:; H^l t 'c-
'Vollutior, signal lic;iit" '.-as install C'J ot, t'ne tor o
fool juilJiiv^ T, u co..'.; .>ji'C ! e 1 urea 5u^rGur,du<_ ._, ''is
T.ie signal lidhL -ic.i r, -/its covdru.j a 5 root Lid,,.L'Cfr
35 feet hibi',, anc L;;e signal liyht is shaped in the- for..,
of a candle. The lights colors are changed defending on
hourly CO concentrations. The light is operated so that
it is white when hourly CO concentrations are below 13 pp:.;
(Federal Standard = 9 ppr.i), red when hourly concentrations
exceed 13 ppin, and blinking red when hourly concentrations
exceed 26 ppm. At levels above 13 pprn, it is suggested that
individuals reduce their usage of fireplaces and autos and
at levels above 26 ppni a stronger request is made. Figure D10
on the following page shows a brochure which describes the
pollution signal libht system.
The systen, is operated between 5 ,j.r... and 11 p.;...
during i.iid-Movember through mid- January, with one individual
on duty adjusting the light based on hourly CO concentrations
recorded remotely. Thus after set up costs, system opera-
tion requires about 42 manhours per week (6 Jir per day x
7 days) or about SCO ,;ianhours per year (9 weeks x 42 hrs/'week
= 378), which at a loaded personnel cost of $20/hr would
cost about $7oOO per year.
Although the Agency perceives the signal light system
to r.ave beneficial effects in reducing wood usage during
D-70
-------
FIGURE D10
Albuquerque Pollution Signal Light
1 0 WHITE
RED
rft v.iflf - _^ ; )t 'sr/ Wf -ii* . I M^^tll Ik I /^
\-^j »i»Au.U)-jim iii.'J'i'/^'U FLASHING
Pig
^rflL ''ri I PRttiJfiKEMnMkflnMnfw^UK
HEALTHFUL AIR
UNHEALTHFUL AIR
VERY UNHEALTHFUL AIR^V
1HF CANOir - ALBUQUERQUE'S HOLIDAY AIR POLLUTION SiGMAL LIGHT
I In: holul.iy sunsoit is ,i iniiM of rnoccuring nighttime carbon monoxide problems The best way for
you in lie itwun: ol aic pollution conditions during this lim« is by chuck'nj.' l»te air pollulion .
InjM Hit! lu.litUy LANUU
WHAT III IOOK IUII
A i.liji>||n>i) i.oliti CANIUf will hn placdd on lop of a prominent building just south of Coronado
(Jniiim 10 lml|> you know vvliun uir pollution problems occur The color changes will indicate the
i oiulilioiib isai.li iiiylil during Hie holidays W« have unh«althful carbon monoxide conditions
.tlaiui hall ilu> inning "« l>«i:iiinl'ni>iiii 76b 743?
I Ins |ifo|«:( I is spoiisiiiiiU Ity ihb Albuquarquu/ Bernalillo County Air Quality Control Board.
ii LIIII.I. OII«HIII.III
0-71-
-------
vi^iSl-uL.' ^CrfiUoS , i-i.c o_. SliJI , Onlj ncli J<_'Ji' < wr-^"j,v, <_
CO concentration *;as ^7« lower during winter ^1-^1 tiic.ii rhe
previous year, but it is not currently possible to quantify
ho.; ,,,uch of this differential is attributable to differences
", i ..ioii.Lp, Jtcrcascs ;;, WCOG ar.c auto ust^e uecduse of tr'O
"i i^iii SjL-'.i,.,, or o'jCrvaioc, in xooti liSc^L- ror otnor r-jusons.
and lights, and $G,5CC was spent tc secure- installation
apr;roval fro;,, thi 11J foot hi^h dpartr.itiit bui Icii ric,.
Since 137C tlie .".issoula County /^ir Politic;. .\ju;i cy
has i"iac! ar; "cpisocs control" program under which r^s" u.-r,t3
are requested not to burn wood (unless it is the sole- source
of heat; when pollutant concentrations are high. The pro-
gram was modified in December 1981 such that curtailment
of wood burning is a requirement for househlds at the second
stage of "alert" severity, except for households which heat
only with wood.
An automated particle monitor (APM), purchased in
197o for $15,000, provides hourly average TSP levels, i.'hen
3
particulate concentrations exceed 150 yg/in and a meteoro-
logical analysis suggests that poor dispersion concitions
will continue, the Acency, ar.iony other actions,
1. advises citizens via public nedia of the ALERT
2. requests citizens to discontinue use of residential
solid fuel burners, and
3. requests citizens to limit automobile driving to
necessary trips only.
vJhen levels of 300 yg/m° occur and continued poor dispersion
conditions are forecasted a "WARNING" is issued which results
43
in the following Agency actions :
D-72
-------
i G r'i 7 ^ s s *j r. u i u I L; r '. v i n , 3 c*,, o
The liiscnarje of visible emissions fro,,, residential
solid fuel burners is prohibited, unless that equip-
;,tnt is ti:t only heat source-.
", o ;.;rscr, si.i'll cause, ..lie.,', cr o'lSciiarge visible
... 'ssi'jnj froi. : cij Pes i u-jM L; c, i sol iv.', fuel bonier
.-r.lssb ->.:', roSi'-i lit', a I :clic fj-.-l ;,ur;i'~;r is the
^ ^ i c _ cj i''" ^'_ ^ T ;o ci -. * t^ or o * \ '.-", s ^-. i c r ^ 111 ^ v < s ,^ i j
-.,." ss'.Cni oi.^M ,,:.;e ti'iv ^i,r tr. ^' .'.' r i r;..:,; i vcl^'
cistaLn i slriri'j tiiat the resiu&ntial solid fuel burner
is the solo source of heat. For sources other tlian
a resic'ent ial solid fuel burner, no person shall
cause, allo'.-: or discharge visible ei.iissions from
any source unless such source has a State or County
air ccntaiuinotion per,nit."
ilo "UARiiINGS" (second-stage episode) were issued
curing winter 1981-02, but the Agency did assess public
response to the requests for reduced wood burning during
the "ALERTS" which occurred. Dased or, observations of
whether visible siiioke was being emitted from 194 wood-burning
homes on six random afternoons per month, the Agency determined
that requests for wood burning cutbacks resulted in 36% less
"1
households burning wood on a voluntary basis.'"
In a survey conducted in Missoula in 1980 , 59% of respondents
said they would support a regulation banning wood heating on poor air
quality days. Over 70% said they did cooperate with the voluntary ban
during alerts. Thus although there is no experience yet with compliance
on "WARNING" days (+300 yg/m3 TSP) when visible emissions are prohibited
from wood burning households, a 75% reduction in wood burning under
these conditions is assumed for purposes of this analysis.
TSP levels from the APii are telemetered into a central
computer system. The Agency which accesses the State Air
D-73
-------
,'jv.-1 i 0^ . jfxcL. 'Ji>!.,/>_.,or, spent , i o, v^^u i t»r _.." -rc. i -.- .' i i r -
i..t.iii, t.i,iv-,i p r../v "i UCJG. u\_r.2f its wGyono t.'ic jt^ in^' '..w"i'_r_>i
systc-n. u.e., word processing capability, prii.i;n. Co.pc.jil-
ity, ;,,odel 1 inj, etc.). The two telephones which provide
air quality updates cost $2oC Initially. T';c v nual j^s:
j r !.,'. _ .; vj I i n J 3 I 5 c L, 0 U t v / Ci C / j L a r 1.', C C;''. , , i i Z i i. " i ". , V_
- ,-'--;,--, i i ^ . a-, , , ,,',,,,. _
-.,-'- >- , '- ^ i . i v, u . i L a i I j J c L .. _ <_'! i , j i! 0 i i . S / _ ^ - . . - ' .
, .^LL. -^ . uf O',,j professional's ti, c is re'./... r .L ...,)",,., i.:^
C/ ncnt!. ,, inter period to coordinate the syst-^ . r'or an
..;- .'^. ,i, i-.'iiiU'Ul labor costi ^30,^L. .' "!
Application In the Pacific Northwest
In Oregon, the Department of Environu.ental Quality
is prohibited from regulating household space heating equip-
ment. L However, the effect of requests to voluntarily
curtail woodburning can be estimated based oh experience in
Ilssoula. If a widespread public education campaign were
- II,,.V,CLIJ as ii"i i.issoula, it is estimated for purposes of
this analysis that a 33« reduction could occur in wood
heating on "episode days", which would yield a 33% reduction
in emissions on those days.
L^asec on a ratio of peak day concentration to average
i-/inter day concentrations of 2.5*, the reduction in average
winter particulate concentrations can be calculated, depend-
ing on the number of episode days.
* Larson^0 first identified this relationship which resulted in setting
24-hour particulate standards at 2.5 times the level of annual
o
particulate concentrations H50 vs 60 ug/m TSP).
D-74
-------
_,, i jowl, --'.ij o i .. . 1 ". J I .. ,. . .,. i _ : t " " '"]" ^
w r c j,. i c v. 1 ,..' _ . i., . v c . . 111 c c.- r
i L-f wonCiritrat i oil!
ir (33* reduction) X 4 days/150 oays X
2.5 overage concentrations - 2.2/.-.
I .!33l, flocuction) /' i days/150 cays X
<_; . ^ V >:; \ C C' i i C ".. i \. r a c " 011C- - 'J . '^ .
\-o,, ., J'-Uw L , Oil / A l-> UC._/b/ I OO UCjii ,x
2.3 uvc-rUj. cjncf.ntr-.it ions - C.3.
v o. ._ v.'.. ^ L i o i i , .\ i ; '-i uy s / 1 o - L. iy s . i
2.^ "..'.jrc.^^ jxiiCffiCrut i oni, = 1_.^'
(33. r;:-'Juct i orij X 20 day'3/15C days X
2.5 average: concentrations = 11.1«
(33;.' Ue^-LiCtion) X 25 days/150 days X
2.5 cVfcr3_,e concentrations = 13.2%
Thus for an area nith typically nine winter days with
3
participate concentrations exceeding 150 y^/:,i , a 33% reduc-
tion in wood burning (resulting from voluntary requests)
should reduce the impacts from wood burning on those episode
days by 33% and average v/inter wood burning impacts by 5%.
b . Eiii'iss'ion Density Zoning Effect On Hi,.issions
Er.,ission density zoning is sor,;etir,.es sucgested as a means
to limit emissions froi.i pollution sources such that acceptable
pollutant concentrations are not exceeded. Clearly this approach
has greatest potential for large emission sources who must obtain
a pollution discharge permit as a condition of operation - for
small sources such as wood stoves, if limits, were to be set which
limited the number of stoves per square mile, there would obviously
be compliance and enforcement problems. Oregon statutes which
D-75
-------
^ U : . 1 ... . - U 1 1 V_* ~J u C ^ L. / -y:. , * i - ^ . J I - ^. -J L , '' . ', V , L- C ^
less, i,1 tile discussion jelo.», JSL iniates arc ..,a>^ ^r ,".c. ,,iicr,
future ei.iissions woulc be reduced, if stove installations were
to be 1 ii,,itec to 1984 levels, assuinin^ levels of coir.pl iance. The
jsoi.ncites arj basec, on th.e prcjecticr, of future . jud usa^-1- fro.,
Icor-. 3 fur r;ortlc.tic, boattle, ar,c S^^la, j. To!:"!c ' U Jelc,, si:o.,s
c.:iL. 2000 if ne;< stove installations ..ere net Kfcr;,.ittec aftt
' C " " -. 1-*-, r* ^- -i" - f f- -'
.. D's,/. CGiij-liGLilCt? id uS ^un.icU .
TA:L: j 14
Deduction in Expected 1230 arid 2COC \^iC E,missions
If New Stove Installations Were Not Allowed After 1984
and 50% Compliance Occurred*
Emission Reduction Emission Reduction
City by 13CO Coinpared to by 2000 Con-pared to
Expected 19SO Levels Expected 2000 Levels
Portland 3.2?^ 27.3%
Seattle 3.9% 3.9%
Spokane 3.7% 13.7%
Since the ^rc-ctest crowth in v:ood burning in stoves is pro-
jected for Portland, if that growth were somehow precluded then
the greatest emission reduction would occur in Portland. However,
due to compliance problems, legality problems, and. general public
nonacceptance of such constraints, no practical emission reduc-
tion benefit appears achievable by this strategy.
Based on.,projected growth in the wood usacje by stoves/furnaces froi;.
Task 31.
D-76
-------
eratin., Practices
t"i ri;, procedures c^.i .uve a ci^ri'if iccr.t inf lue'icc 01. jurtii
unit emission production. In the discussion oelow, assumptions and
calculations arc preseiitoc for the fcllovinj potential strategies:
1. Initial selection of jurri.n^ units - "5;m^"
.1 p c? f -i \. i n __ i c c i i i 11 i, v. e . G c " r i c i .. i c i * b
ii . ^"! SCOUr a'.., 1 I i^ />"i r C "! jii i, ^CCV't J]ji. Tot. i Of i
b. C'aarging Larger ^iec^s of .,cjc
Pcrioc'.c InspecL iori of ,->.l IC,L. -,. ,ent
1. Initial Selection uf Jurriin."; Lii'.cs - "jii"!fi[,"
The proper sizing of a wooci stove is sometimes advocated
on the basis that a larger stove often produces so much heat
for the room in which it is located that air supply must be
severely restricted - resulting in poorer combustion efficiency
and higher creosote deposition and air pollutant emissions.
Conversely, a smaller stove is alleged to "burn hotter" with
resulting higher combustion efficiency and less creosote and
emissions. In the discussion below, the effects of stove size
on emissions are analyzec based on a review of the available
information on how operating factors influence emissions.
In summary, it appears that li:e cniof benefit of smaller
stove sizing aerived from the result that si.aller amounts of
,,oo(J are generally charged when reloading oue to the smaller
firebox capacity and smaller loads result in a hotter fire with
better combustion efficiency and lower emissions. Regarding
the effect on "burn rate", assuming that a room's or household's
neat ing requirements remain constant, v;hen a smaller stove is
utilized, it appears likely that operators will generally still
seek the same heat output (in Ctu's/hour) and thus the same
volume of wood can be expected to be burned per hour (neglecting
D-77
-------
- :}'jrr. rate effects
- Size of fuel charge effects
- I,,CGrivbrn er.co ";:>^i.;3S
- f^ss'ibli ef f ',c i ;v.^._. JM.;?_'.;
,,«tc cTTL-CuS
If the Sciii.e rooiii or house iuc.ti.i^ rj^u i re.,,<--nLs jAist, t!ie
sj.. ;.> iipproxiii.ate number c~; utu's/hcur j.r;j required to ,,,L. i r,tair,
.iw1, c..iCcf jiirn rate \cxi-,res S'?u ir, i\v ..vxuu/ I'iCL.r/ (,ir_ i,&f;ef its
Cc.nr.ot ^u attributed to Lurr; rate ciiaf,_js ./her, sccve downsizing
occurs, unless the charge size is also reduced.
Fuel Charce Effects
Research by Butcher indicates that the intensity of a fire
is what most influences emissions. Intensity of a fire can be
thought of as the heat release rate fron, ongoing combustion
divided by the amount cf vvood charged. For the sa;.;e wood charge-,
ourninc; with a greater heat release rate results in a more
intense fire and less emissions and 'for the same heat release
rate, a smaller wood charge results in a more intense fire and
loss emissions. In both the above cases a more intense fire
i.aans there is r.ore heat released per pound charged. This rela-
1C
tiunship */as described in equation for,,, by 3utcher in 1S79 :
y = 1C.34 ffi/q - 1.18
where
y - emission rate in g/kc
i,i - fuel charge in kg of wood
q - combustion rate in 10,000 Btu's output/hour
D-78
-------
c r\. o. j. i i. j c t a r j'_ j i i -_, , i..j i i«i ~; i
on stove tests where carbon ;,,uioxid draft ,,:ode of
burnincj."
"Table II coiupares the two tests, demonstrating
that, as the wood inventory increases, the
emissions increase. Although -the burning rates
for the two tests were essentially the sa;;;e,
the large charge resulted in approxii.iately twice
the emissions."
"Stoves that keep the .;uod fro.,, pyrolyziny by
isolating the wood inventory froin the heat
during combustion should reduce emissions.
Since most existing stove designs do not isolate
the wood inventory, the only course open to the
operator to reduce emissions fron this KicdiairiSM
is to ado srr-all quantities of wood i,,ore
frequently."
Size of Fuel Charge Effects
No change in burn rate or combustion rate can be attributed
to a change in stove size, but a smaller stove will have a
smaller firebox which will mean that generally swaller amounts of
wood will be charged each ciu.e. This means ''r;:" in the above
equation is si.'ialler. Thus if a stove with 25% smaller firebox
capacity is installed, it can be assumed that average "charye
size" ("in") will be reduced by 25% which reduces the emission
rate by 25%.
D-79
-------
, . i JU>- ^l- Tl .'_'*.,- Uj ''. Jj , 0 U Of OH'jJj
Cjii ^e :. Vc, I LKil^'u tc L.rof, ->_, <:o«:
vl.,,ibiiun Factor; x ;'>-ooc ./urt,ed Per bay/
^Tc., i TCP/'r'J r/OO^ X k'_, ..OOC/Dc.iy
j ~ Oil s ^0 ri >,
r _ jw i L'_.; c _.!.... i i _i' ~j r i c^ i c..oi ^c. b i .__' i" v. o, c. i i cr stove .
. L . i v- _ i r .' O c. ~ ^ i T L-
.j . o'v _'uii\ uii i or.t t j r^loaL. t.vj stuvj
'Ciiij' bti-VG u, ~, jrotors iiKC Lc t-iji.'.^tr tnc
_. ; r oUjj^l^ i.1 .!_,; - -; -- ^s ill rci..cir <:\ Lfit , orniiij Cine tiic
fire .'.ill not f.avt: cc jt ristartec. For iicast-nolub whtre all
uciilti ae:ierul Ij ,,ur.,, 6 ilo,/ burn rate Llirou^iiout the ccy also
is cesirable.
i;'ncn « Sn,allc-r stove is utilizeu, since the firebox volui^.e
is Si:'.;ller, lesser ci^ounts of ,:ood can be cnargec eacn tine and
for the sfii.it Jurn rale or neat output, reload "in^, will be requireti
on a i ;ore frequent basis. This issue is the factor which i,.ost
encoL,rayes larger stove purchases by operators anci forms the
^rectust. bcsrrisr Lo chancing behavior so that individuals cur-
Two utlier ruclvr'S ,.ork >,o encoura^ s,..c.cr stove s'uin:,.
A sculler stove- contains less materials and tnus generally costs
less than a laryt-r stove, assunins equal cofr.pl exity of desicn.
Also a smaller stove by virtue of its greater burning intensity
(Jill ^er.i.-rcllj ourn i, otter and have less cre-osote deposition.
Stove manufacturer's representatives acknowledge i.iany stove
purchasers' desire for lone burning capability in a stove. At
the February 15>o2 Jooo Heatinc, Alliance Trace Show in Louisville,
D-80
-------
>. u 't L L' - '. j , r ' i. *J ' i _, v.. ^ , r -j i ^\' '^ . j _ u ^ ^ c ^ L *i ^ .1 . . ' o ^ ^ -
L c, i !' cL c. ju rr, i oi' T. ~ > o n r b . i nu i s u j L c t i" _ 1 c. t.. > ^ ric;,;. - i; .
i/ill liiuit 1:12 co_;roc- tu which stove operators '('ill b.e vrillir
to "down s'l^o", unless curitinuuus feeding systems sucti es ciii,
rs !,.v/e s ' r; > !"..; :...t
c-i"f i c~i or.-j . .. "..oLter" or .norc >iitc;,sc Jur,.
;. i i . i~ r ; ci-_j;i~y c<>c.n~2i,, cnan^es i". *.:... "f\.,
i - .^j
<- v ; r :
limited, unoer i,-....,- conditions a hotter or .,iore intense ^-un:
v/ill lead to hotter stuc;< .jas temperatures and a lesser' h^ai,
transfer of the adcinonul Jtu's in the.hotter stack ..as. This
i.eans that a hotter burr. ,vi 11 not necessarily result in Higher
overall efficiency since the combustion efficiency increase ;;,ay
be offset by a decrease in heat transfer efficiency.
Harriett has cldi^ed that overall efficiency generally pla-
teaus between a 2 and 4 pound/hour burn rate. This is approxi-
mately the burn rate rarKje «'hich is believed to represent typical
practice in Western Oregon and Washington. Also, efficiency
testing results for both a catalyst stove (Webster Oak) and a
seconcc.r> cor..L-st;^r stuve vvJ-otul 2C1 ) s'r.o,. that these ^nits
have higher overall ef^'.c ier.cy at lo.ver burn rates tlian higher.
Although these stoves i,.ay represent a cifferent category of stove
behavior because of the secondary con;bustion v
-------
v. '. iiO'L we .M"!''I'M TOf CC.T', .-. Ii , DUu f i!iijc' u - C '. -
c.cd'i t'lO.-sal "cov/ns ii in.," of 1C^ by TJDO am 13
uccur us a result of a ,strung public educatioii ..ro^ra, ,/hic'.
,.ojld yield an ocd it'ional ei'issicn reduction o^ 107 !,_/ 1'33'3 e;;d
reduce beyond that of 5 percent by 2000. Since wood stoves/
i^T ^..J^L!- I ^ -, wJ oil t,«.v, C'i i' i S S i 0 f1! 1> i-1^ ullu i Cj ~ t _ *. ^.j t. . ^
j',rc.tj /sirt'i^ht G^ordtirij Of Jcu'vijj
v,h'ire.turs often restrict air supply c;i airL.fiiL stoves,
either as a ;..euns to li; it a stove's heat output so ",\~t ^ui,,for
able roc,,; temperatures are not exceeded or for convenience to
extend the length of tiir.e between refuel in^s. Restricting air
supply s1o\i's dovi'n the burn raie since the an.uurit of oxyjeri uya.
uL.le in ti.e conbustion zone limits the rett of cu.,ibui!; ion of
tfit ',/ooci. The effect of Durn rate or, total emissions is dis-
cussed as a Key Topic early in this Appendix.
.X&jdrcing airtight operation, it appears that ci scourj^in
airtight operatiori, or increasing born rates ^nlj re-,oc^s tocal
^..iissici.s if the operator burns for fewer '-.ours per L.c,y '..hen
rit shifts to a faster burn rcte. Unless an Operator recuces
the nui.iber of hours per cay that the stove is in operation, the
benefits of o lower emission factor from a higher burn rate is
counterbalanced by the increased amount of wood burned per day
»'hen iiiore pounds wood per hour are burned. This relationship
i s shown below.
D-82
-------
;; _ .,,/q
.constant) (wood charge in K^/
(utu output "in 10,CCC
JL i" '.;,'! r_~. tu .3 v-<^u.j 1 -'I-. i'rji. 1 tj ^ ,N^/ liCuT tfij: - '
si oti fuctcr '. s iiC-lvei.. sincv the "q" tern which is m the
!"ioU.r jf Int. JL.I, ^.t iv. i is uv^bleo. iiov.-ever, whereas r. !.
. .1; i..;.t I.1 ^^r;, ^t .. 1 ;;-/. iour Lurn r^te, : t .
:,o«rs at. w J x^/i.our ^urn rate. If the
o
,;
rdi. ". ui; so Lr.ct i:C * s H'illiny to burn b hours
the rate ai.d then riot operate the stove for 5 hours, the emis-
sions in that 10 hour period v.'ill be halved. This, hov.'ever,
seei.is unlilcel^ to occur unless a heat storage r,,echan;si., is
employee! since the house would then have no heat source for a
b hour perioc.
Coiiifort factors also ,iake it unlikely that operators /.'ill
DC .villinc, to s;,ift Lo a ourniny hotter/not burniriy cltert'.at iiij
pattern.
If ourn rate is doubled, the stove will putout tv/ice as
i.iuch !;eat to the room where the stove is located w'nicn is likely
to M.ake trie rooi:. unco, ifcrtebly hot. Quite siir.ply, operators
restrict air flov; in order to control rooi.i or household tc,;.pera-
ture, an.G it appears unreasonable to expect that many vvill shift
to u burninc, hotter/not burning alternating pattern, because
that will result in lanje swings in the ter.iperat.ure of liviruj
areas. Since such a oelsavior change appears unlikely to occur,
tnesc autnors assign no eii.ission reduction benefit to this
strategy.
D-83
-------
Lar.-cr Pvoces of '..ooci
barnett and Battelle have noted that smaller s:zcjc_
lofjS burn v.'ith higher emission rates then larger logs -..hen burn
rates are held constant. oattelle's results are based on CO
and total hydrocarbon e;..1 ss i ons . Caltc-lle explains tl;c pf.Ciicut
ion as follows:
"The size of v.-ood has a large effect on the
rate of pyrolysis. The smaller pieces of ,,-oou
result in: a shorter distance for the pyroljsis
(Ji'CviuCt.s to GiffuSL, a 1 ar-jcT M/rTjCv or 3 a to
r. 3S Tc"L", '^, iti'J u
..
to hoot Liie entire j.>iect of ..-jOu. .....
Jarnett hypothesizes similarly that the "surface area to
«ood volume" is the key parameter:
"... results indicate that log diameter has a
large effect on emissions. Undoubtedly, the
surface area to wooa volume relationship is a
key factor. Thin logs have a large surface
area volume ratio. Therefore, these logs heat
up relatively fast and then release their
volatiles at a fast rate. This process is
further aided by the large surface area of the
logs through which volatiles are released."
Sarnett developed a best fit equation for a thin-welled
convective heater operated with a stove surface temperature of
?pn'1 p
^uu r .
y - 11 .3 - $.9 [log (log size}]1"1
where
y = TSP emission rate in grams per pound
log size = log diameter in inches
On a grai.is per kilogram emission rate basis the equation
can be converted to:
y = 24. S - 21.8 [log (log size)]
D-84
-------
:-. 1 . - 15 ...I.. _,, _s L-, . irr, ,-,- .'S. .j. ~, :... : .
Colui,.r. 4 sliows the ',.' emission reuuctiun v.iiic'n results fro:..
i licrcusi riCj the soseliiie loj size by 2". As can DC- seen,
"i i,croasi i.j "lo^ size o> C" is predicted tt. cecrOuSt ci,,,ssion rdtts
Lo.-, S-ize Preuictcu Assumed 109 Size Resultant /.
(Inches; Emission Factor Chanye From Emission Kate
.5
T
(L
3
4
(ii/kc,)
31.5
2 4 . 3
13.3 2" to 4"
K.5 3" to 5"
11.7 4" to 5"
Decrease
35%
33%
"- /
D-85
-------
fl j SCCV'J uf/Cru Lwf'l i,C ii"Lf~*;Gj" -. : . - , - - -
i. ,re3 little SC..JT ,f ,;e o;> V; d ' r ,;CTl - > '.c', I:-;,; :,, '
tir.c, requires less work. Since such a behavior change coos not
result in any eoditional inconvenience to the operator, the
chances of wKreasin: the average pi see size- via educationol
'rorfi,.iS J>|js_ r.j-:^.
trie i r iivorc-c rj"iOCe Si^c.1 ./Co uic
oasis, a 13" emission reduction ,7roi : t^.e stove r:.,u1ot.or. :oi.. 1:
J^ c C II i c V C L . , 1 1 1 1 I i c t I i 0 r/ c i" a L O f j u C i" . T 1 C i_ i - w- - A . - k. - : - . > /
;.ssu:..'ir, 7,;,. of t;,to! ....'- e..,issicn:, are attributable to stoves/
urr.aces, t.iiS affords ^.n 11. 5«
Periodic Inspection of l\t
-------
c.fttT deterioration, Because of "inert o", loci-' of r-ercc-t,Lior.
of catalyst non-performance, and because of the S75 to ^100
replacement cost.
Second, as stove ciesi^iis u-_cc,,e , c-v s -fisit'. veV optimized,
".nor-dOScd 3tove ,,,a", ntetic-nce ,,.a.> JDCO.,;: -i.^'ijury i.j ; ^-..i^oir-
I1--"1.,"!,
.->- - ^ ;i- i i> i _,!! i wv - i v. i f. jr i ^r, o.i1.--1. i , _- ,, /_v.rs ^;, ^c c
i.icr-j likely retirement for stoves .','(.: ..J. jo. ^ust'iO" efficiency
v/ith intricate air introduction arr6fi_,^,:\u_, Lhan for simple
stoves '..ith ^Ow coi.iw-jst i on cf fi c i onc_,.. , , J.>-.-ct",on ^.ro^rc.T,
i. 'ijiit Je cole to "identify unJ jorr.ci. - _
Tirircly, if an inspection program ,,c;^: to foc^s on counsel-
liti'.j the operators whose chii;.ney stacks e/i't jspociclly Jense
pluuses, they could advise those operators on ro,; they might
change operating practices to reduce creosote deposition and
stack emissions. Focusinc, on "\vorst offenders" could yield the
greatest benefits for the tihie spent - the 10% of stoves which
produce greatest emissions per day probably account for more
than 20% of total stove emissions.
Despite the above potential benefits fros;i inspection pro-
;;rai,iS, several factors make inspection programs unlikely to be
implemented as a government-imposed strategy in most co.;*,.unities.
First, some states such as Oregon proliijic ervirom.iental agency
regulation of home space heatinb de«/ices.l£" Secondly, there
v/ould be significant public opposition to a program under which
inspectors had authority to enter households and require equip-
ment modifications. These factors lead us to conclude that an
inspection program is not a feasible regulatory strategy for most
communities for reducing emissions and thus no emission reduction
credit is assigned to this strategy.
D-87
-------
I
00
oo
c' o
i. r:
c
-s
CL
c
rr
If
1
Ci
^*z~
rt>
CV
r
C
r-i
rt
~T
rs
1/1
CJ
^
fl
f-^-
Wx
__.
7'
t/1
T.
n-
o
rt-
o
rr
rr
T
t }
n.
rt-
-5
fL-
O
r-
O.
C"
fl
n
0
-5
ro
OJ
c/>
ro
0.
o
ZZ-"
c
^
n
ru
{/>
n
0
-^
O-1
7"j
ll'
~
.
LO
0)
i.
C
00
r.
zr
i/i
-t .
a>
o
c
c
c
CJ
Hi
a
CO
T.
ro
o
(-r
i.
O
^3
~o
^
c
tr '
~s
C->
-
"Z
(t*
"j
a
a
<"
f ;,
-s
_.
~
~^
1
re
i
i" (r
L/* C
< r\.
c
!.' <
I ' 0.
r *-
c/)
c r.
-n *)
C Ci
rs
C1.* ^-J
i" *<
c-
- . . r/
'- . .
vi C' ^
n~
c n^
-s
^/
0, -ll
-h .
(. -5
r- O
t
r
-^
; (ji
o'! cr
-t. -i
I. O)
<' - -^
. " O
f"
c
rj
~s
f_^
C-,
L'l
f ')
n
C"
t -4
-s
O
o
cr
01
C
3"
6
__ j
c?^
en
j-
_>.
rt
(/i
O
t
- >.
(^
h
rj;
rr>
1
rr
rc
TJ
r+
^
t^
f j
_;~^
£-
"I '
-s
C'
in
O
O
1 CI
rr
ro
c_
!.
l/l
O
c.
-t,
c;
ro
*
cr
c:
-s
33
i.
r?
cr:
O
_fT;
cr
t.
c:
f
ro
r;
(-h
. 1.
.
(T
"
;
<5
o
O-'
( u
fl-
i i
T
c -
~s
0)
<-'
o
r;
i j
CO
o
-ll
rt-
O
^j.
-s
ro
in
_j.
rs
in
_ j.
ri
cc";
i
O
-h
C-!
^"
'.
t
<^
a.
^
ro
i
IT!
rs
i/ 1
t/t
r
c
r-, ;
n; r
CJ
c
--s
C-' f
c
0 r
' C
OJ
rt X'
O -!
f: C,
.
:" f
- ' rt-
rl- (';
(/>
I/* C>'
O -^i
' TL
r r
r. <-
t,
C - .:
Co (./>
i ~x
f:
r r.
r.
i i
ri C
-^ :'
C 1
T) c
^
r~ ( r
-^
1
-------
APPENDIX £
,. - revert describes the Keppner-Tregoe evaluation process.
;. . ;ST CRITERIA
All fifteen strategies were judged to satisfy all five ,-,U3T
criteria described in Section III (Table 1), with the following caveat.
Implementation of some strategies or strategy elements would require
er,acting or adopting specific legal authority (e.g., mandating weather-
-.zation of homes) or establishing financing programs (e.g.., weather-
ization loans). Such authority or financing would have to be "in-place"
before a strategy could-be approved by EPA as part of a State's Clean
Air Act Implementation Plan (SIP), thereby "meeting all legal require-
ments established by the Clean Air Act" (MUST criteria #2). The final
fifteen strategies have some precedents for all or most of their major
control elements. Accordingly, these strategies are considered capable
of meeting MUST criteria #5.
II. WAiJT CRITERIA SCORING
The general process of assigning WANT criteria scores was
described in Section III D. The twelve WANT criteria to be used were
described in Section III (Table 2) and their weighting factors in
Appendix A. An example of a decision framework for assigning scores
to strategies for a particular WANT criteria was described in Section
IV 3.
-------
Final fifteen il'.,'C Control 5'cratcjifcs £vclj^:e^
Strategy #1
Strategy ?2
Strategy #3
Strategy rf4
Strategy #5
Strategy #6
Strategy £7
Strategy #8
Strategy #9
Strategy #10
Strategy #11
Strategy #12
Strategy #13
Strategy #14
Strategy #15
Testing/Certification as Prerequisite to Sales
or Installation of i-iev; Stoves/Furnaces
Strategy ?!, with 33% Tax Credit ;S400.00)
Testing as Basis for Handatory Labeling of
flew Stoves/Furnaces Prior to Sales; Label
Specifies Emissions Performance and Efficiency
Strategy #3, with 33% Tax Credit ($400.00)
Testing/Rating by RWC Industry Trade Association
Mandatory Weatherization of All Households
i-landatory Weatherization Only for Households
Installing New Stove/Furnace
Firewood Moisture Content Controls
Stove Sizing
Encourage Larger Firewood Piece Size
Require Underfire Air Source for New Fireplaces
Episode Controls
Research and Development of Improved RWC
Appliances and/or Practices
Encourage Alternative Fuels
Periodic Inspection of RWC Equipment
E-2
-------
This unu sir.nlar frai. eworks for each »;Ai;T criteria are d
u-alc1.., in explaining how ..AM criteria scores were ass-.cjnec to each
of the final fifteen strategies. The resulting w'AiM criteria scores
are estimated in Table E2. The total scores in Table £2 constitute
a ^rel ii.ii nary ranking of the fifteen strategies.
Tir.s preliminary ranking becomes the final ranking, unless
^Justed based on significant adverse consequences (risk factors) of
,,,/ic...eniation of strategies, deteririinec as described in the next
section. There were not such adjustments made to the preliminary
r~ariK i ng i n Tab!e E2.
The following twelve subsections describe the "satisfaction
levels" used for each WANT criteria, to help assign scores to each
strategy in a consistent manner. Accompanying notes describe examples
of key considerations in assigning most scores.
A. VJAiJT #1: Reduce RWC Emissions'Per Household
This criteria reflects the degree to which strategy would
(potentially) reduce RWC particulate emissions per household.
Satisfaction
Level
Fully
Jell
Moderately
Poorly
tJone
Possible
Points
9-10
7-8
4-6
1-3
-0-
Conditions for
Reduces
Reduces
Reduces
Reduces
Reduces
RWC
RWC
RWC
RWC
RWC
Emi
Emi
Emi
Emi
Emi
Satisfying This Level
ssi
ssi
ssi
ons
ons
ons
ssions
ssi
ons
by
by
by
by
by
>:30%
10-30%
5-10%
0-5%
0%
Scores under WANT criteria #1 were based on estimated emis-
sions reductions achievable which are summarized in Table 7
(Section V) for most of the fifteen strategies. Only Strategies
#1 and #2 afford >30% reductions in RWC emissions, and only after
-------
TABLE E2
Keppner-Tregoe Scores for Final RWC Control Strategies
vs
All WANT Criteria and Risk Factors Assigned
WANT Criteria1
1. Reduce RWC emissions per household
2. Reduce no. of RWC households
3. Widely applicable/effective
4. Maximize public acceptance
5. Discourage worst appliance/practice
6. Minimize consumer cost
7. Use proven technology
8. Minimize circumvention
9. Maximize agency feasibility
10. Encourage innovative technology
11. Minimize free market Interference
12. Promote conservation and
renewable resources
Weight
Factor
13
13
10
9
9
6
5
4
3
2
2
1
Final RWC Control Strategies Selected for Evaluation
1
9 117
8 104
9 90
4 36
8 72
3 18
4 20
6 24
3 9
7 14
1 2
2 2
2
10 130
5 65
9 90
5 45
9 81
8 72
3 27
9 36
4 12
9 18
3 6
2 2
3
7 91
3 39
9 90
8 72
3 27
7 42
6 30
2 8
5 15
4 8
7 14
2 2
4
8 104
1 13
9 90
9 81
5 45
8 48
6 30
4 16
6 18
6 12
5 10
2 2
5
7 91
3 39
6 60
8 72
3 27
7 42
6 30
2 8
9 27
4 8
8 16
2 2
6
6 78
7 91
9 90
2 18
2 18
4 24
9 45
7 28
4 12
2 4
2 4
10 10
7
4 52
9 117
7 70
4 36
2 18
6 36
9 45
3 12
4 12
2 4
2 4
5 5
8
5 65
2 26
7 70
8 72
5 45
8 48
5 25
2 8
8 24
2 4
5 10
3 3
9
6 78
2 26
6 60
8 72
7 63
9 54
6 30
4 16
7 21
2 4
8 16
3 3
10
7 91
2 26
7 70
10 90
5 45
10 60
6 30
6 24
9 27
2 4
10 20
3 3
11
2 26
3 39
3 30
4 36
4 36
6 36
5 25
5 20
8 24
4 8
5 10
2 2
12
4 52
3 39
6 60
7 63
5 45
8 48
5 25
3 12
7 21
2 4
5 10
2 2
13
6 78
2 26
8 80
7 63
7 63
6 36
5 25
5 20
5 15
10 20
7 14
5 5
14
4 52
9 117
7 70
2 18
7 63
8 48
9 45
7 28
2 6
3 6
1 2
3 3
15
1 13
5 65
7 70
2 18
7 63
5 30
4 20
4 16
1 3
5 10
7 14
3 3
1
WANT Criteria Scores:
Risk Factor Scores:
Ranking
All MUST Criteria have been met.
508
114
2
535
139
1
438
40
8
469
85
4
422
0
10
432
70
9
411
35
11
400
24
12
443
45
7
490
45
3
292
40
15
381 445 458 325
50 0 56 70
13 -6 5 H
E-4
-------
2000 and 1995, respectively. Strate-jy //4 achieved 20% by the
year 2000, and so scored ^. Strategies ~3, ?5, and #10 all
scored 7, because their emissions reduction potential exceeded
10%. Strategies #6 and #9 had 7-10% emissions reduction, scoring
6. Strategy £13 also scored 6 because R&U is the key to the
success of i.iany of tne best strategies, through development of
test procedures, cleaner stoves, ind better operating practices.
Scoring v './ere mandatory weatherization of only households
installing a new stove (Strategy #7) and episode controls U12).
Strategy #14 (encourage alternative fuels) scored 4 because
restricted v/ooc supply restricts r;',,'C, and because combustion
of conventional fuels v.'oulo einit less particulate.
8. WANT #2: Reduce the Number of RUC Households
This criteria should reflect whether a strategy would dis-
courage new RUC households, or encouraging existing households
to quit RWC.
Satisfaction
Level
Possible
Points
Conditions for Satisfying This Level
Fully
Well
Moderately
Poorly
None
9-10
7-8
4-6
1
_o
-0-
Strongly discourage new RWC households;
or encourage existing RWC household to
quit.
Moderately discourage new RWC households;
or existing RWC households to quit.
Mildly discourage new RWC households;
or encourage existing RWC households to
quit.
Little or no effect on number of RWC
households.
Encourage new RWC households; or existing
households to increase RWC.
-------
Two strategies were considered n.ost likely to strongly
discourage new lU-.'C houseliulos, or encourage existing households
to reduce or quit RWC - weatherizatlon of only those households
Installing new stoves (Strategy £7), and encouragement of alter-
native fuels (Strategy #14), primarily due to its restrictions
on firewood supply. Close uehind, scoring 'J, ,.u. Strategy #1 ,
,.r,ose restriction of stove sales to certified units, with no
subsidy for purchase, could u.ake new stove purchases costly enough
to ciscourage new R'/,!C households, leatherization of all house-
nolcis scored 7, because lower heating requirements would make
u.'C less economically attractive vis a vis conventional fuel
use for r.;any persons who -consider ui'.'C a means of reducing their
conventional fuel bills.
Strategy #2 could mildly discourage new RWC households
because new stove purchases are limited to certified units,
although the tax credit should keep the price reasonable.
Required inspections of RWC households also could discourage
people who would dislike this as an invasion of privacy, and not
wish to be subject to possible mandatory maintenance costs or
civil penalty. All other strategies were judged to have little
or no effect.
C. WANT #3: ..'idely Applicable or Particularly Effective
This criteria reflects whether strategy would influence
a high percentage of RWC appliances or practices, or strongly
influence a major segment of them.
-------
Sat i sf action
Level
Ful ly
i.ell
i looerately
Poorly
Possi ule
Points
9-10
7-8
4-0
1-3
Conditions for Satisfying This Level
Applies to all or most RWC appliances
or practices.
Applies to many RWC appliances and/or
practices.
Applies to significant fraction of R'wC
appliance or practice categories.
Applies only to a few P\'..'C appliances or
practices.
ione -0- No effect, not applicable to.
All strategies scored 6 or higher except Strategy #11,
which applies onlv t.n npw fireplaces. Stratenies #1 - #4 all
.scored 9 because they would affect every stove/furnace sold,
neglecting circumvention. Strategy #5 was considered less
applicable because Trade Associations might not require all manu-
facturers to participate. Mandatory weatherization of all house-
holds (Strategy #6) affects existing as well as new RWC house-
holds, and is obviously more widely applicable than Strategy
#7. R&D (Strategy #13) would affect many of the leading
strategies themselves. Moisture controls (Strategy #8) poten-
tially affects all RWC households and both stoves and fireplaces,
but reliance upon voluntary compliance will reduce its effect.
Benefits of encouraging larger.piece size (Strategy #10) do not
extend to fireplaces. Inspection (Strategy #15) affects only
households with stoves. Encouraging alternative fuels might
not affect households with assumed wood supplies. Stove sizing
I strategy ffy; would eventually aftect many riousenoias, arter
many years. Episode controls applicability is diminished by
its voluntary nature.
1-7
-------
-. '..'.HI,! #4: I'.axir.nze Public Acceptance
The intent of this criteria is to reflect acceptability
to the general public and second to acknowledge significant
support or opposition.
Jacisfaction
Level
Ful ly
..£.'11
i.oderately
Poorly
None
Possible-
Points
9-10
1-Z
4-6
1-3
-0-
Conditions for Satisfying This Level
Fully acceptable; some significant support;
no significant opposition.
Acceptable to r,,ost parties; some support;
no significant opposition.
Lukewarm acceptance; ir.ost people don't know
or care; or, offsetting support and opposition
Acceptable primarily to environmentalists;
average person wary or opposes.
Not acceptable to many; strong opposition.
Likely public acceptance was deemed highest for Strategy
#10 (piece size), since it offered significant potential benefits,
at no cost, and with less work (less splitting of wood). Testing/
labeling plus tax credit (Strategy #4) scored 9, because consumer
options are not limited, but better consumer information is given,
along with an optional subsidy for purchasing cleaner stoves.
The other two labeling type strategies (#3, #5) also preserve
all consumer options. Moisture controls (#8) and stove sizing
(#9) also offer benefits with relatively little inconvenience
or costs (down sizing average stove size should save on costs
of equipment). Episode controls (#12) at least on a voluntary
basis, and R&D (#13) also were considered relatively easy to
win public support.
-------
Restricting the public's choice of stoves (Strategies #1
and #2) will not likely be popular, but proponents should partially
offset opponents. Mandatory weatherization of new RWC households
(Strategy #6) won't be widely popular, but will similarly have
some strong proponents. Requiring^underfire air for new fire-
places would affect home builders, but most of the public would
be relatively insulated from its effect since it 1) only applies
to new units, and 2) costs would be rolled in with entire costs
of a new dwelling. Mandatory weatherization of all households
will affect far more people and be significantly less acceptable
to the average person because it is a substantial mandated cost.
Strategy #14 will be unpopular for restricting firewood supplies
and was scored 2. Strategy #15 also scored this becasue it
required entry into private homes, and potential required
maintenance costs or civil penalties will be unwanted.
E. WANT #5: Discourage Worst RWC Appliances/Practices
This criteria seeks to reflect how much a strategy would
discourage high emitting RWC appliances or poor RWC practices.
Sat1Level10n
Fully
well
Possible
Points
S-10
7-8
Conditions for Satisfying This Level
Effectively eliminate all worst appliances
or practices.
Significantly discourages a substantial
percentage of poor RWC appliances or
practices.
Moderately 4-6 Discourages some poor appliances or
practices.
Poorly 1-3 Little effect.
None -0- Encourages (if inadvertently) poorer RWC
appliances or practices; or, no effect
at all.
-------
Strategics f-1 end ,?£ wrnch restrict consumer choices to
certified stoves/furnaces ;,;ost strongly discourage continued
installation of "dirtier" burning units. The subsidy in Strategy
$2 enhances this effect. RaD to improve RWC appliances/practices
works directly to change poorer equipment/techniques by obtaining
needec knowledge (Strategy ^13;. Periodic inspection (Strategy
?15/ would detect poorly operating burning units and require
iTiuintenance - the only strategy directly enforcing good RWC
practices in the hot.ie. Strategy #14 discourages all RWC by
restricting wood supply, and by encouraging conventional fuel
use. Strategy ??9 discourages larger stoves which tend to have
higher emissions.
Labeling strategies (£3, #5) do not limit consumer choices
to the cleaner burning units, although a tax credit (#4) would
help achieve this result. Moisture control (#8) tends to dis-
courage inadequate seasoning of firewood, but is voluntary.
Likewise, encouraging larger firewood piece size in stoves (fire-
places not affected) is too discretionary to have a major dis-
couraging influence on poorer practices. Episode controls (#12)
are voluntary, and emphasize temporary cessation of RWC rather
than improving one's RWC equipment, although public education
on proper RWC methods helps discourage poor ones. Underfire
air sources affect only small fraction of RWC situations (new
fireplaces). Ueatherization has relatively little effect on
worst practices or units.
F. WANT #6: Minimize Consumer Cost
This criteria is to reflect how well a strategy would
minimize any RWC costs (fuel, equipment, O&M, pass through costs
from manufacturer or retailer, etc.). Such costs also may be
offset by subsidies in some strategies.
L-10
-------
'! sf action rossiDle - ,. ,- T, , ,
, -. . , .'.,:,:. i ,:'-; s r,r ^ar.; sty m:. 1ms Level
Level PIT. nts
Fully 9-10 No added costs for consumers; or reduced
costs.
..ell 7-u Low costs to affected RWC households.
lOderately 4-5 Significant costs tc only a fev: R'.iC
households.
Poorly 1-3 Significant costs to a significant number
of RbC households.
-C- Substantial added costs for RHC house-
no! ds (SlOOOs).
Encouraging larger firewood piece size (Strategy #10) scores
10 because it has no dollar or inconvenience costs to consumers
(costs of public information desemination are very small, tax
payer costs). Downsizing stoves (#9) reduces average stove costs.
Encouraging alternative fuels (#14) by lowering conventional
fuel costs provides lower cost alternative for RWC households
which face higher firewood costs due to restricting firewood
supplies. Moisture control (#8) and episode controls (#12) are
cheap. Labeling strategies (#3, #5) preserve options to buy
cheaper units; subsidy option (#4) potentially reduces consumer
costs. Limited weatherization (#7) is less costly than the more
widely applicable case (#6).
Limiting consumer choice to certified stoves (#1, #2) should
increase average stove costs, perhaps significantly.
G. WANT #7: Use Proven Technology
This criteria reflects whether a strategy's technology
is proven for this application; has low O&M problems; needs no
R&D.
1-11
-------
Sati sfaction
Level
Fully
well
Moderately
Possible
Points
9-10
7-8
4-6
Conditions for Satisfying
This Level
All technology required is fully proven,
In some application or use.
Technology fully proven,
different use.
Technology assumed sound,
but only for 5
but untested;
or not applicable because no technology
is involved.
Poorly 1-3 Possible problems with technology
anticipated.
''one -0- Technology problems likely; risky.
Weatherization (#6, #7) and conventional fuel use (#14)
are fully proven technologies. Downsizing stoves U9) and
encouraging larger firewood piece size (#10) require no new .tech-
nology. Testing/labeling strategies (#3, #5) do not limit allow-
able stove emissions, and so will not necessarily favor newer
(less proven) technology, as will Strategies #1 and #2. Moisture
control (#8) and episode controls (#12) do not rely on any tech-
nology. Underfire air (#11) technology is assumed sound but
not well documented by research to date. R&D (#13) improves
proven technology over time, as well as finds new technology.
H. WANT #8: Minimize Circumvention
This criteria is to reflect ease of non-compliance (or
non-response) to strategy's objectives.
[-12
-------
atisfaction Possible Conditions for Satisfying This Level
Level Points
Fully 9-10 No circumvention occurs
Hell 7-8 Difficult to circumvent, so little occurs;
perhaps due to good enforcement.
loderately 4-6 «ot too easily circumvented; little
incentive to do so.
Poorly 1-3 Relatively easy to circumvent, but
probability not high.
-0- Easily circumvented; high probability
of occurrence.
For Testing strategies (#1 - #4) scores are proportional
to assumed percent coverage - e.g., 90% for Strategy #2. The
"carrot and stick" of Strategy #2 ranked highest because of the
control of stove sales coupled with the incentive to purchase
the certified units. Tax credit costs were not considered a major
problem because the State of Oregon has had pollution control
tax credits for industry for years. Oregon could reallocate
.some of these pollution control expenditures to RWC, which has
surpassed industry in total particulate emissions in Portland.
Weatherization of all households (#6), enforced through utility
service change, was considered much more enforceable than weather-
ization limited to households purchasing new stoves (#7) enforced
via building codes and installation permits. Building permits
were considered much easier to circumvent. The inclination to
circumvent would be higher for the homes singled out for this
requirement. Strategy #14 with its subsidies for conventional
fuels and firewood restrictions would encourage the use of dif-
ferent fuels. Piece size (#10) produces no incentive to cir-
cumvent, nor do underfire air (#11) or R&D (#13). Other strat-
»
egies have one or more elements that are fairly easily circum-
vented.
-------
I. >.A,;T /r9: i-'.axiiviize Agency Feasibility
This criteria reflects strategy's likelihood of minimizing
major agency problems such as costs, lack of authority, or
political opposition.
' ^J L c Conditions for Satisfying This Level
Fully y-10 "Cheap" and easy to implement, and to
document results; affected parties
cooperate.
..ell 7-C Only minor adtiiinistrative problems.
iioderately 4-G ;iinor problems certain; ir.ajor problems
possible but thought to be avoidable.
Poorly 1-3 At least one major administrative problem
(cost, authority, politics) likely' to
block or postpone implementation.
iione -0- Too difficult (or expensive) to implement,
or to obtain needed legal authority; and
strong political opposition.
Highest scores (9) go to encouraging larger piece size
(Strategy #10) because it is so easy to implement, and Strategy
#5 because the private sector implements it. Underfire fireplace
air (#11) and moisture control (#8) present agencies with little
work, few problems. Stove sizing (#9) and episode controls (#12)
offer only minor administrative problems. Somewhat greater
problems occur in implementing R&3 (funding problems), and
mandatory testing/labeling (#3, #4). Inspection-of RWC households
(#15) could face major public opposition and in Oregon legal
prohibition against regulating residential heating as an air
pollution source. Major problems with Strategy #14 include
limiting access of public to public lands, and possibly political
flak for subsidizing conventional fuels.
-------
J. '..,\;;T ?? 10: Encouraje Innovative Techno logy
This criteria reflects strategy's likelihood of using,
or fostering the development of innovative technological
approaches.
Satisfaction PcssiLle .. . , ".-,- -, , T
nr,..-, ^onduions for ^at i sf^ ,<>..., \ \ ; s Level
Fully 9-10 F'.ajor commitment to innovation; or
encourages it through subsidy.
..ell 7-8 Significantly encourages innovation.
Moderately 4-6 liildly encourages innovation.
Poorly 1-3 Doesn't discourage innovation, but not
likely to have much effect.
hone -0- Discourages innovation; favors conservative
approaches.
R&D (Strategy #13) easily scores 10. Requiring (#7, #9)
and subsidizing with tax credits (#9), the purchase of cleaner
burning stoves, is a major encouragement of innovation in stove
design. Except for subsizing cleaner labeled stoves (#4), all
other strategies only mildly encourage innovation, if at all.
K. WANT #11: Minimize Free Market Interference
This criteria reflects strategy's non-interference in free
market supply, demand, or pricing of goods. Use of market
mechanisms, or incentives/disincentives to regulate RWC is scored
low unless favored by private sector - e.g., voluntary regulation
by Trade Association. Promotion of better educated consumer
choice, scores high (enhances market).
-------
jatlSTuCtiOn r'USS'ible r * <- c r ^ < TI i
, T n - Conditions for Satisryinc Tins Leve
Lc/'Gi POT TIL:, j 3
Fully 9-10' iio interference with supply/demand or
prices related to RWC.
..ell 7-o Strongly promotes better consumer choice.
.oc'erately 4-o moderately enhances consumer infon.iat ion,
but may not affect consumer behavior very
much.
Poorly 1-3 Little or no effect on price or consumer
choice.
ione -J- Direct interference with price, or supply/
demand and which is not accepted/sanctioned
by private sector.
Encouraging larger firewood piece size (Strategy #10) has
no interference with market forces. Encouraging downsizing of
stoves (#9) places -larger units at some disadvantage, but this
is far from direct interference. The testing/labeling strategy
(#5) is implemented by the private sector itself. R&D (#13),
and labeling without limiting which stoves can be sold (#3, #4)
enhance market activity by promoting better informed consumer
choice. Tax credit subsidies (#2, #4) directly interfere with
inarket prices. Mandatory weatherization indirectly interferes
by tying up significant funds that could be spent on other projects
and by creating a market for weatherization which competes with
the conventional fuel market. Encouraging conventional fuels
through lower rates and restricting wood supply, doubly inter-
feres as well as benefiting industrial users of wood residues.
L. L'AKT #12: Promote Conservation and Renewable Resources
This criteria reflects strategy's likelihood to directly
or indirectly encourage conservation of energy, or use of renew-
able resources (except wood for RWC).
E-15
-------
Satisfaction Pos^le Conditions for Satisfym., IMS Level
LcVCi ("'01i.CS
t-ully S-1C Strongly promotes conservation and renew-
able resources.
Significantly encourages conservation an:
renev/able resources.
, .ocerutely encourages cur.servc.c. jn .,rr'.
renewable resources.
?ocri> 1-3 Little or no effect.
..me -C- Discourages conservation or encourages
use of conventional fuels ;oil, 3as,
electricity).
..eatherization (#6, $1} directly encourages conservation
of energy, but much less so In the case of limited mandatory
weatherization (£7). Aside from R&D, which can strive to develop
RUC appliances/practices which conserve energy, all other
strategies have little or no effect.
III. RISK FACTORS
Table E2 summarizes the WANT criteria scores and the preliminary
ranking they provide among the fifteen final control strategies.
Table E2 also shows the ris'k factor scores assigned to represent major
potential adverse consequences of implementing a strategy. These adverse
consequences scores are summarized in Figure El and discussed in this
section. Risk factors were discussed in Section III D of the text.
The adverse consequences listed in Figure El were those considered
rnost likely to block or limit the effectiveness of a strategy. In
many cases, the risk factors represent the possible failure of key
assumptions to coine true, which would undermine the strategy in sig-
nificant ways - e.g., the failure of the RWC industry to commercialize
-------
I:.vlci,.ci,t",nJ Final fifteen r.'.-C Control 5trate<^:_s
tr^ coesn'L Provice a stove which 3
er.iits £5 ^,/kc, for<_$1200.
LeCjdl autiioriiy to prohibit sales not 5
obtai tiaole.
Public opposition to freedom of choici. 3
in stove urcLasoj.
Ctrate:,y ,fZ: '.Tesiiii'^/Ld
- Inability "Co clta-.n lecal authority to 4 1C
require testinc, and prohibit sales of
nun-labeleo units.
ProOubility of Occurrence ', 1 to ICj
~>'^r ~\ OuSiVriS of it jjc.CC , 1 tO 1C.1
;,* -ujtc
- S.
o t r i. t _ ^. ; 1 : . . ji) L i Uj/ Certi f "scat! on;
x ; i v, I. S *-Tj ' <:,j' ; i. I, !' . iCS C' *1>. :V
- !tl , \ <.. _, . ".. <_; : L_ , .
" ' !-' -< i - i , v ^ - ; - ' - -' - j -> - 40
rrecuo;., of c,,o,:;i. <. ,< stove
,-iUrdlCSii .
ifiaoi i i \.j i'j o^Luiii i._.jul Sutnontj 5 ]0 jj
to pronibit Scles/ir;StQ] 1 atior, of non- , ,
cert-'ifioc: units iu'. ] ..st i ;: 'J)\?'jor:
'.-.isere OkS ^3^.2^(5, exempts rssidctiticl
space hecit":!;; Trotr. ri.-j jl at ion; .
Stratuby f/2: ylestin-j/Certificat ion, tax credit)
Lack of funus for subsidy (General Fund 5 10 j^
strapped) industry oppose tax credit shift?
r-is
-------
-T , . -T *, _ t
r 11. 'v. i, iZ -I , L. 1.1: L . ,
ial Adverse Consequences Probability Seriousness i\isk Factor
of Implementation of Occurrence cf Impact (? x S)
.;....' i ..'_,, _o/'. crv-'.i i c,
v L \^ /'
LL-' "I, -T - , j ,-'-
/ u J - I I I C ^ 3 I -» vJ L . - x.' [ i u j
^ " ' > *" *~ J ) ' J '"
.- I i ^ ,v I \j I ) I L- i '- o w1 t <" ->
i n^/Rat'i ng, Ly Industry,
i; - f'ro^cioi 1 ity of Occurrence \1 to 10)
cS / jloxl'j = unavc i >Ja.. 1 c disaster
£-19
Strategy £j: u.'eatherization, all households)
- Public acccvtarice i Voter approval; of 5 ^ ' 40
uandatcry weatlierizotion may not oe obtained.
- /.(jc^uate fiiianci ng -nay not be available. 3 10 30
70
Strategy f:7: (..'eatherization, only
certain households)
- Public acceptance of limited inandatory 5 ii 25
,',eatherization could be much worse but
affected group is smaller.
- Adequate attractive financing may not 1 10 10
be available. 3r
Strategy irO: (i'ioisture Control)
- Limited research to date n;eans estimated 4 G 2<-i
benefits inay not be realizable as estimated.
-------
;uienlic,l /.dvcrse Consequences
of Ii..H']'3:;.eiitation
Probability Seriousness Risk Factor
of Occurrence of Impact (P x S)
(P) (S)
.Sizing)
0 j H J V i Z. S i . . c,_y
.-"C:l . lirt-fiS c S t'i I..C. L-'-iU
i i 0 v. 0 c T c (.'' I I Z G 0 I c c; S
Limiceu rLsaarcf means estii,:atec
jcnef.Ls , ay iiot i^c realizable as
esti .at-jC.
tratcjj' ;;11: ^r~i rep lace iinuerf'ire Air)
L1,-.riteu research (one test) n.eans estimated 5
Deneflts ,,;ay not be realizable as estimated.
40
.^y ;;1Z: jEplsode Controls;
- Legal authority for mandatory curtail -
nient r.,ay not .aateriallze, lihiitinc,
a;., to voluntary approach.
10
50
Strategy £13: ^Research 6 Developiiient)
- none
-u-
Strate^y ,,r!4: (encouraging Alternative Fuels)
- Public acceptance of linn ting of wood
supply unlikely.
DO
Strategy -/15: (Inspections)
- Lec,al sutiiorit^ for inspections i.iay not
,:.ctt. r ', al ' ze (especially "in Oregon]-.
10
70
E-20
-------
a stcvc whicii eiTiits 5 g/kg and costs $1200.00, by about 1934. This
assumption underlies Strategies £1 - -'4. If it die not come true,
Strategies #1 and #2 v/oulcJ be affected i.iost because they limit consumer
choice to stoves v/hich emit
-------
her each strategy, the total points assigned for risK, factors
in Figure El was compared in Table E2 with the total U'AiiT criteria
scores. These two scores were not substracted, but their relative
magnitudes were compared to consider whether the preliminary ranking
based on WANT criteria scores should be altered due to potential adverse
consequences of implementing any strategy.
The two top rankec strategies U'l and ,?2) also had the two highest
adverse consequences scores; and the fourth ranked strategy iiad the
next highest risk factor. The ii.ajor risk factors involved possible
problems in obtaining legal authority to require testing and to restrict
commercial sale of non-certified or non-labeled stoves. In depth
analysis of barriers to enactment of such legal authority was beyond
trie scope of this report.
However, precedent exists for such legal authority in control
programs implemented in Britain, Mew Zealand, and West Germany (see
Section II A, B, and C); and in the program adopted in Medford, Oregon
(see Section II E), which urged development of a state'certification/
testing program. Precedent also exists for state tax credits for
32
industrial pollution controls - e.g., in Oregon. For Portland,
Oregon, RWC particulate emissions are estimated to equal or surpass
industrial particulate emissions (in tons/year), and are potentially
i;:ore hazardous to public health since the emissions are released in
sensitive population areas. Thus, in Oregon at least, a strong argu-
ment can be made for simply reallocating pollution control tax credits
frosn industrial to RWC controls.
Thus, because the potential emissions reductions are significantly
greater for Strategies #1 and #2, and major risk factors seem surmount-
able, no change was made in the preliminary ranking of these top rated
strategies.
No compelling reasons were found to alter the other rankings
either, so the initial WANT criteria ranking became the final ranking
also. Several observations about the relative rankings seem noteworthy,
however. For example, R&D (Strategy #3) ranked high (5th) and had
-------
no acverse consequences. Its benefits are speculative ay nature, how-
ever, and f;iu funding "is scarce under present economic conaitions.
Several strategies which rank fairly nigh - e.g., promoting larger
firewood piece size (#10) and smaller stoves (#9) - did so in part
because they don't present many problems, but they are based on very
thin research results. These strategy approacaes are prnr.e caiicidat = s
for future restore!..
-------
SelzCteu Costs arid uenefils of Final i;..C Control Strategies
This appendix estihiates selected dollar costs assumed to be
associated with implementation of fourteen of the fifteen final Rv.'C
Cor.trol Strategies selected in Section VI for final evaluation and
ranking. It also describes selectee jetiefits in narrative terns for
each strategy, uo dollar costs ,vere estimated for Strategy f/H, v.'hich
calico for encouraging fuel alternatives co iV,;C.
- -r - . T '" r* V T ' *~' ' / n *~ n I *~ *~ *~ T <~ ~!> * ~ r I.^T i.~ T - - -i r* °> 'o '^T~nTTr~T'~
j I ;<(-. Ic^Y rl: i'!L.-i/I\t.rLM^Li iLn I j ! ^'. c_ ;.Jji ^c ILJICJ /-.i,L/ LCJ\ I 11ri c.
TO EMIT LESS TKA;> -j G TSP/;
-------
..Ljui.it ;.2,ouu per test, Oetenrrination of efficiency by
'.,:e stack loss i.iethud also v:as incli.ceo ;, ith'ii, cr.ese costs.
If an emissions rating program were established, some range
of operating conditions would need to be tested rather
tiian one single burn rate, since emission factors generally
vary significantly with burn rate. Testing four different
burn rates probably would bo sufficient to characterize
emissions over a ran ye of conditions, ,/hile still dllovnncj
any serious test procedure error to be identified. Without
economies of scale, four separate tests v/ould thus be
estimated to cost about SIC.UCO. ',. ith the econo;;.". er. of
repetitive testing on Multiple stoves, c cost of about $5,000-
v7,5CO seems a'reasonable estimate for testing particulate
emissions at four different burn rates by this method.
9
2. Efficiency Testing by Calorimeter Room and Stack Loss Method
She!ton Energy Research of Sante Fe, New Mexico cur-
rently tests stove efficiency by this method for about
45
$5,400 per stove. This includes six different tests
at low to high burn rates to characterize performance over
the range of operating conditions. Combustion efficiency
determination is included in this procedure. This also
would provide other options for structuring certification
requirements. For example, rather than setting an emis-
sion limit of 5 g/kg, some minimum combustion efficiency
could be required with the certification program essentially
the same in all other respects.
-------
o. JritiGt! electrostatic Preci^itator iiethoc
British law requires stoves to >.,eet certain ei;nssion
liir.its in order to be installed in Smoke Control
Areas. ' Testing is conducted by the British Coal
board (NC3) using an electrostatic precipitator method. ' 1
Using this net hod the i'iCB estimates the costs of testing
one stove to be $2,400, which includes 5 tests at eecli
of three burning rates (low, medium, and high). ',,'hile
this test is not necessarily applicable to wood stoves
because of its questionable capture efficiency for vela-
tiles, it does illustrate a comprehensive testing program
,n octual operation.
4. liew Method-Combustion Efficiency Measurement Using Catalysts
These authors conclude that one of the least expen-
sive test methods likely to be developed and commercialized
involves the use of catalysts to determine an emission
factor in the form of grams of unburned carbon per kg wood.
This method would involve complete combustion of some known
fraction of the stack gas via a catalyst with known amounts
of oxygen supplied to ensure complete combustion. Measure-
ment of CCL concentrations before and behind the catalyst,
stack flow measurements, and determination of the amount
of wood burned also would be required. Both CO and par-
ti cul ate emissions are of concern, and this method would
sidestep issues of how much.of the carbon was in one form
45
or the other. Shelton estimates that costs for conducting
such a test for four different burn rates might ultimately
be reduced to about $2,000.
5. Single Estimate of Model Testing Costs
The arithmetic average of these four possible evalua-
tion procedures (each including multiple tests) is $4,400
-------
[<2u'_6 + 2CGC + j^GC T 7500;/4 = 4375]. Tnls value Is
selected as the best sirujle estimate of costs per model
testec for emissions.
Test Procedure Development
In order to document the acceptability and valioit'-1
of ',,'hatever emissions testing Method is selected, it "is
arbitrarily assumed that about $50,000 in research contracts
or expenses would be required. This, for example, would
allow four stoves to be tested five times by the Oregon
ilethod 7 procedures (t?$2,500 per test).
Adiiiini strati ve Costs
If it is assumed that about 30 new stove models would
be tested each year, at an estimated $4,400 cost per stove
tested, this would result in $130,000/year allocated for
testing costs. If it is assumed this program would require
two professionals and one half-time secretarial position
for testing and report-writing activities at a $30,000/year
average loaded rate, these labor expenses would total
$75,000 per year.
This would leave a remainder of $55,000 per year
for rent ($15,000/year), wood acquisition and standardiza-
tion costs ($5,000/year), printing ($5,000/year) and
amortized equipment purchase ($30,000/year), which appears
reasonable.
Allocation of one-half professional person for
enforcement activities and one-half professional person
for education and public relations activities would add
about $30,000/year for annualized costs of $160,000/year.
Charging manufacturers $1,000 each to test/certify each
stove, could recoup $30,000 under these assumptions,
reducing total administrative costs to $130,000.
-t
-------
Per wtovc Lusts
, ,L,.,i ii i strati ve 'costs of 'ciris program per stove ore
estiii.atec for jurisdictions v;ith annual stove sales of
5,000 to 10,000 and 20,000 in this section. After the
research expenditure of $50,000 to establish and verify
tl'.e test procedures, the $130,000 annual operating expenses
,,culc result in costs 10 the rcvarniiient per stove solJ
of .-^o, -1^, jf $O.D^ fi-r tiiese three cases. The costs
of attc-cii !ii;; e laL>el ,/iiicn specifies emission rates and/or
efficiency is estimates at $5.00 per stove (labor end ,,;6ni,-
facturin:, costs/, jr !*>_, udi, iini strati ve costs per stove
to $31, vlo, anc ^12 respectively. This $5.00 labeling
cost ,vas assutiiec to apply to Strategies #1 - /75. Since
Strategy ?1 is assumed to assume only that 60% of stoves
purchased are certified, the administrative costs per
"affected" stove are $52, $30, and $20 respectively.
Research and tax credit costs are not included in these
per stove costs.
3. Benefits
Analysis in Section V A 1 estimates the emission reduction
attributable to this strategy as 8% by 1990 and 30% by 2000.
Thus, the emissions reduction benefits accumulate over time sig-
nificantly, as more and more new and/or replacement burning units
are installed, 50% of which are assumed to be the cleaner,
certified types.
II. STRATEGY #2: NEK/REPLACEMENT STOVES MUST BE TESTED AND CERTIFIED
TO EMIT LESS THAN 5 G TSP/KG WOOD BEFORE SALE OR
INSTALLATION IS ALLOWED; PLUS $400/STOVE TAX CREDIT
Strategy #2 would employ the same staff and facilities, and is
assumed to have the same base costs as Strategy #1 ($130,000 per year
adininistrative costs, plus $50,000 one-time research costs to develop
-------
, Hlus tax crc-c;.;, cci.cs. Tax crec.it costs (tax revenues
;ere estn.iattu cssui.iUKj a percent coverage of DO/, for Strategy
-:Z - 'i.e., that 90% of new units woula be certified and hence eligible
for the tax credit.' For annual sales of 5,000, 10,000, and 20,000
units, this results in annual tax credit costs of $1.0 - $7.2 nnllion.
Additional aduiini strative costs to a
-------
to result in 3% emission reduction benefit by 1990 and a 11%
v2,,L-M i by 2'JGG.
GY -*: TESTING AS JASIS FOR MANDATORY LABELING PRIOR T(J SALES, PLUS
340G/STOVE TAX CREDIT
., r . TI t'.al research, and annual au.nrn strat", ye ;^_,f s
for t.'vis ,jrojra;,< are essentially the same as for Strategy "2.
nc,;ever, costs ,jer ceriifiec stove purchased are 2.25 tk.^es as
,:"i.jn, S''iC2 jtrate-jj- "4 is assuivied to effect only 40'. of the
bcoves ^jrciidseL jer yaar versus the 90% for Strategy ;-2. Ihis
also affects the tax credit costs for the three sales volumes'
cunslcerec: i5,GuO, 10,000, and 20,000 sale per year), because
only 40';t of the units purchased would be eligible for tax credits.
This results in annual tax credit costs of $0.8 - $3.2 million.
C. Benefits
iiased on analysis presented in Section V A 1 and Appendix
Li, this strategy is assumed to result in an 5% emission reduction
benefit by 1990 arid a 21% benefit by 2000.
STRATEGY ,-5: TESTING/RATING BY RWC INDUSTRY TRADE ASSOCIATION
A. Costs
This strategy's costs would be essentially the same as
for Strategy #3 (#1), but with the RWC industry -instead of govern-
ment implementing it. A significant difference in distribution
or pass through of costs to the public would exist, however.
If industry passed on to the consumer the per-stove admin-
istrative costs identified for Strategy #3 ($12-31 per unit),
"-7
-------
LIVI. ;,'urc,liUbers of new wood sieves would pay for ttTis strategy.
IA.C'' _ ui'o'oL ^ i Ji i""l ~ ."S , -jO V9rni.,dri t tjdyS c. I I COotb >;iiiCil C.r'J
i.rii.s effectively distributee over all taxpayers. Averse tax-
payer costs would range from a few pennies per year for Strategies
rl and r'3 to $5-10 or more per year for Strategy -?2 involving
;mi r.ax credit costs. However, since total particulute emissions
from ;t,,C in areas like Portland, Oregon rival or surpass total
_,. iSiior.s fro;.: all other industry , states {like Oregon) which
otter substantial industrial tax credits for pollution abetenent,
,;,ciy ,-ant to adjust their tex credit prograia to accor,;n,cdate the
;.'.,C source.
STUATIbY ,-6: JEATHERIZATION OF ALL HOUSEHOLDS I.'! Ah AREA
A. Costs
Pacific Power and Light estimates that weat'nerization of
a typical household in the Portland metropolitan area costs about
46
vl,400 to $1,500 per household. This includes such activities
as roof and floor insulation, addition of storn; windows, and
caulking and weather stripping. For an area in which 60% of
households can be characterized as "poorly weatherized" this
results in average weatherization costs of about $900 for each
household in a metropolitan area ($1,500 * .6 = $900). For metro-
politan areas with 100,000 or 300,000 households, this would
require investment of $90 r.iillion or $270 million.
Estimated adi.iinistrative costs for a mandatory weatheriza-
tion progran; assumed 5,000 to 20,000 households weatherized per
year. Assuming administrative costs of $30.CO/h'cusehold, affords
annual administrative costs of $150,000 - $500,000. Assuming
weatherization of poorly weatherized RWC households is accom-
plished in 10 years, starting in 19C5, the full 7% emissions
reduction would be achieved by 19S5. For Strategy #7 (weather-
ization of households installing new/replacement stoves), a
-------
Cc.r average stove; 1'ife vas assu.ec JL- aiuu.tJ rc-,jlacer,,erit
cot.'j for existing stoves;. Tins also results in full .^ether-
ization benefits within 10 years. Assuming 1U.-C households are
10% of all households, annual administrative costs could range
fro'.. 320,000 - 580,000 per year.
In the short-term, weatherization of GC/> of an area's house-
holds such that heating requirements are reduced by 40?c is
-istiuatec to reduce Rl.C emissions by 1995 by about 7% (see Section V
j 1,. riowever, most weatherization programs incorporate only
cost-effective conservation actions, with a 5 year or less pay-
DUCK. Thus it can be arguec that the v/eatheri zation proyrai,,s
"pay for themselves" in ultimate fuel savings, with emission
reouction a side benefit.
VII. STRATEGY #7: MANDATORY WEATHERIZATION ONLY FOR HOUSEHOLDS
INSTALLING IJEU WOOD STOVES/FURNACES
A. Costs
For an area with 100,000 households in which either 10%
or 20% of households are projected to buy new or replacement
stoves between 19C5 and 2000, weatherization costs over that
time period at $1,500 per household would equal $15 Million or
$30 million.
o. benefits
If all households were to cooperate with this strategy
and not circumvent the requirements by installing stoves without
"permits", the emission reduction benefits would equal those
i7%) of Strategy #6, but with less weatherization investment
-------
costs. However, more circumvention would probably occur; 30% more
was assumed by 1992 (3.5%) reducing emissions reduction benefits
by this amount to 5% by 1995. The extent of circumvention would
depend on the financial burden involved, which could be mitigated by
attractive financing terms (no or low interest loans), and
whether the requirement is accepted as equitable.
liOISTURE CONTROL
Aratt^ieS c, i, and 10 are all public education 3tr
...ui coi-li- all be incorporated within a comprehensive public eciuca-
iL.-.".':ejy. Costs presented in this section can b. r.;,ti3iuered to
cover Uirate^ies o, 9, and 10 m combination. It also was assumed
tliut luplementation of any one strategy would cost half as much
;$45,OCO) as implementing all three ($90,000).
In order to achieve the emission reduction benefits cited for
these strategies in Section V I 2, it is assumed that the following
administrative and materials costs would be incurred.
Agency Information Officer
Grie full-time professional ($30,000) could communicate
the desired changes in operating practices to the general public
by making ICO talks/presentations per year, and managing the
v.ievelopii.ent of media materials.
Television and Radio Spots
Once prepared, video and radio spots likely would receive
free airtime for presentation to the general public, as did six
video spots on wood heating practices in 1981 in Oregon. The
Uorthwest Power Council funded the development of six low-budget,
still-picture video spots on wood heating practices in 1981.
It is assumed that a similar $50,000 expenditure could produce
three or four higher quality spots on optimum operating practices
to reduce emissions, and that these spots would receive free
air-t"i,!ie -
-------
r.rt',;crk, typesett; r..j5 anil Dinting costs are estimated
at $1,DGC fur production of Zo,ClG copies of a three-fold/paye
brochure. Producing ICu.CCC copies per year would thus be
estimated to cost less than ~o,OuG/year.
_,. ocnef i Ls
Educational proyra;:iS to promote the better drying of wood
were estimated to be able to reuuce emissions by 6.2% in
Section V B 2.
IX. STRATEGY .-*3: STOVE SIZI..C
A. Costs
Costs for an educational program on this subject were dis-
cussed under Strategy #B above.
o. Benefits
Educational programs to promote stove "downsizing" were
estimated (Section V C 1) to be able to reduce emissions by 7%
by 1990 and 10-11% by 20CO.
X. STRATEGY #10: ENCOURAGING LARGER PIECE SIZE
A. Costs
Costs for an educational program on this subject were dis-
cussed under Strategy #8 above.
3. Benefits
Educational programs to encourage the use of larger pieces
of wood were estimated to be able to reduce emissions by 11.5?;
in Section V C 2.
-------
;.i. -",,.,i_:': -ii: \:vui:.: FIKZPL.^ZS TO ,-;/-,VE A.;. U;;JE::FI:, or ArJ,,uUL' rer ton. This compares to one recent
estimate of control costs for industrial particulate sources
33
of about 310,000 per ton. On an annual basis, for an area
in which 1000 to 3000 new fireplaces were installed, adding under-
fire air systems to these units would result in incremental costs
of $100,000 to $300,000 per year.
3. Benefits
Based on the analysis in Appendix D 1 c this strategy is
assumed to reduce year 2000 emissions by 2%. Reductions by 1990
would be estimated to be less than half of that, or about 1%.
XII. STRATEGY =12: EPISODE COiJTROLS
A. Costs
Establishing a voluntary episode control program under
,-i'hich wood burning households are requested not to burn wood
(unless it is the sole heat source) should cost about $25,000
in initial investment and $G,000 in annual operating costs.
These costs estimates are derived.largely from experience gained
22
with the episode control program in operation in liissoula, HT.
-------
Initial Investment Costs Estimated at $25,000
- Automatic Particle ;-'.cr,itor, for real time particulate monitor-
ing costs about $15,000.
- The Missoula Air Pollution Control Agency spent $13,000 for
peripheral computer equipment to provide access to the state
agency's air quality computer. This equipment provided other
benefits such as word processing, printing, and model liny cap-
ability, so costs allocable to the cata acquisition system are
arbitrarily assumed to be $10,000.
Annual Operating Costs Estimated at $0.000
- 30% of one professional's time is required over 5 winter months
to coordinate the I'.issoula system. Based on an assumed loaded
salary cost of $30,000 per year, this costs $3,700 ($30,000
X 5/12 X .3 = $3,700).
- Equipment maintenance/repair costs estimated at 10% of invest-
ment cost per year or $2,500.
- Phone system with recorded messages on air quality status costs
are about $1,150 per year.
- Miscellaneous costs of $650/year would result in total annual
operating costs of $3,000.
B. Benefits
The chief benefit of this strategy is emissions reductions
on worst air quality days, estimated at 33% for RWC emissions
on worst air quality days in Section V B 3.
XIII. STRATEGY #13: RESEARCH AND DEVELOPMENT OF IMPROVED RWC
APPLIANCES OR PRACTICES
A. Costs
Costs for this broad category of research and development
-------
work cepend clearly on the level of research undertaken and the
cegree of outside support. Possible costs for three of ttie more
promising research areas are discussed below.
Private/Academic Research Contracts
$100,000 per year could be allocated t~ cupport the develop-
ment of in,proved R'.JC appliances and practices, in a program
similar to the "appropriate technology" support grants which
soi.ie state governments fund, by limiting single grants to $10,000
and establishing a format for vrant competition, new and innova-
tive wooc! burning technology improvements could be encouraged.
Government Funceci Emissions Test Facility
Testing prograi.i cost estimates were generated in the dis-
cussion of costs for Strategy £1. The annual operating costs
for conducting tests of 30 burning units per year at about four
operating conditions per unit, were estimated at $130,000 per
year, including test equipment amortization. Uith a research
and development focus, the program could include 15 device tests
and 60 tests (15 x 4) to compare the benefits of alternate
operating practices.
Awards for Development of Low emitting Woodburning Units ami
Simplified Emission Tesfs
Two $50,000 awards could be offered for the development
of 1) the first woodburning unit which emits less than 1 g/kg
of particulate concurrent with an overall energy efficiency of
50« or greater and 2) a simplified emissions measurement tech-
*
nique with costs per burn cycle test of less than $200.
3. Benefits
No potential emissions reduction benefits could be estimated
for this strategy because its results are by nature too uncertain.
-------
However, ,,'ith tcoquate funding R&D could be extremely valuable
in prorr.otinc; the advancements which are most needed in controlling
R'.JC emissions - e.g., inexpensive, standardized emissions test
methods/equipment, and better quantitative data on emissions
under various burning conditions.
XIV. STRATEGY :n-;: ^iCUUuACIi-G CONVENTIONAL AND ALTERNATE FUELS
A. Costs
,'iO costs were estimated for this strategy because the
activities involved could not be well enough defined. The
institutions involved already have programs which would be
involved. Estimating their incremental costs to do what this
strategy calls for would be very difficult.
B. Benefits
Likewise, no emissions reduction benefits could be esti-
mated. Benefits would include holding down utility costs of
lower income people (lifeline rates), and promotion of renewable
energy sources (solar). However, provisions for restricting
wood supply would not be popular, benefiting only those who would
become the recipients of this bioir.ass for alternative uses.
XV. STRATEGY #15: PERIODIC INSPECTION OF RWC EQUIPMENT
A. Costs
4
For an inspector employed six months per year at a loaded
cost of 315,000, and an inspection rate of six burning units
per day, labor costs would be about $20 per inspection ($15,0007
(b units/day x!25 clays) = $20/unit inspection). An assumed
equipment and training cost of $3,75C/year would increase costs
-------
per unit inspection to about $25 ($3,750/750 units per winter
= $5). For an area in which 50,000 to 100,000 units were
inspected per year, costs in the $.75 to $1.5 million range would
result.
T..c ...ajor oenefit which would be achieved by such a pru3ru;,,
,,'OLild ZL in iimproved fire safety. For exa.Tiple, 32% of all sincjle
family d'./ellinc; fires in Oregon are associated with solid f^ul
ourmng ec^uipr.ient. J If an inspection program were to reduce
t'.iat 33, to 15^ then an 1C« reduction in total single fai;.". ~\j
d'/,ellinc fires would occur. This will lower claims paid by rire
insurance companies. If these savings are passed onto policy-
holders, and it the average household's fire insurance cost per
year is $150, this 18% benefit would equal a $27 ($150 x .18
= $27) savings per household per year. This value is slightly
in excess ot the estimated annual costs of an inspection proyrau.
For an area in which 50,000 to 100,000 units were inspected per
year, benefits in the $.75 to $1.5 million range would result.
------- |