United States
Environmental Protection
Agency
UTTICC OT
Research and Development
Washington, D.C. 20460
EPA 600/7-76-014
OCTOBER 1976
POTENTIAL ENVIRONMENTAL IMPACTS OF
SOLAR HEATING AND COOLING SYSTEMS
Interagency
Energy-Environment
Research and Development
Program Report
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BAAR 9075-043-001
Contract No, 68-01-2942
Task Order No. 13
May 1976
POTENTIAL ENVIRONMENTAL IMPACTS OF
SOLAR HEATING AND COOLING SYSTEMS
For
Environmental Protection Agency
-------
OEMI-76-11
May 1976
POTENTIAL ENVIRONMENTAL IMPACTS OF
SOLAR HEATING AND COOLING SYSTEMS
by
T.J. Consroe, F.M. Glaser, R.W. Shaw, Jr,
Contract No. 68-01-2942
Task Order No. 13
Project Officer
G.J. D'Alessio
Office of Energy/ Minerals and Industry
Office of Research and Development
Washington, D.C. 20460
OFFICE OF ENERGY, MINERALS AND INDUSTRY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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DISCLAIMER
This report has been reviewed by the Office of Research
and Development/ 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.
XI
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PREFACE
The subject of this report is the potential environ-
mental consequences of solar energy utilization for heating
and cooling buildings. The report does not address other
solar technologies such as solar electric/direct conversion
or biomass conversion. This analysis was undertaken for
four reasons:
To provide a general but comprehensive evaluation
of the environmental tradeoffs between solar energy
and fossil fuel utilization
To encourage the development of solar energy tech-
nologies which are environmentally acceptable
To assist in the coordination of Federal agency
activities related to the environmental impacts of
solar heating and cooling systems
To develop a methodology for quantifying the poten-
tial air pollution impacts of solar energy systems
resulting from the displacement of fossil fuel com-
bustion, which can serve as a technological option
for controlling environmental pollution.
The report contains three chapters. The first chapter
identifies the areas in which both positive and negative im-
pacts are possible. The second chapter summarizes the
national research and development program directed toward
solar heating and cooling technology and describes how these
programs address environmental considerations within the con-
text of Federal agency responsibilities. The third chapter
contains a general methodology for estimating the impact on
air pollution of solar energy utilization in urban areas, and
also contains an example application of the methodology.
The identification of potential environmental effects of
solar heating and cooling systems, given in Chapter I, in-^
eludes a discussion of the increases and decreases in air,
water, and solid waste residuals associated with these sys-
tems. In addition, other impacts which are more qualitative
but no less concrete in nature, including aesthetic, social,
and consumer safety considerations, are also identified.
These qualitative impacts are addressed because, in many
iii
-------
respects, the manner in which this energy resource is tapped
differs radically from conventional energy forms, and implies
many novel problems.
The second chapter of the report contains five sections.
In the first two sections the role of R&D for solar heating
and cooling is described in the context of the national
energy R&D plan, and the responsibilities of key Federal
agencies and departments involved are identified. The third
section describes planned solar heating and cooling demon-
stration projects. Because a large number of buildings in
many geographic regions will be involved, these demonstra-
tions will probably direct attention to the first environ-
mental impacts of any magnitude associated with solar energy
applications. The fourth section summarizes EPA's role in
the development of solar technologies. The last section of
the chapter identifies the Federal agencies which are respon-
sible for analyzing and mitigating the potential environ-
mental impacts of solar systems which were discussed in
Chapter I.
The third chapter of the report describes a methodology
for assessing the impact of solar heating and cooling systems
in urban areas. Mathematical relationships are developed for
projecting fuel savings in any urban area, as a function of
the rate of acceptance of solar systems. The changes in
emissions and ambient air quality resulting from solar-induced
fuel savings are then discussed. Finally, a sample applica-
tion of the methodology and a parametric analysis of regional
emission savings using actual urban fuel use and building data
are given.
J.V
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TABLE
0 F
CONTENTS
Page
Number
PREFACE
FIGURES
TABLES
ill
viii
ix
I. POTENTIAL ENVIRONMENTAL IMPACTS OF SOLAR
HEATING AND COOLING SYSTEMS 1
1. Expected Market Penetration of Solar
Heating and Cooling Systems 2
2. Air, Water, and Solid Waste Impacts 5
(1) Reduction in Emission Due to
Reduced Fuel Combustion 8
(2) Increase in Emissions From
Production of Materials for
Solar Systems H
(3) Water Quality Impacts 16
(4) Solid Waste Disposal 16
3. Other Environmental Impacts 18
(1) Effect on Land Use Patterns 18
(2) Thermal Effects on Local
Meteorology 20
(3) Toxicity and Flammability of
Solar System Fluids and Materials 21
(4) Consumer Safety Implications 21
(5) Impact on Population Distribution 26
II. THE ROLE OF SOLAR HEATING AND COOLING IN THE
CONTEXT OF THE NATION'S OVERALL ENERGY
PROGRAM 2 9
1. The National Energy Plan 29
(1) The Goals of the National Energy
Plan 29
v
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Page
Number
(2) Technology Options Addressed in
the National Energy Plan 31
(3) The Role of Solar Heating and
Cooling in the National Energy Plan 32
2. Federal Agency Responsibilities in
the Area of Solar Heating and Cooling 33
(1) The National Plan for Developing
Solar Heating and Cooling Technology 34
(2) Federal Agency Involvement in Solar
Heating and Cooling RD&D 36
3. The Role of Federal Agencies in Major
Solar Heating and Cooling Demonstration
Projects 38
4. The Role of EPA in Solar Energy
Development 46
5. Federal Agencies Concerned With Environ-
mental Impacts of Solar Heating and
Cooling Systems 47
III. ASSESSMENT OF AIR QUALITY IMPACTS OF SOLAR
HEATING AND COOLING SYSTEMS 51
1. The Fuel Savings from Solar Heating
and Cooling Systems 52
(1) Definition of Climatic Regions
and Building Categories 53
(2) Energy Load for Each Building Type 54
(3) Potential Energy Savings Per
Building 61
(4) Potential Fuel Savings Per Building 65
(5) Number of Buildings Equipped With
Solar Systems 67
(6) Areawide Fuel Savings 72
2. Changes in Pollutant Concentrations Due
to Reduced Fuel Combustion 72
CD Area Source Emissions and Air
Quality 73
(2) Air Quality Impacts Due to Reduced
Demand for Electricity 80
vi
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Page
Number
3. Summary of the Methodology 88
4. Sample Application of the Methodology 91
(1) Energy Demand for Single Family
Residences in the Region 92
(2) Potential Energy Savings Per
Building 92
(3) Potential Fuel Savings Per Building 94
(4) Forecast of the Number of
Residences Equipped With Solar
Systems 96
(5) Areawide Residential Fuel Savings 97
(6) The Change in Areawide Emissions 100
5. Parametric Analysis of Regional
Emission Savings 102
GLOSSARY 110
vii
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INDEX OF FIGURES
Page
Number
1. Energy Supplied By Solar Heating and
Cooling Systems 3
2. Solar Equipped Buildings (Cumulative) 4
3. Energy Supplied By Solar Heating and
Cooling Systems By Building Type 6
4. Forecasts of Potential Coal Savings (If
All Solar-Induced Fuel Savings Are Coal) 12
5. Forecasts of Potential Emission Reductions
(If All Solar-Induced Fuel Savings Are Coal) 13
6. Comparison of Positive and Negative Air
Pollution Impacts (15 Year Life-Cycle Basis) 17
7. Regional Climatic Classification 54
8. Possible Impact of Solar Energy
Utilization on Load Duration Profiles 82
9. Assumed Solar Market Capture (S(T)) 99
10. Potential Emission Reductions in Baltimore
Associated with the Use of Solar Heating/
Cooling Systems in Single-Family Dwellings
in the Year 2000, Compared to Total 1972
Emissions in Baltimore 103
11. Potential Energy Savings in Hypothetical
City (Displacement of Electricity Only) 106
12. Potential Power Plant Emission Savings in
Hypothetical City in Year 2000 Resulting
From Reduced Electrical Demand Due To
Solar System Use 107
viii
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INDEX OF TABLES
Page
Number
1. Potential Environmental Impacts of Solar
Heating and Cooling Systems 7
2. Reduction in Fuel Use of 0.94 Quads* Due
to Solar Heating and Cooling Systems 10
3. Annual Criteria Emissions Associated With
Solar Heating and Cooling Systems Providing
0.018 Quads Per Year 14
4. Characteristics of Solar System Working
Fluids 22
5. Ranking of RD&D Technologies 31
6. Budget Levels for Solar Heating and Cooling
Program FY 1975 - FY 1979 36
7. Federal Agency Areas of Responsibility for
Solar Heating and Cooling (Agency Basis) 39
8. Federal Agency Areas of Responsibility for
Solar Heating and Cooling (Task Basis) 41
9. Appropriate Agency Consultation with EPA*
During Solar Energy Research and Development 48
10. Climatic Data for Sample Cities 55
11. Characteristics of Typical Buildings 56
12. Heating and Cooling Loads, B.
(106 Btu/Year) -1 58
!3. Hot Water Loads, B. 60
ix
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Page
Number
14. Energy Savings, Space Heating, and Hot
Water (F. ) (Fraction of Total Load) 63
15. Energy Savings, Space Cooling, (F . )
(Fraction of Total Load) 3m 64
16. Typical Heating/Cooling Equipment
Performance (HE) 66
17. Emission Factors for Common Residential
and Commercial Fuels 74
18. Federal Ambient Air Quality Standards* 75
19. Selected Atmospheric Dispersion Models
for Area Source Emissions 76
20. Nationwide Emission Levels (1972) 84
21. Emission Factors For Common Power Plant
Fuels (EF® ) 87
22. Typical Conversion Efficiencies For
Power Plants (CE,)* 87
23. Fuel Use Factors, FFN.,* 94
24. Projected Number of Single-Family Dwellings
to be Built to Year 2000 in Baltimore SMSA 98
25. Calculation of Area Source Emission
Reductions 100
26. Calculation of Power Plant Emission
Reductions 101
27. Estimated Electricity Savings For
Hypothetical City 108
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I. POTENTIAL ENVIRONMENTAL IMPACTS OF SOLAR
HEATING AND COOLING SYSTEMS
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I. POTENTIAL ENVIRONMENTAL IMPACTS OF SOLAR
HEATING AND COOLING SYSTEMS
Solar energy is often thought of as a source of energy
for the future that will have purely beneficial impacts upon
the environment. This is because the utilization of solar
energy will result in conservation of fossil fuels. De-
creased levels of fossil fuel combustion will result in a de-
crease in pollution released to the environment. In addition,
conservation of domestic fossil fuels by solar energy will re-
duce the environmental impacts associated with the extraction,
processing, conversion to usable form, and transportation of
fossil fuels.
Solar energy is not a completely pollution-free source
of energy, however. Although solar energy heating and cool-
ing systems will not be direct sources of significant air or
water pollution, many potential negative environmental impacts
are associated with their widespread utilization. The most
important of these environmental impacts are not directly
associated with the operation of the equipment but rather
with the production of materials for solar systems. The de-
velopment of a solar energy industry that will supply a sig-
nificant portion of national energy requirements by the turn
of the century will entail the diversion of large quantities
of materials, such as glass and copper, for the manufacturer
of solar system components. The pollutants generated in the
extraction and production of these materials must be consid-
ered environmental impacts of solar energy utilization.
In addition to air, water, and solid waste pollution,
other environmental effects must be considered which are more
subjective in nature. These environmental considerations in-
clude:
Land use patterns for solar energy collection
Thermal effects on local meteorology
Toxicity and flammability of solar system working
fluids and materials
Consumer safety implications
Impact on population distribution.
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In order to assess - the net environmental impacts of
solar heating and cooling systems, positive impacts must be
compared to negative impacts. This has not been attempted
in a quantitative sense in this chapter. However, the dis-
cussion presented below indicates that it will be possible
to control and to minimize most of the potential negative
impacts of solar energy, as long as potential environmental
problems are identified and corrected early in the develop-
ment of the technology. The discussion also indicates that
the serious negative impacts, such as the air pollution gen-
erated in the production of materials for solar systems, will
be greatly offset by positive impacts, such as the reduction
in air pollution due to a lower rate of fossil fuel combus-
tion.
The discussion of the environmental impacts of solar
energy systems is presented in this chapter in three sections
Expected Market Penetration of Solar Heating and
Cooling Systems
Air, Water, and Solid Waste Impacts
Other Related Environmental Impacts.
1. EXPECTED MARKET PENETRATION OF SOLAR HEATING AND
COOLING SYSTEMS
The rate at which solar heating and cooling systems will
gain market acceptance will depend on several factors:
The initial cost of solar equipment, including
availability of capital, development of manufac-
turing capacity, and economic incentives
The cost and availability of competing fuels, which
may reflect future changes in rate structures
Public attitudes and confidence
Institutional and legal considerations.
Many of these factors will vary on a regional basis.
The cost and optimum size of a solar system will be a func-
tion of climate and geography. The rate structures and avail-
ability of conventional fuels is distinctly regional, as are
public attitudes and institutional/legal barriers. Several
projections of market penetration are illustrated in Figure 1.
Two forecasts of the total number of solar-equipped buildings
are given in Figure 2.
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FIGURE 1
Energy Supplied By Solar
Heating and Cooling
Systems
JO I NT ATOM 1C
ENERGY COMMITTEE
76 80 84 88 92
111
96 2000
References:
1. Westinghouse Electric Corporation, Solar Heating and Cooling of Buildings, Phase
"0" Report, prepared for National Science Foundation, May 1974.
2. TRW Systems Group, Solar Heating and Cooling of Buildings, Phase "0" Report,
prepared for National Science Foundation, May 1974.
3. General Electric, Solar Heating and Cooling of Buildings, Phase "O" Report, pre-
pared for National Science Foundation, May 1974.
4. ERDA, National Plan for Solar Heating and Cooling (ERDA-23A), Oct. 1975.
5. FEA, Project Independence Report, November 1974.
6. Joint Committee on Atomic Energy, Understanding the National Energy Dilemma,
1973.
7. NSF, as cited in "But Not Soon," by Michael Harwood, 77»e New York Times
Magazine, March 16, 1975.
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FIGURE 2
Solar Equipped Buildings
(Cumulative)
V)
o
d 3-
D
CO
it.
O
in
1 *•
4.4
CONSERVATIVE
ESTIMATE (2)
OPTIMISTIC
ESTIMATE (1)
TJ
m
V*r
8
m
II
z c
§5
W Z
o
V)
1975
1980
1985
1990
1995
2000
Sources:
1. ERDA, National Plan for Solar Heating and Cooling (ERDA-23A), Oct. 1975.
2. General Electric, Solar Heating and Cooling of Buildings, Phase "0" Report, pre-
pared for National Science Foundation, May 1974.
-------
Several forecasts have been developed concerning the re-
spective share of the market for residential and commercial
buildings, and for new and retrofit installations. ERDA's
projections to 1985 are summarized in Figure 3.* Single
family residences and multi-family low rise dwellings are
the leading residential candidates; schools will be a major
commercial application.' It can be seen from the figure that
by 1985, commercial solar installations will likely supply
about as much energy as residential solar systems, and that
solar systems will tend to be incorporated into new buildings
rather than retrofit into existing structures.
In summary, several estimates have been made for the
amount and time frame of the potential energy savings result-
ing from solar heating and cooling systems. However, the es-
timates predict energy savings which are significant. In
this case environmental impacts will be significant also.
Consequently in the next sections potential environmental im-
pacts are identified and discussed.
2. AIR, WATER, AND SOLID WASTE IMPACTS
The environmental impacts of solar energy utilization
include the positive impacts associated with a reduced demand
for fossil fuels, and the negative impacts associated with
the production and operation of solar equipment. A compre-
hensive environmental assessment of each of these energy tech-
nologies must address the complete energy "system" for each
technology. The energy system includes the extraction, pro-
duction, distribution, consumption, and disposal of all ma-
terials, equipment, and fuels associated with each energy
supply technology.
The potential environmental impacts of solar heating and
cooling systems, both positive and negative, are summarized
in Table 1. For each type of activity, the pollutant media
which may be affected are identified. These environmental
impacts are discussed in more detail below in the four sec-
tions:
Reduction in Emissions Due to Reduced Fuel Combus-
tion
Increases in Emissions From Production of Materials
ERDA, National Plan For Solar Heating and Cooling, (ERDA 23A),
October 1975.
TRW Systems Group, Solar Heating and Cooling of Buildings, Phase "0"
Report, prepared for National Science Foundation, May 1974 (hereafter
cited as TRW Phase "0" Report.)
-------
FIGURE 3
Energy Supplied By Solar Heating
and Cooling Systems By Building
Type
I
DC
3£
I
SI
s
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Table 1
Potential Environmental Impacts of
Solar Heating and Cooling Systems
Environmental Impacts
Positive Impacts
• Reduced demand for fossil fuels for electricity generation
and on-site combustion results in reduced:
• Extraction of fuels and materials
- Processing of fuels and materials
- Fabrication of equipment
- Transportation of equipment and fuels
- Combustion of fuels and operation of equipment
- Disposal of combustion by-products and used equipment
Negative Impacts
• Increased production of solar systems results in increased:
- Extraction of materials
• Processing of materials
- Fabrication of equipment
• Operation of equipment
• Disposal of used solar system working fluids and components
Pollution Type
Air
•
•
•
Water
•
•
•
•
Solid
•
•
•
•
•
•
•
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Water Quality Impacts
Solid Waste Disposal.
(1) Reduction in Emissions Due to Reduced Fuel Combus-
tion
As a result of the development of solar heating
and cooling in the residential and commercial sectors,
air pollution emissions will decrease because of re-
duced fuel combustion for heating and cooling buildings
and providing domestic hot water, and reduced fuel com-
bustion for electric power generation. The extent to
which this fuel savings will be shared by on-site fuel
combustion and electric generation will vary substan-
tially from region to region, and will depend on a va-
riety of factors including the cost and availability of
competing fuels.
When solar energy use results in decreases in oil
and natural gas combustion in solar-equipped buildings,
the primary emission reduction will occur in the vicinity
of those buildings. The reduction in pollution asso-
ciated with decreased demand for electricity will not
necessarily occur in the vicinity of the buildings using
solar systems. Rather the emission reduction in an ur-
ban area will reflect the extent of solar utilization in
the region as a whole.
In the future, the use of solar energy will most
likely displace coal and oil use for generating elec-
tricity in central power plants, rather than oil or
natural gas use in residential or commercial buildings.
This is because the majority of solar systems will be
installed in new buildings rather than in existing build-
ings, (see Figure 3 previously), and because electricity
provides the largest share of the space conditioning
and hot water requirements of new buildings. Thus in
most situations, reduced air pollution will be due to re-
duced load requirements at central power plants, rather
than reduced pollution at the buildings for which heating
and cooling are required.
The conversion and transmission efficiency of most
conventional power plants is on the order of 30 to 35
percent. Thus, the fuel and pollution savings per Btu
provided by a solar system can be approximately three
times greater when electricity is displaced than the
savings per Btu associated with on-site fuel combustion.
This is in spite of the fact that, in general, fuels
-------
are burned more efficiently at a power plant than in
individual buildings, and pollution control devices are
more applicable to power plants than to furnaces of in-
dividual buildings. An economic analysis examining the
costs of solar heating and cooling systems versus retro-
fit control technology for existing power plants, and
for solar systems versus new power plant construction
would provide a clearer definition of the tradeoffs in-
volved .
For the case of central plant emissions, two dis-
tinct time frames must be considered for the potential
environmental benefits of solar systems:
Near-intermediate term (limited market pene-
tration)
Intermediate-long term (widespread market
penetration).
That is, the amount and type of power plant fuel com-
bustion and pollution reduction will depend upon the
type of load reduction resulting from use of solar energy.
These two cases are summarized below. A more detailed
discussion of how solar energy utilization may affect
electricity generation at power plants is given in Chap-
ter in.
Near-intermediate Term
The use of solar energy during periods of peak
electricity demand will reduce pollution from
peaking units, such as gas turbines or diesel
units, while off-peak use of solar energy will
reduce pollution from base load units. Clearly,
the implications for regions and urban areas
with high coal use are significant. Further
research is warranted to examine the potential
of solar heating and cooling as a technological
option for reducing air pollution in Air Qual-
ity Maintenance Areas.
Table 2 contains an estimate of the poten-
tial fuel savings in 1985 due to solar heating
and cooling systems installed at that time.
This estimate is based on the most optimistic
forecast of energy savings (0.94 quad/year)
given previously in Figure 1. The fuel
savings shown in the table are based on the
<*sumption that solar systems will displace
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Table 2
Reduction in Fuel Use of 0.94 Quads*
Due to Solar Heating and Cooling Systems
If All Fuel Savings Are:
Oil at point of use
Natural gas at point of use
Oil for electricity
Natural gas for electricity
Coal for electricity
Resulting
Fuel Savings
150 million bbl
940 x 109 cu ft
450 million bbl
2820 x 109 cu ft
108 million tons
Percent of Total
1985 Fuel Use
2.4
3.2
8.0
10.8
9.4
Sources:
• U.S. total energy consumption in 1985 will be 102.9 quads:
FEA, Project Independence Report, November 1974 ($11 per barrel scenario).
• Fuel consumption data for 1985:
The Commission on Critical Choices for Americans, Energy: A Plan for Action,
April 1975.
• It is assumed that the thermal conversion/transmission efficiency for power plants
in 1985 will be approximately 33%.
*NSF, as cited in "But Not Soon," by Michael Harwood, The New York Times Magazine,
March 16,1975.
10
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only one fuel. In reality, of course, savings
will be shared by all the fuels shown in the
table. If it is further assumed that emis-
sions will decrease in proportion to fuel sav-
ings, then according to the table, in 1985
emissions from coal combustion could be re-
duced by as much as 9.4 percent of what they
would be without solar systems.
Intermediate-Long Term
Long term potential coal savings and emission
reductions on a nationwide basis are illustrated
in Figures 4 and 5 respectively. In both
figures conservative and optimistic estimates
are given; these estimates reflect the assump-
tion that all fuel savings due to solar heat-
ing and cooling systems will be in the form of
coal burned to produce electricity. It can be
seen from the figures that by the year 2000
the use of solar heating and cooling systems
may produce significant nationwide coal savings
(up to 13.3 percent) and emission reductions.
Widespread use of solar energy may also cause
a curtailment in the rate of construction of
new power plants, thus limiting the growth of
new sources of air emissions. Utilization of
solar systems in certain high population areas
may conceivably alleviate the need for new
fossil plants in remote locations.
Conservation of fossil fuels will result in a de-
crease in emissions during the extraction, storage, pro-
cessing and transportation of those fuels. For example,
air pollution emissions occur during the mining and
cleaning of coal, and during transportation of the coal
(both from handling and from fuels burned to carry the
coal). Thus solar energy utilization has the potential
for reducing air pollution at all points in the fuel sup-
ply combustion and disposal cycle.
(2) Increase in Emissions From Production of Materials
for Solar Systems
One of the most important impacts of the develop-
ment of residential and commercial solar energy heating
and cooling will result from the potentially large de-
mand for materials for solar component production.
Table 3 shows an estimate of the annual air pollution
resulting from the production of glass, aluminum, and
11
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FIGURE 4
Forecasts of Potential Coal
Savings (If All Solar-Induced
Fuel Savings Are Coal)
CONSERVATIVE ESTIMATE
ANNUAL
COAL
USE.
MILLION
TONS
(MT)
2000
1500
1000
500
NATIONWIDE
COAL USE (1)
COAL
SAVINGS
0.08Q (END USE)
10.2 MT
0.8%
COAL USE REDUCED
BY SOLAR HEATING
AND COOLING SYSTEMS (2)
I I
COAL
SAVINGS
0.670 (END USE)
85.2 MT
4.2%
1975
1985
2000
OPTIMISTIC ESTIMATE
2000
ANNUAL 15°°
COAL
USE,
MILLION 1000
TONS
(MT)
500
NATIONWIDE
COAL USE (1)
COAL
SAVINGS
0.94Q(ENDUSE)
120MT
9.4%
I
I
•COAL USE REDUCED BY
SOLAR HEATING AND COOLING
SYSTEMS, 1985 (3) AND 2000 (4)
I I
I COAL
[ SAVINGS
2.1CHENDUSE)
267 MT
13.3%
1975
1985
2000
Sources:
1. The Commission on Critical Choices for Americans, Energy: A Plan for Action. April 1975.
2. General Electric, Solar Heating and Cooling of Buildings. Phase "0" Report, prepared for National
Science Foundation, May 1974.
3. NSF, as cited in "But Not Soon," by Michael Harwood, The New York Times Magazine, March 16
1975.
4. Joint Committee on Atomic Energy, Understanding tile National Energy Dilemma, 1973.
Assumptions:
1. All new residential and commercial buildings which will be equipped with solar systems would have
used electricity for space conditioning which was generated from combustion of coal.
2. Conversion efficiency for electricity generation is 30% (33% thermal efficiency and 8% transmission
loss).
12
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FIGURE 5
Forecasts of Potential Emission
Reductions (If All Solar-Induced
Fuel Savings Are Coal)
4000-
CO 0=
is
< o
3000
2000
1000
CONSERVATIVE ESTIMATE
ANNUAL
END USE
ENERGY
SAVING: 0.08 Q
NO
ANNUAL
END USE
ENERGY
SAVING: 0.67 Q
1200
100
TSP
sox
2000
NO
4000
£
< o
< o
3000
2000
1000
OPTIMISTIC ESTIMATE
ANNUAL
END USE
ENERGY
SAVING: 0.94 Q
1692
141
987
TSP
sox
1985
TSP
3780
ANNUAL
END USE
ENERGY
SAVING: 2.1 Q
22U6
sox
2000
NON
SOURCES: FORECASTS OF ENERGY SAVINGS ARE FROM FIGURE 4
EMISSION FACTORS CORRESPOND TO FEDERAL NEW SOURCE PERFORMANCE STANDARDS
13
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Table 3
Annual Criteria Emissions Associated With
Solar Heating and Cooling Systems
Providing 0.018 Quads Per Year
Material
Glass (soda-lime)
Backing and heat exchange
material (D
• If aluminum (heat controls,
most common process) (2,3)
• If copper, (controlled)^)
Amount
Required
3.2x1 08 kg
2.2 x 10? kg
7.2 x 10? kg
Emissions Produced, Tons Per Year
TSP
330
530
64
S0x
-
1.0
19,800
CO
-
29
HC
-
1.6
NOX
-
10.0
Material/Fuel
Asphalt roofing
Fuel savings
• If all savings are natural
gas at point of use
• If all savings are coal for
electricity (4)
Amount
Saved
1.8 x 10? m2
5.1 x 108 m3
(18 x 109 cu ft)
1.87 x 10 metric tons
(2.1 x 106 tons)
Emissions Saved, Tons Per Year
TSP
9.7
165
2,700
sox
-
5.4
32,340
CO
13.2
175
1030
HC
22
72
310
NOX
-
715
18,800
Sources:
The production levels and pollution data were taken from:
EPA, Control of Environmental Impacts From Advanced Energy Sources, March 1974.
Emission factors:
EPA, Compilation of Air Pollutant Emission Factors, April 1973.
Notes:
(1) Present indications are that copper will be used more than aluminum because it is more
resistant to corrosion.
(2) Existing installations do not generally achieve this degree of control. However, these
data refer to actual installations where controls have been evaluated.
(3) Includes emissions from a power plant burning natural gas to produce electricity for the
electrolysis process.
(4) Emission factors for TSP, SOX and NOX correspond to Federal new source performance
standards; conversion efficiency for power plants is 33%.
Assumptions:
Data reflect production of 300,000 solar systems per year, which will supply 75% of the
annual space conditioning load of 80 MBtu per unit per year for 300,000 housing units.
In other words, the 300,000 units will displace 18 x 1012 Btu (0.018 quads) of fuel annually.
(Solar induced energy savings of 0.018 quads per year is estimated for 1985 in the EPA
report referenced above.)
14
-------
copper for solar system components (primarily collectors).
The table also shows the annual emission reductions re-
sulting from these solar systems, which include those due
to fuel savings and to reduced demand for materials such
as asphalt roofing (which will be replaced by solar col-
lectors) . The production and emission levels in the table
were taken from a^recent study of advanced energy systems
sponsored by EPA. The data developed in that study cor-
respond to production and use of 300,000 solar systems
per year, capable of providing 0.018 quads per year.
The fuel savings shown in the table are per year of
operation, not cumulative. Solar systems manufactured
from the materials shown in the table will cause air pol-
lution reductions for many years after they are put into
use.
With respect to the emission comparison given in
Table 3, note that:
The emission levels are based on assumptions
concerning the extent of emission control for
the manufacturing processes and power plant
coal combustion.
For a given urban area, most of the emission
savings from buildings or power plants will
occur in or near the urban area, while the
emission increases at manufacturing facilities
will occur in regions which may be located far
away. Thus, a net increase in emissions due
to manufacture of solar systems may occur near
glass, aluminum or copper plants, with some
degree of adverse environmental impact in their
respective areas.
The two fuels shown in Table 3 represent the
least possible emission savings (natural gas
consumed at the point of use) and greatest
possible emission savings (coal for electricity).
Actual annual emission savings, for a given
urban area and for the nation as a whole, will
probably be somewhere between the two.
EPA, Control of Environmental Impacts From Advanced Energy Sources,
March 1974.
15
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A comparison of positive and negative air pollution
impacts over the full solar equipment lifetime is shown
in Figure 6. The" emission penalties (emissions pro-
duced) and emission savings are taken from the data in
Table 3, modified to reflect levels of production of
systems capable of saving 0.94 quads per year (the sav-
ings projected previously for 1985 [optimistic case] in
Figure 4). The emission savings in Figure 6 are
based on an equipment lifetime of 15 years. It can be
seen from the figure that on a nationwide basis poten-
tial emission reductions over the full equipment life-
time more than offset emissions resulting from equipment
production for all criteria air pollutants. As indi-
cated above, the emission penalty associated with solar
systems occurs only during manufacture of solar system
materials and components, while the emission savings
occur year after year during the equipment lifetime.
(3) Water Quality Impacts
Utilization of solar heating and cooling systems
may produce positive and negative water quality impacts.
The positive impact will be a reduction in effluent dis-
charge and thermal pollution from power plants due to
the decrease in electricity demand. Power plant efflu-
ents^ usually include chlorine, which is used to minimize
biofouling in the discharge system. This decrease in
electricity demand may lead to reduced requirements
for coal. The corresponding curtailment of mining
operations will alleviate the demand on national water
resources as well as reducing the area of mined lands
which are non-point sources of water pollution.
The potential negative water quality impact is due
to the disposal of solar system working fluids. Wide-
spread use of solar systems will require the development
of central collection facilities for disposal of de-
graded supplies of heat transfer fluids or antifreeze
solutions. Disposal of waste fluids such as antifreeze
is not a new problem but because these fluids are likely
to be used by individual consumers in quantities that
are quite large, considerable care must be taken to
avoid potentially harmful dumping.
(4) Solid Waste Disposal
Two types of solid waste disposal problems may
occur with solar energy systems: the solid waste
16
-------
FIGURE 6
Comparison of Positive and
Negative Air Pollution Impacts
(15 Year Life-Cycle Basis)
TSP
so_
CO
HC
NO.
op I 1200T
°- if z
g 5 5 soo
- < d
I ? 400 +
uj O
=3 U
O u. :rr
O
S 5
400 - -
800--
1200 - -
1600--
2000--
>
14400 - -
14800 - -
f
25200 - -
25600 -L
45 21
(O
1034
(A)
.05
2127
25334
817
(A)
.09
(A) - Aluminum Collectors
(C) - Copper Collectors
(A)
.5
73
260
560
1
1
14735
If all fuel savings are natural gas at point of use
If all fuel savings are coal burned to produce electricity
Source: Emission data presented in Table 3; solar equipment lifetime assumed to be
15 years; system production levels correspond to annual energy savings of 0.94
quads per year (end use).
17
-------
residuals associated with the production of system com-
ponents, and the disposal of those components when they
are no longer needed.
The solid waste residuals generated during the pro-
duction of solar components include those from the ex-
traction of raw materials, the refining of these mate-
rials, and the fabrication and assembly of components.
The major materials of solar systems are glass, copper,
and aluminum; there are solid waste residuals which are
associated with the mining of metals and minerals, and
the refining of these materials to produce the primary
metals and glass. There are also solid waste residuals,
primarily scrap wastes, from the fabrication and assem-
bly of components.
The disposal of used solar system components should
not present significant problems. It is important that,
whenever possible, recyclable materials be used in the
manufacture of solar systems so that environmental im-
pacts of solar energy are not compounded by the produc-
tion of unnecessary solar-related wastes. Furthermore,
solar system specifications should encourage the use of
materials which are plentiful so that environmentally
costly extraction technologies are not encouraged. A
recycling program should probably be considered an in-
tegral part of the commercialization of solar heating
and cooling technology.
3. OTHER ENVIRONMENTAL IMPACTS
In addition to the air, water and solid waste residuals
associated with solar systems which were discussed in the
previous section, there are other environmental effects which
are more subjective in nature. These potential impacts, which
include aesthetic, social, and consumer safety considerations,
are discussed in this section.
(1) Effect on Land Use Patterns
1. Zoning
The widespread use of solar energy will have
a very visible impact on the manner in which land is
utilized, since large quantities of land will be af-
fected. Even for residential and commercial uses of
18
-------
solar energy for heating and cooling buildings, it
may be necessary to set aside substantial land areas
especially for solar collectors. Building spacing
and building height must be planned carefully to
maximize collector exposure to the sun. Thus, zoning
laws will specify in more detail the type of develop-
ment permissible on different parcels of land.
If rooftop collectors become widespread, zoning
problems will be solved more easily if areas of land
are zoned with respect to the minimum as well as the
maximum height of buildings. The more uniform the
height of buildings in a particular development, the
fewer the problems with sunlight obstruction. Fi-
nally, proper spacing in the interface between zones
reduces obstruction problems. Use of solar energy
will, therefore, generally entail a less concentrated
use of land than is the current practice in urban
areas.
It will be necessary to review residential
landscaping concepts in accordance with the need
for maximum solar exposure. This will mean that
the use of trees in close proximity to buildings
may be curtailed. An energy-related effect of
fewer trees is that natural cooling of buildings
because of shading may be reduced. Solar systems
which include heating but not cooling capabilities
will be less seriously affected by the presence of
trees close to the building. During much of the
winter the trees will be bare, and in summer the
trees will help reduce the conventional cooling
load.
The issue of "sun rights" can be avoided with
proper zoning and building orientation in the case
of new developments. A body of legal precedent in
this area may develop as a result of dispute over
the right to sunshine of existing buildings. Wide-
spread use of solar energy could place a limit upon
the extent to which existing urban areas are fur-
ther developed. For example, a doctrine in British
common law known as the doctrine of "ancient lights"*
limited the extent to which tall buildings were con-
structed in London. The establishment of a legal
right to sunlight in American law could have a simi-
lar impact.
This common law doctrine defined the right of persons living or
working near ground level to a sunlit environment.
19
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2. Aesthetics and Building Orientation
Utilization of solar energy use could influ-
ence residential and commercial architectural styles.
The design of collector configurations as integral
parts of roofs and the use of concentrating surfaces
could radically change building styles. These ef-
fects would probably be mitigated, however, because
public tastes, especially in the case of single-
family homes, have always been conservative and not
very susceptable to rapid change. Building codes
also discourage innovation to some extent. Similarly,
the building industry is slow to adapt to new styles.
Therefore, solar systems are likely at first to be
incorporated into existing accepted building styles
and any changes are likely to evolve slowly over
many years.
(2) Thermal Effects on Local Meteorology
The impacts in terms of direct thermal pollution of
the use of solar energy in residential and commercial
space heating, hot water heating and space cooling appli-
cations will be minimal. Space heating and hot water
heating systems are closed systems which do not reject
heat to the external environment. Solar cooling systems
involve heat rejection from the cooling tower as well as
minor cooling water bleed off but these effects are not
expected to have any significant impact on the environ-
ment.
Many cities have become "heat islands," partly be-
cause of the release of heat energy associated with many
forms of human activity. In a similar way, the use of
large areas of solar collectors in urban areas may in-
fluence weather conditions, since some of the sunlight
that is normally reflected from buildings back into the
atmosphere will be captured by the collectors. This may
affect temperature gradients in the air, which are sig-
nificant determinants of wind, cloud-cover, atmospheric
mixing and, ultimately, air quality. There could be a
feedback effect because increased cloud-cover will alter
the effectiveness of solar collectors. Further study in
this area is necessary to determine the potential extent
of these impacts.
Research is now underway in this area sponsored by the Electric
Power Research Institute as part of a study of the environmental
impacts of solar thermal electricity generation.
20
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Large collector networks can disturb the natural
heat balance by reducing ground temperatures and there-
by may impact plant and animal life. These potential
impacts can be expected to be much more serious in the
case of central station solar thermal electricity gen-
eration, where vast areas of land devoted to collection
equipment may be required. Much more detailed research
in this area is also required.
(3) Toxicity and Flammability of Solar System Fluids
and Materials
Materials used in solar heating and cooling systems
do not in general present a significant problem with re-
spect to risk of accidental release of toxic materials.
The components of solar collectors must be tested, how-
ever, to ensure that corrosion or erosion due to long
exposure to the environment will not result in the re-
lease of potentially harmful substances. Since solar
systems will be composed of materials already in common
use, such as copper, aluminum, steel, and glass, no spe-
cial problem in this area should be anticipated.
Working fluids must be carefully examined for simi-
lar impacts in case of accidental release from the sys-
tem, in general, no major problems are currently fore-
seen by manufacturers of solar systems, although the
flammability of certain substances which may be used in
heat transfer and heat storage devices may present a
problem. To date, researchers have limited development
efforts in the area of heat transfer fluids and heat
storage materials to substances with fairly low poten-
tial toxic effects. In addition, building code restric-
tions on the amount of ammonia that can be used inside a
building will require that absorption cooling systems
using ammonia as the refrigerant be located on the ex-
terior. This will eliminate problems that could arise
due to the moderate toxicity and potential flammability
of ammonia. Table 4 summarizes possible environmen-
tal or health effects associated with heat transfer
fluids, refrigerants, absorbents, corrosion inhibitors,
wetting agents, and heat storage materials which are
likely to be used in solar systems.
(4) Consumer Safety Implications
Certain characteristics of solar systems may pre-
sent limited hazards to consumers and to the general
21
-------
Table 4
Characteristics of Solar System Working Fluids
CHEMICAL SUBSTANCE
1. Heat Transfer Fluids
• Dimethyl Siloxane
Polymers (Dow
Corning 200)
• Aromatic Hydro-
carbons (Monsanto
Therminol Fluids
e.g. Therminol 55,
Therminol 60)
• Diethyl Benzene
(Dowtherm J)
• Paraffinic Oil Mix-
tures (Dowtherm HP}
• Ethylene Glycol
• Fluorocarbons
(e.g. Dupont Freons,
such as Freon 113)
ADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Low freezing pt.; high
dielectric strength (use
with dissimilar metals);
high boiling pt.; thermal
stability; good, viscosity-
temperature characterises
Low freezing pt. (60°F
typical); high boiling pt.
(600°F typical); thermal
stability
Low freezing pt. (-100°F);
High boiling pt. (358°F);
low viscostly ; easy to
pump; thermal stability
Very high boiling pt.
(680°F)
High boiling pt. (356°F);
lowfreezingpt. (8°F);
used in solution with
water, so higher heat
capacity than above
fluids
Low freezing points;
thermal stability
DISADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Heat capacity about half
that of water; although
fluids with a wide range of
viscosities are available.
only fluids with viscosities
of 50 centistokes or less
can be centrifugally
pumped below 40° F
Heat capacity about half
that of water
Lower heat capacity than
water
Viscous at low tempera-
tures; not suitable for use
in cold climates; lower
heat capacity than water
Higher freezing point than
above fluids
Most freons have a low
boiling point, therefore, to
use these fluids some
collector pressurization
would be needed; lower
heat capacity than water
TOXICITY
Low toxicity, although
temporary irritation
caused by direct contact
with the eyes
Moderate; comparable in
toxicity to light mineral
oil; toxic if ingested;
mildly irritating if contacts
eyes; vapors mildly irritat-
ing with prolonged expo-
sure
Moderate; comparable in
toxicity to kerosene; tox-
icity comparable to ther-
minol fluids
Low toxicity; a laxative;
may cause aspiration
pneumonia
Toxic if ingested; low
toxicity otherwise
Toxicity unknown but
believed to be moderate
FLAMMABILITY
Low hazard; high flash points
Low hazard; flash points above
300°F
Moderate hazard if in contact
with a source of ignition; flash
point: 145°F; fire point: 155°F
Low hazard; flash pt. greater
than 440°F
Slight hazard if in contact with a
source of ignition; flash point: 232°F
Very slight when exposed to heat
or flame
NJ
NJ
-------
Table 4
(Continued)
to
GJ
CHEMICAL SUBSTANCE
2. Solar System Heat
Storage Materials
• Salt Hydrates (e.g.
Sodium Sulfate
Decahydrate)
• Paraffin Wax
• Diphenyl
• Diphenyl Oxide
3. Absorption Refrigeration
Fluids
• Lithium Bromide
ADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Far less volume and
weight than water per
btu stored; non-corrosive
Less volume per btu
stored than water
Less volume per btu
stored than water
Less volume per btu
stored than water
Water/lithium bromide
refrigerant/absorbent
combination most comon-
ly used in absorption cool-
ing; conventional lithium
bromide units can be de-
rated to operate at temp-
eratures supplied by solar
collectors
DISADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Limited lifetime: currently,
2-3 years, research ongoing
to improve this to 5-10
years
Lower heat of fusion than
salt hydrates; phase change
in paraffins accompanied
by 10% loss in volume
Generally, a lower heat of
fusion than salt hydrates
Generally, a lower heat of
fusion than salt hydrates
Lithium bromide crystal-
izes if cooling unit oper-
ated too far below design
capacity
TOXICITY
Materials that have been
tested were chosen for
low toxicity
Low toxicity; minor irri-
tation from prolonged
exposure
Moderate to high w.r.t.
inhalation and ingest ion
Moderate
No toxicity problem re-
ported toxicity low in
small quantities
FLAMMABILITY
Materials are non-flammable and
non-combustible
Slight hazard; flash point: 390°F
Slight hazard
Moderate hazard when exposed
to heat or flame
No flammability hazard
-------
Table 4
(Continued)
CHEMICAL SUBSTANCE
3. Absorption Refrigeration
Fluids (Continued)
• Ammonia
• Lithium Chromat
• Lithium Nitrate
• Lithium Hydroxide
• 2-Ethylhexanol
• Sodium Chromate
• Sodium Hydroxide
ADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Ammonia/water refrig-
erant/absorbent combin-
ation does not have prob-
lem with f reezeup during
low-temperature opera-
tions
Used in water/lithium
bromide cooling systems
as a corrosion inhibitor
Used in water/lithium
bromide cooling systems
as a corrosion inhibitor
Used in water/lithium
bromide cooling systems
to control acidity
Used in water/lithium
bromide cooling systems
as a wetting agent
Used in ammonia/water
cooling systems as a
corrosion inhibitor
Used in ammonia/water
cooling systems to con-
trol acidity
DISADVANTAGES
FOR
SOLAR
SYSTEM APPLICATION
Ammonia/water systems
operated at higher pres-
sures than water/lithium
bromide systems; cop
found, generally, to be
slightly lower
TOXICITY
Moderate toxicity w.r.t
irritation and inhalation;
severe toxicity w.r.t. inges-
tion; vapor can cause skin
burns
High toxicity w.r.t. irrita-
tion, ingestion, inhalation
Moderate toxicity w.r.t.
ingestion and inhalation
ingestion: dizziness,
abdominal cramps, inhala-
tion: weakness, headaches
Moderate toxicity w.r.t.
ingestion and inhalation;
see sodium hydroxide,
below
Slight toxicity
High toxicity w.r.t. irrita-
tion, ingestion, inhalation
Moderate-high toxicity
corrosive action on tissue
causes burns; vapor can
damage eyes; inhalation
can damage upper respira-
tory tract
FLAMMABILITY
Slight hazard; when heated emits
toxic fumes
Slight hazard; an oxidizer; it can
react with reducing materials
Moderate hazard, by spontaneous
chemical reaction
No flammability hazard
Moderate hazard when exposed to
heat or flame
Low flammability
Low flammability hazard
-------
public. The large areas of glass in solar collectors,
for example, may pose breakage problems during installa-
tion, maintenance, or operation. However, this hazard,
and the others summarized below, certainly do not exceed
the hazards associated with using similar materials in
other applications.
1. Collector Plumbing Problems; Leaks, Over-
pressurization, Boiling
Plumbing for solar systems must be stronger
than conventional hot water plumbing because tem-
peratures and pressures in excess of those of con-
ventional domestic hot water systems occur in solar
systems.
2. Use of Antifreeze and Anticorrosion Compounds
in the Collector Loop
Solar systems must be designed with double
walled heat exchangers between the collector loop
and the domestic hot water supply. If this is not
done, a significant consumer hazard will exist be-
cause a failure in the wall of a single-wall ex-
changer would contaminate the potable hot water
supply with antifreeze or anticorrosion compounds.
3. Safety of Solar Absorption Cooling Devices
In general, there will actually be a slightly
lower risk of explosion or leaks in solar absorp-
tion cooling units than in conventional absorption
cooling units because the systems will operate at
lower maximum temperatures.
4. Structural Issues: Roof and Wind Loading
The roofs of solar homes must withstand the
additional weight of solar collectors. In general,
this is not likely to present a problem, but it
could limit the extent to which homes can be retro-
fitted with solar systems in a few parts of the
country where building codes allow very light roof
construction. Solar collectors must also be at-
tached to the roofs with great care to prevent the
possibility of accidents during high winds.
25
-------
(5) Impact on Population Distribution
The development of solar energy will entail certain
long-term trends with respect to population distributions.
First, solar energy will encourage development of decen-
tralized population patterns. This will result in fur-
ther development of suburbs and of widespread, diffuse
metropolitan areas rather than more concentrated cities.
This is consistent with recent trends which show for the
first time a net movement in population away from large
cities and towards smaller cities.
Solar energy utilization may have an impact on the
cost of living in the long term if life cycle solar
energy costs are significantly lower than those of other
energy forms. The widespread utilization of solar energy
may encourage movement of population towards areas of the
country with the highest degree of insolation, such as
the southwestern states. (Solar desalinization tech- •
nology is potentially important in such areas as well,)
The accelerated economic development of these areas of
the country will entail environmental impacts which
would not otherwise have been expected.
The significant conclusions of this chapter are summa-
rized below:
Net energy supplied and net pollution should be key
considerations in comparing solar energy utiliza-
tion to total fossil fuel cycles (the coal cycle,
for example, includes the extraction, processing
and transportation of coal)
Several studies indicate that solar heating and
cooling systems may conserve on the order of 100
million tons of coal annually (optimistically by
1985, conservatively by 2000). This does not in-
clude additional savings which might be due to
other solar technologies (e.g., solar electric
generation and biomass conversion)
Conservation of coal resulting from solar energy
utilization will reduce acid water runoff and
surface disfiguration associated with coal mining,
and will conserve water resources. Reduced
demand for electricity corresponds to a decrease
in thermal pollution and effluent and solid waste
residuals.
26
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Nationwide annual reductions in air pollution due
to decreases in coal combustion may be on the order
of 1.2 million tons of SOX; 100,000 tons of TSP;
and 700,000 tons of NOX (optimistically by 1985,
conservatively by 2000)
The environmental benefits of solar heating and
cooling systems outweigh the environmental penal-
ties on a nationwide basis for net air and water
pollution
An important consideration in the design and manu-
facture of solar system components is that scarce
or depletable materials or toxic substances not be
used
A recycling program should be an integral part of
the marketing of solar systems
Several other environmental aspects of solar energy
utilization should be monitored as the technology
is developed and commercialized, including aesthetic,
consumer safety, meteorological and social consider-
ations. Many of these other environmental consid-
erations could be studied quantitatively in the
same way that air pollution impacts were addressed
in this report.
It is recommended that additional research be directed
to the following:
An economic comparison of the cost per quad of
energy delivered by (1) solar heating and cooling
systems and (2) conventional coal-fired power plants,
for the period 1985-2000. Costs associated with
generation of electricity include the costs of
coal mining and surface restoration, coal trans-
portation, construction and maintenance of power
plants and transmission lines, and pollution control.
Regional analyses of how utilization of solar heating
and cooling may alleviate the need for construction
of new fossil fuel power plants. These analyses
should consider those regions where health effects
of air pollution are or will be critical, or regions
to which electricity will be supplied from power
plants in remote areas where air quality is now
pristine.
27
-------
A more detailed evaluation of the potential of
solar heating and cooling systems as a technological
option for controlling air pollution by inclusion
in Air Quality Maintenance Plans and State Imple-
mentation Plans.
28
-------
II. THE ROLE OF SOLAR HEATING AND COOLING IN THE
CONTEXT OF THE NATION'S OVERALL ENERGY PROGRAM
-------
II. THE ROLE OF SOLAR HEATING AND COOLING IN THE
CONTEXT OF THE NATION'S OVERALL ENERGY PROGRAM
This chapter summarizes national programs for research
and development of solar heating and cooling technology, and
describes how these programs address environmental considera-
tions. This discussion is presented in five sections:
The national energy plan
Federal agency responsibilities in the area of
solar heating and cooling
The role of Federal agencies in major solar heating
and cooling demonstration projects
The role of EPA in solar energy development
Federal agencies concerned with environmental im-
pacts of solar heating and cooling systems.
1. THE NATIONAL ENERGY PLAN
(1) The Goals of the National Energy Plan
The Energy Research and Development Administration
(ERDA) has been designated the lead agency for energy-
related research. As required by the Energy Reorganiza-
tion Act of 1974 (PL 93-438), ERDA has identified na-
tional energy goals and has developed a national energy
R&D program plan (ERDA-48)*, which identifies Federal
energy programs and milestones necessary to obtain the
objectives of the program.
The national energy plan focuses on accelerating
commercial acceptance of technologies for the supply
ERDA, A National Plan For Energy Research, Development, and
Demonstration (ERDA-48), 2 volumes, June 1975.
29
-------
and conservation of energy. The specific goals of the
plan include:
Expanding the domestic supply of economically
recoverable raw materials used for producing
energy
Increasing the utilization of essentially in-
exhaustible domestic energy resources
Transforming existing fuel resources into more
desirable forms
Increasing the efficiency and reliability of
the processes used in the energy conversion
and delivery systems
Transforming consumption patterns to improve
energy utilization of under used resources
Increasing end-use energy efficiency
Performing basic and supporting research and
technical services related to energy
Protecting and enhancing the general health,
safety, welfare, and environment related to
energy.
It should be noted from the last point above that a
concern for environmental effects of energy utilization
is a specific objective of the program.
The national energy plan was developed to be broad
enough to include all the alternative technologies now
being developed and yet flexible enough to permit devel-
opment of a range of new energy technology options. This
flexibility is important at the present time because of
changes in resource availability, international politics,
and domestic economic considerations. Recently, ERDA
has emphasized energy conservation as the near-term ob-
jective of highest priority.
30
-------
(2) Technology Options Addressed in the National
Energy Plan
Achieving the goals of the national energy plan
will require the development of new energy technologies.
Several energy technology options have been identified
in the program plan as the focus of an intensive RD&D
effort. These technology options range from those which
are currently commercially available to those not yet
developed beyond the laboratory stage. The technologies
are identified and prioritized below in Table 5:
Table 5
Ranking of RD&D Technologies
Priority
Highest priority
technologies*
Other high
priority
technologies*
Energy Technology
Near-Term
«1985)
Direct utilization
of coal
Converter reactors
for nuclear
Enhanced recovery
of oil and gas
Conversion of waste
materials to energy
Mid-Term
(1985-2000)
Gaseous and
liquid fuels
from coal
Fuel from oil
shale
Geothermal
Solar heating and
and cooling
Long-Term
O2000)
Breeder reactors
Nuclear fusion
Solar electric
Fuels from biomass
Hydrogen energy
systems
Source: ERDA, A National Plan for Energy Research, Development
and Demonstration (EROA-48), 2 volumes, June 1975.
The priority scheme above reflects the capability of the technology
to supply energy in the timetable indicated.
31
-------
The development of these technologies could result
in a contribution of up to 145 x 1015 Btu per year to
the nation's energy supplies by the year 2000. This is
equivalent to the energy supplied by 20 billion barrels
of oil.
(3) The Role of Solar Heating and .Cooling in the
National Energy Plan
Solar technology, which until now has not made a
significant contribution to the nation's energy supply,
has the potential to make a significant impact as a new
energy resource over the next several years.
As shown previously in Table 5, two solar energy
options (solar electric, and solar heating and cooling)
have been identified as technologies whose development
can substantially augment our domestic energy supplies
in the mid- and long-term.
Solar Electric. The sun's radiant energy is
converted to electricity, either by capturing
radiant energy in collector systems and con-
verting it directly into electrical power using
photovoltaic devices, or by using the solar
energy to heat a working fluid which is then
used to operate a steam turbine power plant.
The collector system for the latter approach,
called solar thermal power generation, can be
a solar "farm" (a large number of linear col-
lectors used to heat the working fluid) or a
solar furnace (light energy from different lo-
cations is focused on a single heat exchanger.)
In a somewhat broader context, the use of wind
or ocean thermal gradients as the input energy
source can also be considered part of this
technology.
Solar Heating and Cooling. The sun's light
energy is utilized to provide space heating
or cooling, or domestic hot water, for build-
ings. While these buildings may be residen-
tial, commercial, industrial or agricultural,
the residential and commercial type are con-
sidered to be the most promising applications.
A typical solar heating system involves a flat
plate collector using water or air as the
32
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working fluid, a sensible or latent heat stor-
age system, and water or air as the space
heating working fluid. Solar cooling may be
accomplished using conventional heat actuated
refrigeration systems or nocturnal radiation.
The combined heating and cooling systems are
ordinarily more economical than separate sys-
tems.
Together, solar electric and solar heating and cool-
ing may contribute over six percent of the additional
energy anticipated from the development of all the alter-
native energy options listed in Table 5. In terms of
equivalent barrels of oil, solar technology may save 1.6
billion barrels (about 9.1 x 1015 Btu's per year) by the
year 2000. This total is composed of anticipated savings
of the equivalent of nearly 600 million barrels of oil
from the application of solar electric technology and
the savings of the equivalent of over 1 billion barrels
from solar heating and cooling systems alone.
Utilization of solar energy for heating and cooling
is especially important because the technology is well
developed and because the potential energy contribution
is large. The energy consumed for space heating, air-
conditioning, and water heating is currently about one
fourth of all the energy consumed in the U.S.; essen-
tially all of this energy is supplied by combustion of
fossil fuels. This report is directed to the environ-
mental aspects of solar technology which may supply a
significant part of this percentage.
2. FEDERAL AGENCY RESPONSIBILITIES IN THE AREA OF SOLAR
HEATING AND COOLING
To achieve the objectives of increased RD&D in the areas
of solar heating and cooling identified in the national
energy plan, an Interagency Task Force chaired by ERDA has
prepared a comprehensive plan for management of the solar
heating and cooling program and coordination of the activi-
ties of other Federal agencies participating in the program.
This plan is discussed briefly in the following sections.
ERDA-48, volume 2 (6.3% of 144.5 quads by the year 2000)
33
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(1) The National Plan for Developing Solar Heating
and Cooling^Technology
The objectives and schedule of the solar heating
and cooling plan calls for commercial acceptance in
time to make energy contributions before 1985, and for
a substantial contribution to the nation's energy sup-
plies by the end of the century. To accomplish this,
ERDA has developed a National Plan for Solar Heating
and Cooling (ERDA-23A, October 1975) to achieve the fol-
lowing objectives:
Place emphasis on the early commercialization
of heating and cooling systems in residential
and commercial buildings
Demonstrate this technology by 1979
Involve private industry in the demonstration
of this technology
Direct Federal resources to disseminate tech-
nical, economic data, and other information
to the public and private sectors
Coordinate Federal activities directed at
demonstrating this technology, improving sys-
tem performance and reducing costs.
To achieve these objectives, the plan is structured
into five program elements:
A residential demonstration program
A commercial demonstration program
R&D in support of the demonstration programs
A research and advanced systems development
program
An information dissemination program.
These program elements are discussed in more detail
below.
The purpose of the residential and commercial dem-
onstration programs in general is to enhance the market-
ability of solar heating and cooling systems. .Specific
34
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goals to accomplish this objective are to demonstrate
the feasibility of the technology, to encourage private
sector participation (A&E firms/ HVAC contractors, and
the construction industry) and to build public and con-
sumer confidence in solar systems. The programs are de-
signed to lower system costs by stimulating demand among
consumers and by providing a mechanism for the private
sector to gain practical solar system expertise. Valu-
able by-products of the demonstration programs will be
the collection of solar system operating data on a wide
geographic basis.
Research in support of the demonstration programs
will include the evaluation and testing of prototype
systems and subsystems specifically for use in the dem-
onstration program. Government support of industrial
research in this area will result in a wider variety of
technology options, and at an earlier date, than other-
wise would be expected. Concurrently, research, and de-
velopment of advanced systems will be conducted to fur-
ther develop the state-of-the-art of solar system com-
ponents. The information dissemination program will
collect and distribute information on the results of
government RD&D programs and demonstrations to acceler-
ate the widespread acceptance of this technology.
Estimates of funding levels of these five program
elements, while still preliminary, indicate relative
program priorities. Preliminary funding levels, which
reflect the maximum number of demonstrations proposed
in ERDA 23A, are shown in Table 6. This information
indicates that the residential and commercial demonstra-
tions may account for as much as 59 percent of the solar
heating and cooling budget.
35
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Table 6
Budget Levels for Solar
Heating and Cooling Program
FY 1975 - FY 1979
Program Element
Residential Demonstration
Commercial Demonstration
Development in Support of
Demonstrations
Advanced R&D
Information Dissemination
Total
Million
Dollars
69
112
38
79
9
307
Percent
of Budget
22
37
12
26
3
100
Source: ERDA23A
(2) Federal Agency Involvement in Solar Heating and
Cooling RD&D
There were four laws passed in 1975 defining solar
heating and cooling programs and Federal agency respon-
sibilities :
The Solar Heating and Cooling Demonstration
Act of 1974, PL93-409, September 3, 1974
The Energy Reorganization Act of 1974, PL93-
438, October 11, 1974
The Solar Energy Research, Development, and
Demonstration Act of 1974, PL93-473, October 26,
1974
The Federal Nonnuclear Energy Research and De-
velopment Act of 1974, PL93-577, December 31,
1974.
The legal requirements of these four acts and -the speci-
fic requirements for interagency relationships have been
36
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addressed in detail by the Science Policy Research Divi-
sion of the Library of Congress. In the discussion
which follows, general agency responsibilities are dis-
cussed.
The legislation mentioned above authorizes ERDA
and other Federal agencies to carry out solar heating
and cooling programs and to pursue the effective and
early utilization of these systems. More precisely,
ERDA's responsibilities in helping to develop solar
energy technology, in addition to overall program man-
agement and coordination, include:
The development of a solar energy data base
Research and development of solar energy tech-
nologies
Demonstration of solar heating and cooling
energy technologies
Establishment and operation of a solar energy
information data bank
Establishment of a Solar Energy Research In-
stitute (SERI) to assist in advancing solar
energy use and in furthering the dissemination
of this technology
International cooperation of the field of
solar energy.
ERDA is directed to carry out these responsibilities
in cooperation with the following departments and agen-
cies:
Department of Housing and Urban Development
(HUD)
Department of Defense (DOD)
National Aeronautics and Space Administration
(NASA)
Federal Interagency Coordination of Nonnuclear Energy Research and
Development, June 6, 1975. Dorothy M. Bates, Science Policy Re-
search Division, Congressional Research Service, Library of Con-
gress.
37
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General Services Administration (GSA)
National Bureau of Standards, Department of
Commerce (NBS)
National Science Foundation (NSF)
Federal Energy Administration (FEA)
Department of Agriculture (USDA)
Department of the Interior (DOI)
National Oceanic and Atmospheric Administra-
tion, Department of Commerce (NOAA)
Department of Health, Education, and Welfare
(HEW)
Agency for International Development, Depart-
ment of State (AID)
Postal Service (USPS)
Federal Trade Commission (FTC)
Federal Power Commission (FPC).
Table 7 highlights the major areas of responsi-
bility of these Federal agencies in the area of solar
heating and cooling technology.
Having summarized the general responsibilities of
each Federal department and agency participating in the
program, it is appropriate to summarize agency respon-
sibilities on a program element/task basis (Table 8).
3. THE ROLE OF FEDERAL AGENCIES IN MAJOR SOLAR HEATING AND
COOLING DEMONSTRATION PROJECTS
The National Solar Heating and Cooling Plan (ERDA 23A)
provides for the demonstration of solar technology for resi-
dential and commercial building applications to encourage
commercial acceptance of these energy systems. The demon-
strations will build public confidence in the technology and
will enable the private sector to gain practical solar system
expertise.
A limited number of buildings have already been equipped
with solar heating or cooling systems, either initially or
a retrofit basis. To date these have been largely R&D ex-
periments designed to advance the state of the technology.
Solar systems are operating in about 30 residences, two of-
fice buildings and four schools.
38
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Table 7
Federal Agency Areas of Responsibility
for Solar Heating and Cooling (Agency Basis)
Agency
Specific Areas
of Responsibility
• FEA
HUD
NASA
NSF
Mitigate the economic, institutional,
and legal barriers hindering the com-
mercialization of solar energy
technologies
Stimulate market demand for these
systems
Develop solar energy manufacturing
capability
Assure that solar energy development
activities are properly coordinated
with other energy development activ-
ities and energy conservation programs
Jointly with ERDA, manage and
operate the residential solar heating,
cooling, and domestic hot water
demonstrations
Jointly with NBS, develop performance
criteria for residential solar heating and
cooling systems
Disseminate information to promote the
practical use of solar heating and cooling
technology; establish a data bank"! (to
be managed by ERDA)
Provide component and system develop-
ment, testing and evaluation support to
the solar heating and cooling demon-
stration program
Conduct R&D on advanced solar heating
and cooling systems
Providing program management
expertise
Conduct basic and high risk research
in the solar energy field
39
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Table 7
(Continued)
Agency
Specific Areas
of Responsibility
NSF
(Cent.)
• NBS
• NOAA
• DOD
• USDA
• GSA.DOI
DSPS
• HEW
• FPC, FTC
• AID
Educate personnel to perform
solar energy RO&D
Disseminate information to the
national and international community
Update performance criteria for
solar heating and cooling components
and systems. They will take the lead
in coordinating the adoption of
industry standards.
Provide weather and insolation data
Arrange for installation of solar
heating and cooling systems in
buildings on Federal property
Manage commercial demonstrations
related to agricultural applications
of solar heating and cooling systems
Conduct solar heating and cooling
demonstrations in agency buildings
Identify buildings (hospitals,
schools) for utilization in the
commercial demonstrations
Determine the potential effects of
substitution of solar energy systems
on the low-income sectors of the
population
Analyze regulatory, policy, and
trade implications
Assist in international aspects of the
program
1
The Solar Heating and Cooling Data Bank will collect, review, process, and disseminate this information and data at WE
provide retrieval and discemination support for all government agencies, the academic community, nonprofit organize!
•nd provide individuals upon request.
40
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Table 8
Federal Agency Areas of Responsibility
for Solar Heating and Cooling (Task Basis)
PROGRAM ELEMENT
LEAD AGENCY
PARTICIPATING
AGENCIES1
1. RESEARCH AND DEVELOPMENT PROGRAM
A. RESEARCH ERDA
Building Designs
Components & Materials
Advanced Systems
Systems Analysis
Insulation & Climatic Data
B. DEVELOPMENT FOR DEMONSTRATION PROGRAM ERDA
System Design & Development
Site Data Collection
Purchase/Development of Subsystem
Engineering Support
Test & Evaluation
C. ADVANCED SYSTEMS DEVELOPMENT ERDA
• System/Component Development
• Integration of Subsystems
2. RESIDENTIAL DEMONSTRATION PROGRAM
A. PROGRAM DESIGN & MANAGEMENT
• Program Preparation/Management
• Environmental Impact Statements
B. ESTABLISHMENT OF PERFORMANCE CRITERIA & HDD0
STANDARDS
• Develop and Monitor Standards
• Certify Testing Labs
C. CONDUCT OF DEMONSTRATIONS HUD4
• Subsystem, Site Selection
• Construction and Operation
D. DATA COLLECTION HUD
E. MARKET DEVELOPMENT TO ENHANCE
COMMERCIAL & PUBLIC ACCEPTANCE HUD
3. COMMERCIAL DEMONSTRATION PROGRAM
A. PROGRAM DESIGN & MANAGEMENT ERDA
• Program Design
• Technical Reqmt's
• Environmental Impact Assessment
ERDA/HUD JOINTLY2
HUD, NASA, FEA, DOD,
NSF, GSA, NBS, NOAA
HUD, NASA, DOD,
GSA, NBS
NASA, DOD, NSF
NASA, FEA, DOD, GSA,
NBS, NOAA, EPA
ERDA, NASA, FEA,
DOD, NSF, GSA, NBS
ERDA, NASA, FEA,
DOD, NBS
ERDA, NASA, FEA,
DOD,NBS
ERDA, FEA. DOD,
NBS
HUD, NASA. FEA, DOD,
GSA, NBS, USDA, USPS,
DOI.HEW, EPA
Support provided by utilizing resources of agency and/or providing consultation services.
Joint overall responsibility for program and for program preparation/management. HUD is lead agency for balance of program
elements.
Joint responsibility with ERDA on developing intermediate minimum property standards.
Joint responsibility with ERDA in selecting solar systems and in integration of them into demonstration project.
Source: ERDA23A
41
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Table 8
(Continued)
PROGRAM ELEMENT
LEAD AGENCY
PARTICIPATING
AGENCIES
B. ESTABLISHMENT OF PERFORMANCE CRITERIA
STANDARDS
• Develop & Monitor Standards
• Certify Testing Labs
C. CONDUCT OF DEMONSTRATIONS
• Subsystem, Site Selection
• Maintain Demonstrations
D. DATA COLLECTION
E. MARKET DEVELOPMENT
• Develop.Financial & Consumer Acceptance
Data on Solar Utilization
• Define Analytical Technologies to
Assess Economics of Solar Systems
4. COLLECTION & DISSEMINATION OF INFORMATION
• R&D Information
• Demonstration Information
• Supporting Development Information
5. OTHER ACTIVITIES TO PROMOTE EARLY
COMMERCIALIZATION
A. ENERGY POLICY ANALYSIS
B. SOLAR PROGRAM DEFINITION & ANALYSIS
C. REGULATION & INCENTIVES
• Utility Regulations
• Configuration Standards
• Building Codes
• Environmental Alternatives
D. INTERNATIONAL ACTIVITES
ERDA
ERDA
ERDA
ERDA
ERDA/HUD"
FEA,ERDA0
ERDA/HUD JOINTLY7
ERDA, HUD, FEA8
ERDA
HUD, NASA. FEA, DOD,
NSF, GSA, NBS, USDA,
USPS, DOI, HEW
HUD, NASA, DOD, GSA,
USDA, USPS, DOI, HEW
HUD, NASA, FEA, DOD,
GSA, NBS, USDA, USPS,
DOI, HEW
HUD, FEA, DOD, GSA,
USDA, USPS, DOI, HEW
All Federal Agencies
Doing R&D
HUD, DOD, NSF
All Agencies Planning
Construction
NASA, DOD. NSF, GSA,
NBS, EPA, AID
HUD, NASA, FEA, DOD,
NSF, GSA, NBS, AID
ERDA has overall responsibility for this task and shares lead responsibility with HUD in disseminating information from
the residential demonstration program. HUD is lead agency in relaying information to the building industry.
a
FEA is lead agency in analyzing national energy policy as it relates to solar energy; ERDA is lead agency in removing
constraints to commercialization and in defining the economics of alternative incentives to commercialization.
The expanding of the existing program to equip Federal buildings with solar systems is a joint responsibility among
ERDA, DoD and GSA.
Q
ERDA is responsible for truth in energy labeling; HUD for communication standards and building codes; FEA for utility
regulations.
Source: ERDA 23A
42
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A total of 2,000 residential and 400 commercial build-
ing demonstrations are planned by 1979. The specific loca-
tions of these demonstration projects have not yet been de-
fined. However, they probably will be located throughout
all regions of the country. The proposed schedule for the
demonstration program calls for construction to begin during
1976 and continue until 1979; from 1979 to 1985, the instal-
lations will be demonstrated and operated.
The responsibilities of Federal agencies in the solar
heating and cooling program, and specifically in the demon-
stration programs, was included in Tables 7 and 8 given
previously. In the following section, the role of each
agency in the demonstration program is discussed in more de-
tail.
ERDA. In addition to being the primary agency man-
aging the Solar Energy RD&D Program, ERDA also has
the lead responsibility for implementing the com-
mercial segment of the demonstration program, as
well as coordinating the efforts of other agencies
who also participate in this program. Though some
statutory responsibilities do exist, a detailed
management plan assigning various agency responsi-
bilities for specific areas within this program has
not yet been defined.
HUD. The Department of Housing and Urban Develop-
ment has joint responsibility with ERDA for manag-
ing the residential demonstration program. This
portion of the program includes demonstrating solar
space heating, domestic hot water solar systems,
and combined solar heating and cooling systems to
be used in residential buildings. HUD has the re-
sponsibility of selecting the specific designs of
solar systems to be constructed and demonstrated.
After defining the structural, geographic, and site
requirements for these systems, HUD selects speci-
fic building designs and arranges for the installa-
tion of these solar systems.
During the course of each demonstration, HUD will
follow the operation of these systems, and through
maintaining close liaison will ensure that perti-
nent technical information is disseminated to other
participants of this program.
*Assuming that the level 3 program defined in ERDA 23A is implemented,
43
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NSF. Until ERDA was established, the National
Science Foundation was the lead agency for solar
energy research. NSF has funded several demonstra-
tion projects. These include demonstrations by
academic institutions and private corporations, as
well as a special school heating and cooling demon-
stration program. NSF's active participation in
solar demonstrations will be limited to these proj-
ects.
Colorado State University has received NSF funding
for solar home heating and cooling demonstrations.
The university's 3,000 square foot floor area, two-
story house with solar space heating, hot water
heating and lithium-bromide absorption cooling has
been in operation for about two years.
The Phoenix Corporation of Colorado Springs, Colo-
rado, has received NSF funding to construct and test
a solar-heated home. The solar-assisted heat pump
concept is being demonstrated in this experiment
and optimum operating specifications developed.
NSF also funded five solar demonstration projects
located in public schools in:
Warrenton, Virginia, built by Intertechnology
Corporation
Timonium, Maryland, built by AAI Corporation
Minneapolis, Minnesota, built by Honeywell
Corporation
Boston, Massachusetts, built by General Elec-
tric
Atlanta, Georgia, built by Westinghouse and
Burt, Hill & Associates.
These demonstration systems have been in operation
for at least a year and are developing operating
data for system optimization.
NBS. The National Bureau of Standards has a dem-
onstration house with solar heating and cooling
located at their Gaithersburg headquarters. NBS
is testing components and system operations and
developing performance standards in cooperation
44
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with HUD and several private standard-setting
organizations. Interim performance standards have
already been developed which will be used by HUD
in the nationwide residential demonstration pro-
gram.
DOD. The Department of Defense is planning several
solar energy demonstration projects on their facil-
ities around the country. Fifty residential solar
heating and hot water heating demonstrations will
be conducted during 1976 at Army, Navy and Air
Force bases in different parts of the country, in-
cluding Fort Polk, Louisiana; Fort Bragg, North
Carolina; and Fort Belvoir, Virginia. A total of
35 new solar homes will be constructed and 15
houses will be retrofitted with solar systems.
Other DOD demonstrations include:
A solar building at'the Air Force Academy in
Colorado Springs already in operation.
A planned complex of buildings to be heated
and cooled by solar energy at Fort Carson.
Two Army-Air Force exchange buildings (50,000
square feet) at Kirkland Air Force Base in
Albuquerque, New Mexico, and Randolph Air
Force Base, Texas. These are projected for
design during 1977-1978.
Several hot water heating demonstrations.
A battalion headquarters classroom building
at Fort Hood, Texas, scheduled for completion
by August 1976. ERDA funds are supplementing
military construction funds for this project.
A $700,000 project for fiscal year 1976 to
heat and cool 18 classrooms, an auditorium
and a library at Fort Wachuka.
A conceptual design for a solar heated and
cooled 80,000 ft.2 two-story range operations
center at Yuma, Arizona, is being developed.
ERDA funds will be sought for the solar sys-
tem. If these funds do not become available,
the building will be designed for possible
solar retrofitting in the future.
45
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The Army Reserves are conducting cost analy-
ses of solar retrofitting of buildings at re-
serve training centers in Albuquerque, New
Mexico; Seagoville, Texas; and Greenville,
Mississippi.
GSA. The General Services Administration is spon-
soring two solar projects.
A seven-story office building in Manchester,
New Hampshire
A one-story office in Saginaw, Michigan.
Both are heating and cooling projects. The Man-
chester building will be operational by mid-1976;
the Saginaw building by November 1976.
GSA is also developing energy conservation guide-
lines for Federal government buildings and planning
feasibility studies of retrofitting government of-
fices with solar systems.
USPS. ERDA is funding a solar heating and cooling
demonstration at a 29,000 ft.2 post office in
Boulder, Colorado. This is expected to be opera-
tional in 1978. The Postal Service is funding its
own solar demonstration at its 6,000 ft.2 office
building at Ridley Park, Pennsylvania. This sys-
tem has been operational since September 1975.
4. THE ROLE OF EPA IN SOLAR ENERGY DEVELOPMENT
The charter responsibility of the Environmental Protec-
tion Agency is to develop and enforce standards necessary to
protect human health and the environment. Thus, it is EPA's
responsibility to ensure that the widespread utilization of
solar energy systems will not result in major hazards to
human health or in serious environmental pollution. It is
economically advantageous to eliminate potential environ-
mental problems during the definition and development of a
technology rather than to take remedial action after the
technology is in widespread use. Thus, a comprehensive eval-
uation of all potential environmental aspects of solar energy
technologies will result in a greater spectrum of technologi-
cal options for urban or regional environmental planning.
Consequently, EPA will satisfy its charter responsi-
bility by encouraging the development of solar technologies
46
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which.are environmentally acceptable with respect to EPA
standards and guidelines. This objective will be achieved
through consultation with participating agencies during all
phases of technology development. This interagency coopera-
tion will guarantee that environmental considerations are
addressed at the earliest point in the development process.
This will minimize the necessity of promulgating regulations
to correct environmental problems subsequent to widespread
utilization of solar systems. Table 9 presents several
environmental goals toward which the development of solar
technology should be directed. For these goals to be
achieved, EPA should be involved in consultations with the
agency or organization sponsoring research or development.
5. FEDERAL AGENCIES CONCERNED WITH ENVIRONMENTAL IMPACTS
OF SOLAR HEATING AND COOLING SYSTEMS
A number of Federal agencies are responsible for iden-
tifying and mitigating the environmental impacts resulting
from solar heating and cooling systems. As stated previously,
EPA's general responsibility is to develop and enforce stan-
dards, as required/ to protect human health and the environ-
ment. During the heating and cooling demonstration programs,
EPA will assist ERDA as follows:
To provide consultation services to ERDA in prepa-
ration of environmental assessments and environ-
mental impact statements for the residential dem-
onstration program
To assist ERDA in evaluating environmental assess-
ments prepared by contractors for the commercial
demonstration program, and to assist in preparation
of environmental impact statements
To monitor the plans and construction of ERDA's
demonstration program and perform environmental
studies of alternatives to the demonstration pro-
gram aimed at reducing any undesirable impacts.
During the solar heating and cooling demonstration pro-
gram, the Council on Environmental Quality (CEQ) is responsible
There are currently no Federal or local environmental standards
concerning pollution resulting from utilization of solar heating
and cooling systems.
47
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Table 9 *
Appropriate Agency Consultation With EPA During Solar Energy
Research and Development
Solar Energy Related Environmental Goals
Consulting Agencies
*>.
oo
• Equipment should contain minimum amounts of materials whose production
has significant environmental impacts
• Equipment designs should avoid using scarce or depletable materials, or
materials for which the production is energy-intensive
• Recyclable materials should be used when possible in equipment construction
• Toxic working fluids and materials should not be used in case of accidental
release or prolonged exposure
• Institutional and legal barriers, such as "sun rights", should be considered
during system design and implementation
• Implications of large collector arrays, such as potential climate modifica-
tion, should be considered
• Minimize the potential release of air pollutants such as fluorocarbons
from working fluids
• Coordinate long term regulatory, regional and urban planning policy
related to overall energy and environmental implications of solar energy
utilization
ERDA, FEA, HUD, NBS, NSF
ERDA, FEA. HUD, NBS, NASA
ERDA, FEA. HUD, NBS
ERDA, HUD, NASA, NBS
ERDA, FEA, HUD
ERDA, NOAA
ERDA, NOAA
ERDA, CEQ, FEA, FDC
* Responsibility for EPA energy related environmental and health research and development, as well as
control technology R&D, resides with the Office of Energy, Minerals and Industry of EPA's Office of
Research and Development. Cognizance for R&D activities related to pollution control technology for
solar and advanced systems is delegated to OEMI's Industrial Environmental Research Labs in
Cincinnati, Ohio.
-------
for conducting continual evaluations of the adequacy of en-
vironmental assessments developed during the program. In
the preparation of environmental impact statements for the
commercial demonstrations:
ERDA has lead responsibility
DOD and EPA provide consultation services.
For the environmental impact statements required for the
residential demonstrations:
HUD had lead responsibility
ERDA provides technical support
FEA and EPA provide consultation services.
Based on the results of these environmental impact statements,
alternatives to reduce negative environmental impacts may be
developed by the following agencies:
ERDA and HUD have joint responsibility
NASA, FEA, NSF, and NBS to technical support, and
EPA, DOD, and GSA to provide consultation services.
Since ERDA is managing and coordinating the activities
related to the National Solar Heating and Cooling Program,
ERDA will maintain current information on technical and policy
developments concerning the environmental aspects of solar
technologies. The objectives of this activity at ERDA will
be to:
Identify and project the environmental effects*
of solar technology.
Minimize any adverse effects.
Maintain an information base to formulate and help
substantiate policies aimed at assuring that solar
heating and cooling systems are developed in an en-
vironmentally acceptable manner.
ERDA will keep abreast of developments within other Fed-
eral agencies in the area of solar heating and cooling and
will seek to identify and report on any predicted environmental
Environmental effects of solar energy utilization have not yet
been studied in detail and there does not exist any national pro-
gram yet to do this.
49
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consequences. Early and continuous involvement of ERDA with
EPA and CEQ is necessary to ensure that the environmental
impacts identified in Chapter I, and others which emerge over
time, are considered as solar energy technologies are devel-
oped and commercialized.
It is advantageous to address environmental considera-
tions as early as possible in the development of a tech-
nology. It has been emphasized in the previous discussion
that appropriate federal coordination is necessary for the
environmentally acceptable development of solar heating and
cooling technologies. The following chapter presents a
methodology for evaluating the impacts of solar system appli-
cation on air quality in a specific geographical area. This
example is intended to illustrate the kind of continuing
analysis that should be conducted to investigate environ-
mental costs and benefits of solar technology as it develops.
50
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III. ASSESSMENT OF AIR QUALITY IMPACTS OF
SOLAR HEATING AND COOLING SYSTEMS
-------
III. ASSESSMENT OF AIR QUALITY IMPACTS OF
SOLAR HEATING AND COOLING SYSTEMS
As discussed in Chapter I, solar heating and cooling
systems will have a direct effect on two sources of air
pollution emissions:
A decrease in fuel combustion for space condition-
ing and hot water
An increase in the production of materials from
which solar system components are fabricated.
This chapter addresses the decrease in emissions in
urban areas due to savings of local combustion of fossil
fuels and electricity produced at central power plants.
The potential increase in emissions, related to increased
production of materials, in most cases will not occur in
those urban areas where the solar systems are used. Con-
sequently, the assessment of air quality impacts in urban
areas, presented in this chapter, does not include those
industrial emissions.
The assessment of air quality impacts is presented in
five sections:
The fuel savings from solar heating and cooling
systems.This section describes all the factors
which influence the potential fuel savings result-
ing from the use of solar systems. Mathematical
relationships are developed which define the aver-
age energy load for various building types, the
potential, per-building fuel savings due to solar
systems, the number of buildings which may be
equipped with solar systems, and total areawide
fuel savings. The equations presented in this
section form a mathematical model for projecting
the fuel savings due to solar heating and cooling
systems for any urban area, as a function of the
rate of acceptance of solar systems in that area.
A glossary of terms is provided at the end of this
chapter to serve as a guide for understanding the
relationships developed in the chapter. Additional
input data required for the model are also given in
51
-------
this section. These data were taken from several
sources; primarily the Phase "O" solar heating and
cooling study funded by the National Science Foun-
dation (NSF).*
Changes in pollutant concentrations due to reduced
fuel combustion. This section discusses the changes
in emissions and ambient air quality which may re-
sult from solar-induced fuel savings.
Summary of the methodology. The terminology and
key equations defined in the two previous sections
are summarized in this section.
Sample application of the methodology. In this
section, actual data for the Baltimore, Maryland
SMSA, and postulated values for key input param-
eters are combined to demonstrate how the method-
ology can be used to forecast changes in annual
emissions.
Parametric analysis of regional emission savings.
A key feature of the methodology is that it can be
used for parametric analyses. In this section that
feature is demonstrated by simplifying the equations
to express emission changes as a direct function of
only one parameter (rate of market penetration).
From the simplified equations emission forecasts
corresponding to several assumed market penetration
rates are then developed for a hypothetical urban area,
1. THE FUEL SAVINGS FROM SOLAR HEATING AND COOLING SYSTEMS
The development of mathematical relationships for esti-
mating the potential fuel savings due to solar energy utiliza-
tion is presented in six sections:
Definition of climatic regions and building cate-
gories
General Electric, Solar Heating and Cooling of Buildings,
Phase "0", Feasibility and Planning Study Final Report, May 1974,
(hereafter cited as GE Phase "0" Report). This major study was
directed toward assessing the feasibility of solar heating and
cooling systems and planning for proof-of-concept experiments.
52
-------
Energy load for each building type
Potential energy savings per building
Potential fuel savings per building
Number of buildings equipped with solar systems
Areawide fuel savings.
(1) Definition of Climatic Regions and Building
Categories
The fuel or energy displaced by solar systems will
be either fossil fuels burned on site, or electricity
generated at a central station/ or both. The potential
fuel savings are based on:
The energy requirements for residential and
commercial buildings
The portion of the energy load supplied by
the solar system, and the fuel displaced
The number of buildings equipped with solar
systems.
Each of the above considerations are regional in
nature; varying with climate, insolation levels, and
the many factors influencing the commercial acceptance
of solar systems. In addition, energy load and fuel
savings will vary with building type, because different
building types correspond to different heating/cooling
demands, construction, and usage.
In order to facilitate the analysis of energy
savings and air pollution impacts, generalizations
concerning building variations and regional climatic
factors may be made. If it is assumed that climatic
conditions are approximately uniform over certain
regions of the country, then the Continental United
States may be divided into general climatic regions.
If it is also assumed that on the basis of energy char-
acteristics, residential and commercial buildings may
be classified into representative building categories,
then the heating and cooling loads for typical buildings,
representative of all buildings of that category, may
be defined. It should be clear that there may be
53
-------
significant climatic variation within regions, and that
a significant amount of detail is lost by generalizing
about building types and regional climatic conditions;
the generalizations are used to simplify the analysis.
A climatological regionalization scheme is shown
in Figure 1, where each of the 12 climatic regions
is designated by a city where the climate is represen-
tative of the region. Climatic data for each city are
given in Table 10. Characteristics for 17 general
building types are given in Table 11. These charac-
teristics may be used to define energy demands for
the buildings of each category. The criteria used to
define building types were that the categories reflect
buildings in place or to be constructed in large vol-
ume, and the building characteristics and uses be rep-
resentative.
UMID CONTDCNTAl
WARM SUMMER
Source: GE Phase "0" Report (May 1974).
FIGURE 7
Regional Climatic Classification
(2) Energy Load for Each Building Type
There are three components of the energy load of
a building which are under consideration here: space
heating, space cooling, and domestic hot water. For
54
-------
Table 10
Climatic Data for Sample Cities
en
Location
Madison
Charleston
UA.
Boston
D.C.
Phoenix
Miami
Omaha
Bismarck
Nashville
Seattle
ft. Worth
Winter Design
Temp. ~°Cl
-20.5
- 1.1
6.6
-12.2
- 12
1.1
8.8
-18.3
-28.3
- 8.8
0.0
- 4.4
Summer Dry
Bulb Temp. ~°C2
31.1
33.8
32.2
31.1
33.3
41.1
31.6
34.4
32.7
35.0
26.1
37.7
Insolation
(Langley/hour)
50.0
52.0
58.1
46.2
53.6
65.8
53.0
53.9
55.6
51.9
52.0
62.3
Design Relative
Humidity (%)
52
64
49
55
53
31
65
50
48
53
62
48
1 ASH RAE 97-14% values.
2 ASH RAE 2-%% values.
Source: GE Phase "0" Report.
-------
Table 11
Characteristics of Typical Buildings
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
IS
16
17
Building Type
Description
Residential, Single Family
Residential, Multiple High Rise
Residential, Multiple Low Rise
Hotel/Motel, High Rise
Hotel/Motel, Low Rise
Office Building, High Rise
Office Building, Low Rise
Warehouse
Industrial, Light Process Load
Industrial, Heavy Process Load
Educational, K to 12
College/University
Auditoriums
Health Care, Clinic
Hospital
Retail, Merchandise Mall
Retail, Individual Store
Number
of
Stories
2 + B
14
3
14
2
30
2
1
1
1
1
2
1 + B
2
4
1
1
Floor Area
Per
Story
900
10,350
200
10,350
20,000
20,000
10,000
60,000
100,000
200,000
52,000
25,000
22.000
4.500
12,000
750,000
5.200
Total
Sq, Ft.
1,800+B
145,000
21,600
145,000
40,000
600,000
20,000
60,000
100,000
200,000
52,000
50,000
30,000
9.000
48.000
750.000
5.200
Wall
Area
Sq.Ft.
2,196
51,156
12,700
51.156
10,800
216,000
8.800
25,000
28,000
43,200
12,880
16,900
15,500
7.280
23.200
99,000
5,440
Window Area
Kof
Wall
15
20
20
20
30
30
20
0
5
0
25
25
0
10
20
5
20
Total
Sq. Ft.
330
10,231
2,550
10,231
3,240
64300
1,760
0
1,400
0
3,200
4,225
0
728
4,640
4^50
1,088
Height/
Story,
Ft.
9
9
9
9
9
12
11
25
20
24
14
13
25
13
13
18
16
Volume. Cu. Ft.
Abow
Ground
16,200
1, 305,000
79,400
1,305.000
360,000
7.200.000
220,000
1,500,000
2,000,000
4,800.000
728,000
650,000
550.000
117.000
624.000
13,500,000
83,200
Below
Ground
B
O
0
0
O
O
O
O
O
0
O
O
80.000
O
O
O
O
Infiltration/
Ventilation
Requirements
CFM/sq. ft. floor
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.50
1.50
2.00
0.75
0.75
0.75
0.75
1.00
0,50
050
1 a-0.305m
Source: GE Phase "O" Report (adapted from data supplied by the Ballinger Co.)
-------
a given building type, the thermal load for each of
these three components, regardless of fuel supply, is
a function of:
Building shape and dimensions
Construction (materials)
Insulation
Fenestration
Use patterns
Internal loads*
Climate (degree-days, peak heating/cooling
loads, wind, humidity)
Ventilation requirements.
Estimates of the energy demand B. (in Btu) for
each building type j and application m (heating, cool-
ing, hot water) in each region are given in Tables 12:
and 13.T
The data in Table 12 are based on an hour-by-
hour simulation of heating and cooling loads which in-
cluded the following parameters:
Size, shape, construction, and orientation
of each "typical" building
Ambient wind, insolation, and temperature
Transient electrical loads
Infiltration loads
Heat generated within the building by lights, appliances, and
occupants.
Source: The data presented in Tables 12 and 13 are the mosti
current estimates of energy loads (by type of building) for repre-
sentative cities in each climatic region of the country. These
data, based on energy loads originally presented in the GE Phase "<
Report, were updated with the assistance of GE, to provide the besi
possible data base for this assessment.
57
-------
Table 12
Heating and Cooling Loads, B.
(106 Btu/Year)
Location
Madison
ChariKton
UA.
Boston
D.C.
Phoenix
Miami
Omaha
Bi&marck
Nashville
Seattle
Ft. Worth
Cooling Load By Building Type
1
20
88
8
20
33
158
233
35
15
101
9
150
2
3,289
19,536
2.063
3,244
5,4t2
19.662
45,633
8,881
2,314
18,927
1,530
22,368
3
1,417
7.375
1,254
1,164
1.870
8.072
16,958
3,368
871
2,730
929
9,002
4
8,595
51,567
5,689
8,497
14,286
52,032
120.564
23,576
6,271
50,069
3.948
58,891
5
328
3.7B5
160
399
719
6,231
11,224
1,598
519
1,198
759
5,562
6
18,005
67.835
27.592
20,077
25,179
72,162
135,275
36,270
14,293
62.063
12.241
73,603
7
730
2,090
1,114
720
792
2,678
4.277
1,166
542
1,329
451
2,456
8
-
-
• -
-
-
-
-
-
-
-
-
-
9
-
-
-
-
-
-
-
-
-
-
-
-
10
-
-
-
-
-
-
-
-
-
-
-
-
11
1,758
6,786
1,486
1,383
1,900
5,312
14.244
3,193
1,680
2.973
1.228
6,876
12
2,017
7511
2,507
1390
2,624
6379
16.054
3,891
1,409
8,932
1,178
8,117
13
405
2341
40
364
769
2.334
6,570
1,349
283
3,143
121
3,616
14
232
1,101
243
232
336
927
2.306
510
162
1.008
127
1,147
15
3,376
10394
4341
4,594
4,102
10,290
21,078
5307
2,407
9363
2,159
11,053
16
46396
163,278
66,307
47365
59,000
151 339
223352
84379
33365
146,184
29,554
167383
17
193
771
235
193
257
739
1322
386
137
715
112
819
Ol
00
Source: Update of data presented in Solar Heating and Cooling Buildings Phase "O" Report by GE to NSF. May 1974.
Notes:
1. Design conditions: Winter indoor design temperature: 70° F (21° C) daytime; 65° F {18.3° C) nighttime
Summer indoor design temperature: 78° F (25.5° C) dry bulb at 50 percent relative humidity
Climatic conditions: NOAA observed dimatological data for one year man-hourly basis.
3. Note that the decree-days for the "typical" year for which NOAA data were used deviated from 30-year*avarages
by as much as 28 percent.
4. The calculations are consistent with the methods and data given in the ASHR AE Handbook of Fundamentals.
•Building types defined in Table 13.
2. Model used for hourly toad simulation: GE Building Transient Thermal Load program.
-------
Table 12
(Continued)
Location
MM won
Ctwteun
LA.
Bonon
ac.
Phoenix
Miami
Omaha
Bi«n»rck
Mgptfujl|«
Send*
Ft. Worth
HMtin« Lo«l By BuMhi* TVM
1
16t
70
48
139
. '«
42
5
148
193
85
108
76
2
8,102
3.571
1.728
6.696
6.083
1.499
143
6,480
9,721
5.506
7,032
3,104
3
11.022
3.189
1.700
9.088
7,540
1312
645
9,029
11.J40
4.280
6.391
3,752
4
73,764
32,693
15328
60,088
56,407
13399
1.173
69,040
88.592
50.129
63.793
28257
5
4,973
447
422
3,633
3,090
1326
121
3,786
5,976
2.378
3361
845
6
2.824
254
240
2,061
1,755
584
63
2,139
3,394
1,361
2,022
478
7
1,479
353
219
1,137
931
126
6
1,186
1,776
713
1,076
411
8
9.867
5,470
3.983
8,128
8,290
3316
270
8,236
18,112
6,281
11X129
3375
9
41365
17375
10,445
34,010
30,300
10.923
718
34.641
50,917
26,111
30^46
15A89
10
106,730
43,148
32.793
86,646
88,137
25.937
1328
88,300
131,449
67.160
77,889
40J21
11
11^08
6,722
3,151
9,320
8^80
2363
SO
9.364
13^30
7^18
9.784
4,146
12
9,363
2,156
1^82
7,208
6,782
2.133
83
7^62
11,376
4398
8.700
Z.720
13
5,460
2^58
972
4^64
4,180
759
106
4,443
6329
3325
4333
2.129
14
2,071
731
377
1360
1^40
410
165
1.673
2^82
1^74
1384
709
IS
9,403
1/»7
368
6,755
3377
654
56
7345
11307
3,168
6,361
1,728
16
86305
18,764
9365
66,540
60300
21259
717
713»
106379
39,402
57/411
23.261
17
1,127
196
150
878
786
133
2
913
1362
601
751
370
Oi
•Sulking tNM
-------
Table 13
Hot Water Loads/ B.
j Building Type (j) Description
1 Residential, Single Family
2 Residential, Multiple High Rise
3 Residential, Multiple Low Rise
4 Hotel/Motel, High Rise
5 Hotel/Motel, Low Rise
6 Office Building, High Rise
7 Office Building, Low Rise
8 Warehouse
9 Industrial, Light Process Load
10 Industrial, Heavy Process Load
11 Educational, K to 12
12 College/University
13 Auditoriums
14 Health Care, Clinic
15 Hospital
16 Retail, Merchandise Mall
17 Retail, Individual Store
Average
Annual Energy
Demand (106 Btu)
13.3
1,253
265
465
218
569
19
4
133
266
95
142
47
57
1,490
19
2
Average Daily Water
Demand {Gallons)
45
4,100
900
2,000
1.000
3,000
100
20
730
1,040
500
750
250
200
5,250
100
10
Typical Hot Water
Temperature, °F
(°C in Parenthesis)
150(65.5)
150(65.5)
150 (65.5)
130(54.0)
130(54.0)
120(49.0)
120 (49.0)
115(46.0)
115(46.0)
115(46.0)
115(46.0)
120 (49.0)
120 (49.0)
145 (63.0)
145 (63.0)
115(46.0)
115(46.0)
Source: GE Phase "0" Report.
Note: (1) Based on average water temperature of 50P F (10° C).
(2) Process hot water not included.
-------
Personnel loads
Thermostat settings.
Detailed computer* analyses were performed by
General Electric for six buildings in nine locations
(54 total combinations). The values for the other 150
combinations in the table are based on less detailed
load calculations, adjusted to reflect the results of
the detailed simulations.
The hot water loads in Table .13 are representative
for the average building types defined previously.
It is assumed that the loads are independent of geo-
graphy. Note that the energy requirement depends on
the input and delivered temperature, a-s well as the
quality/ of hot water.
(3) Potential Energy Savings Per Building
The maximum amount of energy per square meter
which in theory could be used for heating and cooling
is limited by latitude and several atmospheric condi-
tions, primarily cloud cover and atmospheric clarity.
For a given density of collectable solar energy, there
are several factors which determine the thermal capac-
ity of a solar system. The single most expensive com-
ponent of a solar system which limits the system's
thermal capacity is the collector. Consequently, be-
cause of cost considerations, physical limits on the
space available for solar collectors, and the necessity
for designing heating/cooling system capacities for
peak requirements, solar systems are ordinarily de-
signed to provide less than 100 percent of a building's
energy load.
The life-cycle economic optimization of a solar
heating and cooling system involves trading-off several
design parameters including:
The type of application (space heating, space
cooling, hot water, or a combination) for
Building Transient Thermal Load (BTTL) computer program prepared
by General Electric and reported in Solar Heating and Cooling of
Buildings, Phase "0" Report, May 1974.
61
-------
which the solar system was designed to supply
energy.
Type of system components used: trade offs
usually involve working fluids, thermal stor-
age systems, and heat exchangers or pumps.
Performance criteria and materials for se-
lected components. Parameters which have the
highest cost impact are collector area and
collection efficiency and thermal storage
capacity.
System reliability and maintenance require-
ments .
Life-cycle cost optimization also involves the cost of
competing fuels and the period over which costs are to
be amortized (which may be less than the solar equip-
ment lifetime) .
Minimization of solar equipment costs and maxi-
mizing economic benefit usually results in systems
which are designed to provide approximately 30 percent
to 70 percent of heating and cooling requirements.
This means that conventional heating and cooling equip-
ment must be installed in addition to the solar system,
although perhaps at reduced capacity.
The portion of building energy load supplied by
solar systems of optimized design, therefore, will
vary with region and with building type. If the per-
centage of the load for each building type j and appli-
cation m which is supplied by solar energy is P-_*
(where 0 s; P. s 1.0), then the potential energy sav-
ings per building (in Btu) is given by:
Ejm = Bjm x Fjm (1)
Note that the total energy per building supplied by
solar energy is given by: E. .
m
Typical values for F . by building type and loca
tion are given in Tables 14 and 15 for space heating
and cooling. These data reflect hour-by-hour sim-
ulations of solar performance, and assume a heat
62
-------
Table 14
Energy Savings, Space Heating, and Hot Water (F. )
(Fraction of Total Load) D
Space Heating
en
U)
Location
Madison
Charleston
L.A.
Boston
D.C.
Phoenix
Miami
Omaha
Bismarck
Nashville
Seattle
Ft. Worth
Building Types
1
.32
.72
.99
.39
.46
1.00
1.00
.33
.46
.42
.36
.69
2
.08
.15
.47
.12
.12
.39
1.00
.11
.11
.07
.07
.15
3
,31
.65
1.00
.42
.47
.98
1.00
.37
.31
.34
.26
.58
4 1 5
.08
.15
.47
.12
.12
.39
1.00
.11
.11
.07
.07
.15
.37
.95
.43
.49
.54
.92
1.00
.43
.53
.43
.33
.85
6
.07
.10
.21
.07
.08
.13
1.00
.07
.11
.03
.05
.07
7
.36
.75
1.00
.47
.53
1.00
1.00
.40
.30
.34
.20
.67
8
•41
.53
.81
.48
.49
.82
1.00
.45
.41
.31
.26
.61
9
.23
.38
.72
.28
.33
.62
1.00
.26
.18
.19
.17
.38
10
.19
.34
.60
.23
.25
.58
1.00
.21
.18
.15
.18
.31
11
.38
.48
.92
.47
.49
.86
1.00
.56
.31
.28
.18
.59
12
.25
.62
.93
.34
.41
.72
1.00
.21
.34
.21
.24
.50
13
.25
.46
.89
.31
.35
.87
1.00
.28
.34
.20
.28
.40
14
.22
.42
.85
.28
.32
.69
1.00
.24
.30
.19
.26
.40
15
.14
.62
1.00
.18
.32
.86
1.00
.16
.18
.13
.16
.41
16
.53
.85
1.00
.62
.72
1.00
1.00
.59
.77
.32
.65
.79
17
.41
.80
1.00
.50
.54
1.00
1.00
.45
.33
.31
.15
.67
Source: GE Phase "O" Report.
Hot Water
A representative estimate for the fraction of total hot water load supplied by solar systems is 0.9 for all building types. Specific values depend on a number of system design
parameters and patterns of demand.
-------
Table 15
Energy Savings, Space Cooling,
(Fraction of Total Load)
.
J
a\
*>.
Location
Madison
Charleston
L.A.
Boston
D.C.
Phoenix
Miami
Omaha
Bismarck
Nashville
Seattle
Ft. Worth
Building Types
1
.96
.77
.89
.98
.72
.83
.83
.90
.97
.96
.85
.90
2
.27
.06
.70
.18
.15
.14
.04
.10
.57
.07
.53
.07
3
.61
.34
.77
.65
.55
.59
.24
.53
.77
.70
.75
.67
4
.27
.06
.70
.18
.15
.14
.04
.10
.57
.07
.53
.07
5
.96
.45
.88
.80
.70
.63
.30
.52
.97
.55
.75
.52
6
.06
.03
.03
.05
.03
.03
.02
.03
.10
.03
.10
.03
7
.52
.34
.55
.60
.43
.53
.26
.45
.78
.43
.65
.41
8-11»
-
-
-
-
-
-
-
-
-
-
-
-
12
.31
.11
.37
.31
.19
.26
.08
.17
.60
.15
.50
.15
13
.65
.30
.88
.60
.46
.63
.20
.44
.97
.33
.75
.32
14
.40
.14
.70
.38
.25
.32
.10
.22
.69
.30
.60
.30
15
.07
.04
.08
.08
.07
.08
.03
.04
.21
.05
.17
.05
16
.50
.35
.57
.55
.38
.55
.30
.60
.80
.37
.65
.38
17
.54
.30
.64
.60
.42
.58
.22
.43
.88
.39
.70
.39
'Building types 8-11 are not normally cooled.
Source: GE Phase "O" Report.
-------
exchange system for heating, an absorption air condi-
tioner for cooling, and a collector area equal to 50
percent of the roof area (the maximum for a peaked
roof).
(4) Potential Fuel Savings Per Building
In order to identify the quantity of each fuel
saved, the fuels which would have been burned in each
individual building in the absence of the solar system
must be identified, and the portion of the heating,
cooling and hot water demand supplied by solar energy
in each individual building must be determined. De-
for a11 n^w build-
fine the fuel use factor FFNjkm(T)
ings of type j as the fraction of the load for each
application m which is supplied by fuel k* in year T.
Then:
£ FFNjkm
(when j and m are constant) (2)
For each building type j and year T the fuel use
factors FFN..W form a matrix as follows:
jkm
FUEL (k)*
Application (m)
Heating
Cooling
Hot Water
Elec.
Dist.
Oil
Resid.
Oil
Nat.
Gas
Coal
Other
All factors are less than unity, and the sum of all
rows equals one.
On site (end use) consumption.
65
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Since the fuel use factors are time-dependent,
the factors for a given building type for space heating
when plotted graphically, might appear as follows:
o
Z £5
O H
H CO
ft O
tf
2
H
3 **
ggS
en
1.0"
ELECTRICITY
Fuel savings depends upon the efficiency of the
furnace, air conditioning system and hot water heater.
Define HE, as the efficiency for fuel k and application
m; typical values for HE, are given in Table 16.
Table 16
Typical Heating/Cooling Equipment Performance (HE, )
Heating Equipment Efficiency
Application (m)
Space Heating
Hot Water
Electric! tyt
1.00
0.60
Fuel (k)
Natural Gas
0.65
0.60
Heating Oil
0.60
_
'Defined as (Btu supplied)/(Btu of fuel input).
tExcluding power plant generating efficiency (i.e., (Btu supplied)/(Btu of electricity used).
Cooling Equipment Coefficient of Performance*
Application (m)
Space Cooling
Fuel (k)
Electricity
Natural Gas
Heating Oil
2.50
0.60
'Defined as (Btu removed)/(Btu of fuel input).
66
-------
The annual per-building savings of fuel k is then
given by:
":* = £
where Ck is the Btu content of the fuel (Btu per unit
fuel); E. was defined by equation (1).
(5) Number of Buildings Equipped With Solar Systems
The number of buildings in which solar heating and
cooling systems will be installed depends on how many
buildings of each type are heated and cooled by con-
ventional means and on the rate of market acceptance
of solar systems. The percentage of buildings which
are heated and cooled depends on climatic conditions.
The extent and rate at which solar systems pene-
trate the heating and cooling market will vary geo-
graphically and depends on several factors. The most
important factor is probably cost. Though operating
costs are lower than for conventional systems, solar
systems have a higher initial cost. Thus, most solar
applications are economically attractive only when
life-cycle costs are considered. The most important
cost factor for conventional systems in a life-cycle
cost comparison is the cost (and availability) of con-
ventional fuels. The economic attractiveness of solar
systems, therefore, depends primarily on the initial
cost of the solar system, the cost of competing fuels,
and the willingness of the consumer to base decisions
on life-cycle, rather than initial, costs.
There are additional cost considerations which
affect market acceptance. Because solar technology
has not gained widespread acceptance, the maintenance,
repair, and operating costs are not well established
historically and are considered by many consumers to
be high. The life-cycle cost argument is based on
future fuel prices, which can be estimated but not
guaranteed. The risks associated with solar systems
influence economic considerations, specifically in-
surance, financing, and resale value.
Several other barriers to market acceptance will
affect market penetration. There are currently no
67
-------
standards of performance, quality, or safety for solar
systems. Thus, poor quality equipment might be intro-
duced in the market and damage consumer confidence.
Although several companies with significant investment
capital resources are entering the solar equipment mar-
ket actively, it is expected that mass production of
solar components will not begin until the market matures
considerably. Hence, costs will remain high due to
piecework production.
There are social barriers to acceptance, such as
public confidence in the technology and in the solar
industry. There is a general lack of awareness of
solar system capabilities and limitations among manu-
facturers and the public, many of whom question the
performance of solar systems. Existing solar demon-
stration houses are considered by many to be aestheti-
cally unappealing, a fact which adds to the unwilling-
ness of a larger portion of the public to invest in
solar systems.
One important factor influencing the rate of ac-
ceptance of solar systems will be the enactment of
various types of incentives to encourage the utiliza-
tion of solar technologies. Incentive programs pro-
posed to stimulate the solar energy market may be cate-
gorized into five general groups:
Tax incentives; income, sales, property,
or usage taxes
Finance incentives: loans and bonds
Utility rate restructuring
Grants or subsidies for consumers and
manufacturers
Information and demonstration programs.
Of the state or local incentives proposed or al-
ready enacted, property tax incentives have received
the greatest attention. Eight states have passed
property tax exemptions and at least 21 are consider-
ing property tax proposals. How actively Federal,
state, and local governments establish incentive pro-
grams will have a direct impact on the rate of utili-
zation of solar technology.
68
-------
The remainder of this subsection is devoted to de-
velopment of a method to forecast the number of buildings
equipped with solar systems. This method is based on
parameterization of the rate of market penetration of
solar systems.
The stock of buildings at any time is determined
by the demolition rate and the rate of new construction.
These rates may be expressed as the percentage of exist-
ing buildings which were demolished or built per unit
time. In other words, if in a given period of time
AT (e.g., a year), AN buildings were demolished, and
the total number of buildings at some point during the
period was N, then the demolition rate is equivalent to
i * (percent per unit time) . A similar approach
may be used to define the rate of new construction.
Using d.(t) as the demolition rate for building type j,
c,(t) as the rate of new construction, and N.(t ) as
the number (stock) of buildings at time t , the total
number of buildings at time t (t > tQ) is given by:
N..(t) = N..(t0) exp I [c..(t) - d..(t)] dt (4)
where [c . (t) - d . (t) ] is the net rate of building stock
change P . (t) .
Discrete values for the functions c . (t) and d.(t)
may be determined from historical data if the number
of new starts or demolitions in a given time period
are known, and the stock of buildings (at the begin-
ning, midpoint or end of each time period) or an average
stock over the time period is known. A curve may be
fitted to the discrete points to produce continuous
functions for c . (t) and d.. (t) .
Solar systems may be either installed in new
buildings or retrofitted into existing buildings. If
the rate at which solar systems are installed in new
buildings is S . (t) the percent of new starts at time t
which are equipped with solar systems, and r.(t) is the
rate of retrofit, then the instantaneous rate at which
69
-------
the number of new solar-equipped buildings is changing
at time t is given by:
= N..(t) x c..(t) x S..(t)
(5)
and the instantaneous rate at which the number of solar
retrofits is changing at time t is given by:
ne.(t) = N.. (t) x r. (t) . (6)
Thus, the number of new solar-equipped buildings built
during the year T will be
NST.(T) = ns.(t) dt (7)
f
JT
and the number of solar retrofits during the year will
be
NET.(T) = I ne.(t) dt (8)
?. (T) = /
J /T
A simple expression for the number of buildings
equipped with solar systems in a given year may be
developed by making a few assumptions. Define G(T )
as a dimensionless areawide growth index for year Tx
(relative to year TQ) for the region under study. If
the following assumptions are made:
The demolition rate d . (t) for all buildings
is assumed to remain constant at 2-1/2 per-
cent per year,* i.e./ d . (t) = d = 0.025.
The change in building stock will approxi-
mately equal the growth index:
N . (T )
-J x
. .
(TQ)
As recommended in the GE Phase "0" Report.
70
-------
The rate of new construction c.(t) will be
approximately constant over time, i.e.,
cj(t) - Oj
then the rate of new construction is approximately
equal to:
In (G (T ))
c. = — _ - -2 — + 0.025 = constant (10)
-
and the net rate of building stock change is approxi-
nately:
In (G (T ))
T
The average number of total buildings existing
years after base year TQ is then:
P.T
N..(T) =: N..(T0) e J (12)
and the average number of new buildings built in year T
is given by:
NS . (T) = c.. x N.. (T)
P.T
= Cj x N_.(To) e D (13)
If S.(T) is the percentage of new buildings which
are equipped with solar systems during year T, then
the number of buildings equipped with solar systems
during the year T* is:
NST.(T) = NSj(T) x Sj(T) (14)
* Note that the cumulative number of buildings equipped with solar
systems by year T is then:
all T j
£ T
71
-------
(6) Areawide Fuel Savings
The number of new buildings built in year T which
are equipped with solar systems is NST.(T), as defined
by equation (14): ^
NST.(T) = NS.(T) x S.(T) (14)
The potential annual per-building fuel savings
(U., ) were defined above in equation (3). The area-
wide savings of fuel k in residential buildings by
year T is then:
X
UTk(V = 2] ]C (sj(T) XNSJ(T) x ujk5 (15)
all T j
s: T residential
X
The areawide savings of fuel k in commercial
buildings by year T is then:
UT^(T ) = V^ y^ (S.(T) xNS.(T) x U..) (16)
*• x t—J t-~t 1 1 JK
all T j
s: T commercial
• The total areawide fuel savings are therefore:
+• r C*
UT, (T ) = UT, (T ) + UT, (T ) (17)
If * «> * 1^ * ^^ * T^ * ^r * * '
Jx A. A. JS. A. Jx
These fuel savings can be translated into air
pollution emissions that would have been generated
had these fuels been burned to satisfy the energy
loads that solar systems may supply. Factors affect-
ing changes in these emission levels are discussed in
the next section.
2. CHANGES IN POLLUTANT CONCENTRATIONS DUE TO REDUCED
FUEL COMBUSTION
As described in the previous section, utilization of
solar energy will produce savings of electricity and fossil
fuels burned directly for space heating and hot water. The
latter will result in reduced residential and commercial
source fuel combustion emissions/ while the former will
72
-------
result in reduced point source emissions from power plants.
Changes in emission rates will produce changes in ambient
pollutant concentrations. In the section below the impact
on air quality from area source emission changes is discussed.
The following section deals with power plant emissions.
(1) Area Source Emissions and Air Quality
The emission inventory of a metropolitan area
contains the location and emission levels for the air
pollution sources in the area. For purposes of pol-
lutant dispersion modeling, emissions from area sources
are represented as emission densities which are uniform
over a given grid area. The least accurate representa-
tion of area source emissions corresponds to a uniform
area source emission density over the entire urban area.
The reliability of pollutant concentration estimates
increases if the urban area can be divided into a large
number of small grids, for which individual emission
densities are calculated.
Gridded area source emissions may be calculated
in one of two ways:
Directly from highly detailed source-emission
data
By allocating aggregated emission levels to
smaller grid areas.
If detailed fuel use and emission data are available for
small gridded areas, the method described in Section 1
of this chapter may be used to estimate the changes to
the emission inventory resulting from the utilization
of solar energy. The more feasible approach, in terms
of data which are ordinarily available, is to use the
method described previously to estimate emissions for
comparatively large areas, and to allocate emissions
to subcounty grids. Several allocation techniques,
including both computerized and manual methods, are
described in the AQMA Guidelines.*
EPA, Guidelines for Air Quality Planning and Analysis, Vol. 8,
("Computer-Assisted Area Source Emissions Gridding Procedure")
and Vol. 13 ("Allocating Projected Emissions to Subcounty Areas.")
73
-------
In either case, the change in emissions for any
grid for pollutant p is given by:
xEF
pk
UTk(Tx)
xEF
pk
and the change in the emission density for any grid
(regardless of grid size) is
x
(19)
when A is the grid area; UT^(T ) and UT°.(T ) are the
K X K. X
residential and commercial fuel savings for fuel k for
sources within the grid; EFr, and EF°, are the resi-
dential and commercial emission factors (Ib of pollut-
ant p per unit fuel k) . Emission factors for the most
common residential and commercial fuels are given in
Table 17.
Table 17
Emission Factors for Common Residential and
Commercial Fuels
Pollutant
Fuel
Residual Oil
Residential
Commercial
Distillate Oil
Residential
Commercial
Natural Gas
TSP
10
23
10
15
19
S0x
1448
1598
144 S
1448
0.6
NOX
12
60
12
60
100
HC
3
3
3
3
8
CO
5
4
5
4
20
Units
lb/103 gal
lb/103gal
lb/103gal
lb/1Q3gal
Ib/106ft3
Note: S is percent sulfur.
74
-------
The change in area source emission densities de-
scribed previously will result in changes in expected
pollutant concentrations. A number of techniques have
been developed to relate pollutant concentrations to
atmospheric conditions and background concentrations.
The choice of appropriate atmospheric dispersion model
depends on the pollutant and averaging times under con-
sideration, the accuracy and detail of the emission in-
ventory, and the availability of meteorological data.
Table 18 shows National Ambient Air Quality Standards
and the averaging times defined for each criteria pol-
lutant.
Table 18
Federal Ambient Air Quality Standards*
Maximum Concentration
Pollutant
Suspended paniculate matter
Sulfur oxides
Carbon monoxide
Photochemical oxidants
Nonmethane hydrocarbons
Averaging
Time
Annual
24 hr
Annual
24 hr
3hr
8hr
1 hr
1 hr
3hr
(6-9 a.m.)
Primary
Standard
75 pg/m3
0.03 ppm
0.14 ppm
9 ppm
35 ppm
0.08 ppm
0.24 ppm
Secondary
Standard
150/ug/m3
0.02 ppm
0.10 ppm
0.5 ppm
9 ppm
35 ppm
0.08 ppm
0.24 ppm
Nitrogen oxides Annual 0.05 ppm 0.05 ppm
Additional standards have been proposed for asbestos, beryllium, mercury, and lead;
they are being prepared for fluorides, poly cyclic organic compounds, odors (including
hydrogen sulfide), chlorine, hydrogen chloride, arsenic, cadmium, copper, manganese,
nickel, vandium, zinc, barium, boron, chromium, selenium, pesticides, radioactive sub-
stances, and aeroallergens.
*40 CFR 50; 36 FR 22384, November 25, 1971; as amended by 38 FR 25678, September 14.
1973, and 40 FR 7042, February 18,1975.
75
-------
A summary of the dispersion models which are the
most widely available to air pollution control agencies
is given in Volume 12 of the AQMA Guidelines, "Applying
Atmospheric Simulation Models to Air Quality Maintenance
Areas." This volume contains information concerning the
general nature, data requirements and level of detail of
several models. Some of the techniques which may be ap-
plied for hand calculation of the area source air quality
impacts of solar heating and cooling systems are shown
in Table 19. These models are described in more de-
tail below.
Table 19
Selected Atmospheric Dispersion Models
for Area Source Emissions
Pollutant Applicable Model
Particulates Hanna-Gifford
Rollback
Sulfur oxides Hanna-Gifford
Rollback
Nitrogen oxides Rollback
Carbon monoxide Rollback
Hydrocarbon/oxidants Appendix J
Rollback
1. Rollback
The rollback model is based on the following
expression relating pollutant concentrations (X)
to emission rates (Q) and background concentration
(b) :
X = kQ + b (20)
This method assumes that the dispersion pa-
rameter k does not vary with time or with source-
receptor relationships, and that emission rates
76
-------
are uniform across the area. Thus the relation-
ship of emissions (Q.) and air quality in a future
year (X. ) to the emissions (Q ) and air quality (X )
in a base year can be expressed by the following
proportionality :
X - b Q
The basic assumption in the model is that a
given percent change in pollutant emissions will
result in a similar change in pollutant concentra-
tions. It is a technique for scaling concentra-
tions up or down to reflect similar changes in the
gross emission rates. The inputs required for this
method are areawide emissions for the base year and
the year of interest, and a pollutant concentra-
tion representative for the area and averaging time
of interest.
2. Appendix J HC-0 Relationship
X
Appendix J of Federal Register 40 CFR Part 51
contains a graphical presentation of the percent
reduction in hydrocarbon (HC) emissions required
to reduce an observed peak hourly average oxidant
(O ) concentration to the National Ambient Air
Quality Standard (NAAQS) for Ox- The relation-
ship assumes that the maximum 1-hour Ox concentra-
tion is directly affected by the quantity of HC
emitted during the morning hours. This assumption
is based on the observed relationship of HC and 0
concentrations. To use this method, emission levels
for the base year and year of interest must be
known.
3. Hanna-Gifford Model
This model is most appropriate for stable
pollutants such as S02, particulates, and CO and
may be used to estimate 1-hour and annual average
concentrations of these pollutants. The model can
be used to estimate an average concentration for
77
-------
any defined area. In the basic Hanna-Gifford
model, the dispersion constant is a function of
stability/ wind speed and the size and number of
area sources. The equation relating concentra-
tions to emissions is
X =
2 \1/2 (AI/2) 1"b
VtlJ-l/ *• /
a(l-b)U
where
,\
(Zi+l)1-" - (2i-l)1-bJI <">
a, b, are empirically determined con-
stants used to specify dispersion; they
are functions of the atmospheric sta-
bility,
AL is the size (width) of the area
sources,
N is the number of upwind sources
i is a specific upwind source
QQ is the pollutant emissions for the
area in which the receptor site is
located,
Q. are the emissions for upwind areas
U is the average wind speed for the
averaging time of interest.
The model is applied to each subarea within the
metropolitan area. The application is made for
the wind direction, wind speed and stability
class for each meteorological situation under
consideration. All sources upwind of the recep-
tor area are included in determining the pollutant
impact. This approach may be used to estimate
hourly average concentrations for all situations
of interest. Concentrations for other averaging
times can be obtained by estimating concentrations
for each hour of the period and averaging the
hourly concentrations.
In those cases where:
Source strengths Q. do not differ signi-
ficantly from source strength Q
78
-------
The grid areas are relatively large
(county size) ,
it has been shown that the Hanna-Gif ford equation
for the change in concentration simplifies to:
AX = C (23)
where U is annual average wind speed and AQ is the
change in the average emission density (g/sec-m2)
for each area. Values for the constant C, which is
dependent on the pollutant, may be determined em-
pirically from observed data.
*****
Any one of the techniques summarized above would
be implemented in a similar manner. The model devel-
oped in the previous section may be used to estimate
changes in emission densities. For the rollback or
Appendix J methods, the change in the emission density
for the entire metropolitan area should be calculated.
For the Hanna-Gif ford method, the change in the emis-
sion density of subareas is required; the smallest
subarea for which building counts are readily avail-
able is ordinarily the county level.
An accurate estimation of 1, 3, 8 or 24 hour av-
erages for any pollutant requires more than annual
average emission rates. Hourly emission rates are
usually used, and added to form emission rates for
longer periods. If emission rates for the shorter
time periods are not available, the only alternative
is to allocate annual emissions to smaller time periods.,
thus assuming that hour-to-hour variations in emission
rates will not have a significant effect on estimated
pollutant concentrations.
The approach described above/ which involves allo-
cating annual fuel savings from solar systems uniformly
to smaller time periods, will not produce a true repre-
sentation of actual hourly or daily emission rates.
It is clear that residential and commercial space
conditioning fuel "use varies seasonally, diurnally, and
79
-------
is affected by unusual climatic conditions. The hot
water load in any building depends on the use patterns
of the occupants.
(2) Air Quality Impacts Due to Reduced Demand For
Electricity
Electricity provides a significant portion of the
residential and commercial space conditioning and hot
water load. Many domestic hot water heaters and most
residential air conditioning systems are electric. Be-
cause of natural gas curtailments, many new buildings
are equipped with electric space heat. Solar systems,
especially when installed in new buildings, will result
in savings of electricity.
The question of how solar-induced electricity sav-
ings will impact air quality in an urban area is a com-
plex one. A change in the emission levels due to power
generation will occur if solar systems reduce peak elec-
trical demand, or if widespread use of solar systems re-
duces the need for new generating capacity. These two
considerations are discussed in more detail below.
Whether solar systems will reduce peak demand de-
pends on the operating characteristics of the utility
and the patterns of solar energy utilization. The lat-
ter, as discussed previously, depends on climate (out-
door temperature, humidity and wind) and the duration
of periods of sunshine.
The following examples illustrate the potential
impacts which different applications of solar energy
can have on a utility load:
In some cold climates, winter peak demands
tend to occur during overcast periods, and,
as a consequence, the conventional heating/
cooling system, which is required as an aux-
iliary in almost all solar system applications,
would likely be required simultaneously with
the utility's peak load, thus aggrevating the
requirement for peaking capacity. Although
this situation could conceivably be avoided
by installation of a large storage system
which was maintained at an elevated tempera-
ture, even during overcast periods, by use of
the auxiliary system at off-peak hour's, the
80
-------
potential requirement for peaking capacity
would remain unless the utility were able to
control the auxiliary system directly.
In a warm climate the utility will likely
have a summer peak. Peak cooling loads might
tend to be significantly reduced by applica-
tion of solar energy in areas where the hottest
days, as well as the hottest periods of the
day, correspond closely to the times when the
sun shines brightest.
Hot water energy requirements are usually
less than 10 percent of the total residential
and commercial energy demand. While hot
water requirements alone will probably not
be large enough to affect peak electrical
demand significantly, they may have a con-
tributory effect. Peak domestic hot water
loads usually occur in the mornings and even-
ings, while commercial hot water loads peak
at different times depending on the type of
establishment.
Whether solar systems reduce peak demand will de-
pend, therefore, on characteristics unique to each
urban area. Typical monthly load duration profiles
characterizing utility operations are shown in Fig-
ure 8. Three hypothetical cases involving solar sys-
tems applications are shown in the figure. In the
first case, solar energy reduces peak demand. In the
second case, the base load is affected, and in the
third, both the peak and base load are reduced.
A change in peak electrical demand has a direct
air quality impact. Peaking units are brought on line
to supplement base generating capacity at times of peak
demand. In many cases peaking units are the oldest and
least efficient units in the system, or are gas turbines
fired with distillate oil. In many cities the older
generating stations are located in the urban area rather
than in surrounding rural areas. Thus reducing peak
demand will often result in a decrease in power plant
emissions in the downtown area, the most critical area
from an air quality standpoint. This will be true even
if the reduction in peak demand is occasional and not
long term.
A change in base electrical load will not have as
direct an impact on air quality. First of all, the base
81
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FIGURE 8
Possible Impact of Solar
Energy Utilization on
Load Duration Profiles
LOAD
MW
PEAK
INTERMEDIATE LOACf
BASE LOAD
.HOURS OF MONTH*-
NORMALDEMAND
NORMAL DEMAND REDUCED
BY SOLAR SYSTEMS
REDUCED PEAK LOAD
LOAD
MW
INTERMEDIATE LOAD
REDUCED BASE LOAD
•HOURS OF MONTH*
LOAD
MW
REDUCED PEAK, INTER-
MEDIATE AND BASE LOAD
-HOURS OF MONTH *-
*The number of hours in a month for which the load was greater than or equal to the
ordinate value.
82
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load reduction must be substantial in order to reduce
the amount of spinning capacity on line. The reduction
must also be long term and not an irregular occurrence,
such as a daily or seasonal fluctuation in electrical
demand. A long term, substantial change in base load
would most likely impact the construction of new gen-
erating units. This is because any change in base load
would occur gradually, over a long period of time. If
the new generating capacity in question were fossil-
fueled, there would be a resulting air quality impact.
If the new capacity were nuclear, however, other en-
vironmental considerations, including risk of radio-
active material release and disposal of radioactive
wastes, would be involved.
One critical aspect concerning a potential reduc-
tion in base load capacity, as mentioned above, is that,
in general terms, the system demand must be decreased
by an amount equal to the full capacity of a specified
generating unit before that unit can be taken off line.
It is possible that solar energy systems alone may not
cause this much of a reduction. Energy conservation
strategies, such as improved insulation and adoption
of lower illumination levels, and computerized temper-
ature controls, can also contribute to reducing base
load. It is important when electrical base and peak
loads are analyzed, that the combined effect of all
supply and demand strategies be included in the analy-
sis, even though individually the strategies may not
have significant impact.
In the event that solar energy utilization does
contribute to a reduction in the rate of electricity
generation, particulates, sulfur oxides and nitrogen
oxides are the criteria pollutants for which emission
levels would be most significantly affected. Table 20
shows nationwide 1972 emission levels for the criteria
pollutants. Referring to the table, generation of elec-
tricity for residential and commercial use produced a
substantial portion of TSP (9.4 percent), SO (29 per-
cent), and NOX (13.1 percent) emissions on a nationwide
basis.
In many metropolitan areas, the major sources of
TSP and SO emissions are stationary fuel combustion
and industrial process facilities. Urban areas which
contain several electricity generation stations, and
comparatively little heavy industry, would be the areas
for which reduced electricity demand resulting from
83
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Table 20
Nationwide Emission Levels (1972)
Emission Sources
TSP
Emissions (1,000 Tons Per Year)
SO,
NO,,
HC
CO
Electricity Generation
Residential use only
Commercial use only
Total (all users)
1,083
779
3.385
5,564
4,000
17,388
1,882
1,353
5.881
23
17
72
75
54
235
Mobile Sources
774
625
8,721 16,279 77,418
Grand Total
All Point Sources
All Area Sources
19,790
15,018
4,772
33,208
28,902
4,306
24,642
14,091
10,551
27,791
6,969
20,822
107,303
19,037
88,266
Sources: Emission data: EPA, 1972 National Emissions Report (June 1974).
Distribution of electricity generation emissions: "Twenty-sixth Annual
Electrical Industry Forecast," Electrical World, September 15, 1975
(contains electrical usage for 1972: residential [32%] commercial [23%]
of total). Emissions from electricity generation were allocated to resi-
dential and commercial applications by assuming that emissions for all
pollutants are proportional to electricity usage.
solar energy utilization would have the greatest po-
tential impact on TSP and SOx (including fine particu-
lates and sulfates) concentrations.
As indicated in Table 20, almost half of the
NO emissions nationwide were caused by mobile sources,
primarily automobiles. In most urban areas, therefore/
where automobile use is heaviest, solar energy utiliza-
tion would probably not affect NO^ concentrations to a
significant extent.
84
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Standard procedures for estimating the changes in
pollutant concentrations due to changes in point source
emission rates require definition of the following:
Meteorological data (wind speed and direction,
atmospheric stability and mixing height)
Location of the plant
Stack parameters (height, diameter, exit
temperature and exit velocity)
Hourly emission rates.
The last two parameters above depend on which generat-
ing unit or units at the plant are affected and the
fuels burned by those units. Most point source dis-
persion models use the standard Gaussian diffusion
equation to predict long-term pollutant concentrations
from the above data.
A generalized assessment of the air pollution im-
pact of solar systems may be made without detailed
point source dispersion modeling. This approach in-
volves estimating only the areawide power plant emis-
sion reduction (in tons per year) which corresponds to
expected electricity savings. The methodology pre-
sented in the previous section defined the areawide
fuel savings for electricity in year T* as UT£,(T )
(for the subscript k' corresponding to electricity.
The subscript k referred previously to the type of
end-use fuel consumption and is. omitted below since the
only end-use fuel savings considered is electricity.
The subscript k is used below for the type of fuel
burned at a power plant. Using the notation of the
preceding section, define FFC, (T ) as the fraction of
JC X
the total electricity savings corresponding to power
plant fuel k*. Also define CE, as the conversion ef-
ficiency for fuel k, defined as (kwh of delivered elec-
tricity) /(unit of fuel input"*") . The term CEk thus in-
cludes generation and transmission losses. If EF .
Thus Y* FFC (T ) =1.0
k k X
Such as tons of coal, gallons of oil, etc.
85
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are the emission factors (pounds of pollutant per unit
fuel k) , then the emission reduction for pollutant p
is given by:
AEp(Tx) = £ UT£, (Tx) x FFCk x EF/CE (24)
k
Note that UT (T ) above must be expressed in kWh/yr.
Emission factors for the most common power plant fuels,
are given in Table 21. Typical values for gen-
erating conversion efficiencies CEV are given in
Table 22. K .--•••
In summary, therefore/ the potential air quality
impacts due to reduced demand for electricity depend
on the manner in which patterns of solar energy utili-
zation affect daily and monthly load profiles of the
electric utility in the urban area. To define this
impact with any degree of accuracy, a careful analysis
of all pertinent factors which are unique to that
region must be performed, as they have been earlier in
this section, to determine source emission reductions
from buildings. Several of the factors that might be
considered in this analysis include the following:
The existing source of electrical power for
the region. Displacement of coal burning
plants offers a larger potential for reduced
emissions than do low-sulfur oil- or gas-fired
units.
The location of the existing generating ca-
pacity. The location being analyzed (e.g.,
a countywide region) may, in fact, have no
power plants within its borders. In this
case, any changes in the regional load pro-
file due to solar market penetration will
impact air quality most directly in the
region containing the power plant.
How anticipated acceptance of solar heating
and cooling systems will modify current load
profiles. As stressed earlier, the effect on
the peak, intermediate and base load profile
characteristics must be defined before ex-
plicit analyses of impacts can be carried out.
86
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Table 21
Emission Factors For Common Power Plant Fuels (EFe. )
pk'
Fuel (k)
Bituminous Coal
Residual Oil
Distillate Oil
Natural Gas
TSP
2. 2 A
8
8
15
SOX
38 S
159 S
144 S
0.6
Pollutant (p)
NOX HC
20 .3
105 2
105 2
600 1
CO
1
3
3
17
Units
Ib/ton
lb/103gal
lb/103gal
Ib/106ft3
Note: S is percent sulfur
A is percent ash
Source: EPA, Compilation of Air Pollutant Emission Factors (document AP-42), April 1973.
Table 22
Typical Conversion Efficiencies For Power Plants (CE, ) *
JC
Btu content CE.
Fuel(k) per unit fuel 1000 kWh/unit fuel Unit fuel
Bituminous Coal
Residual Oil
Distillate Oil
Natural Gas
26.2x106 2.3 ton
150x106 13.2 1000 gal
134x106 12.2 ttXWgal
U)9 87.9 106Cu. ft.
Note: Assumes 33% thermal efficiency and 8% transmission loss (11,373 Btu burned/kWh delivered).
"Includes generating and transmission losses.
87
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Once changes in load profiles are forecast, it can
be determined if the resulting reduced demand may be
satisfied by reducing the number of units already on
line (which will reduce emission density in the region)
or by lowering load growth projections and delaying
construction of new capacity.
3. SUMMARY OF THE METHODOLOGY
The methodology described in the previous two sections
for estimating the annual fuel savings due to solar heating
and cooling systems may be summarized as follows:
T is the year for which the methodology is used
X
to" calculate annual fuel savings
T is the base year to which areawide growth is
referenced
Subscripts;
j = building type
k = fuel
m = application (heating, cooling, hot
water)
Input data;
G(T ) is the growth index for the region
referenced to base year T
FFN., are the fuel use factors for new
buildings (percent of all new buildings
using fuel k for application m)
S(T) is the parameter defining the rate of
market penetration of solar systems (percent
of new buildings which are equipped with
solar systems in year T), assumed to be the
same for all building types j
N.(T ) is the building stock of type j in the
base year T .
88
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The key equations of the methodology are:
(1) Solar-related energy savings (Btu) per building
(equation 1) :
E . = B . x F .
Dm urn
Typical values for B. are given in Tables 12
and 13; typical values for F. are given in
Tables 14 and 15.
(2) Potential fuel savings per building (equation 3)
i _
U— X / TPTi'M -v T? /LIT \
• i ~~ ~~ f v r r IN >« Ji KJ , /ni^. i
DK c, / j ]Km jm Km
m
Typical values for HEkm are given in Table 16.
(3) Annual rate of construction of new buildings
(equation 10):
ln(G(T ))
c. = „ _T + 0.025
J x o
(4) Annual net rate of building stock change
(equation 11):
ln(G(T ))
P. = —_—_25—
(5) Average number of new buildings built in year T
(equation 13):
P.(T-T )
NS.. (T) - Cj x N. (TQ) e D ° (T s Tx)
89
-------
(6) Areawide residential fuel savings by year T
(equation 14):
x
url(T ) =
K x
all T < T
X
(NS.(T) xU.k
residential
(7) Areawide commercial fuel savings by year T
(equation 15): x
all TsT .
X
S(T) (NS.(T) x Ujk)
commercial
(8) Total areawide fuel savings (equation 16) :
= UT5(T
UTk(T:
(9) Change in annual areawide (area source) emissions
due to reduced on-site fuel combustion (equation 18) :
x
(onlv for on-site fuels k)
Typical values for EF^, and EP° are given in
Table 17. P
(10) Change in annual areawide emissions due to reduced
power plant fuel combustion (equation 24) :
x
FFC]C x
./CEx]
k
(only for electricity savings k')
Typical values for EFek are given in Table-21;
typical values for CEk are given in Table 22.
90
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4.
SAMPLE APPLICATION OF THE METHODOLOGY
This section illustrates how the methodology developed
in the preceding sections can be applied to forecast the
changes in emission and air quality levels in any urban area
due to utilization of solar technology for heating and cool-
ing residential and commercial buildings. For the purposes
of this example, several assumptions were made concerning
the input data required in order to expedite the analysis.
Therefore, the numerical results presented should not be
considered an accurate forecast of air quality impacts in
the metropolitan area studied.
The geographic region, type of housing, and timeframe
selected for this example were:
Geographic region; Baltimore, Maryland SMSA
Type of building; residential, single-family
(j=D
Projected timeframe; to the year 2000.
It should be emphasized that though only residential, single-
family homes are considered in this example, a complete anal-
ysis must include all building types existing in the geo-
graphic region under investigation.
The values for subscripts used in this example are
identified below:
Subscript
Identification
m
Building Type
1 - residential, single-family
Building Fuel
. 1 - distillate oil
2 - natural gas
3 - electricity
Application
1 - space heating
2 - space cooling
3 - water heating
91
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To determine the change in emissions in a particular
region, the following must be calculated:
The energy demand for single-family residences
in the region
Potential energy savings per building
Potential fuel savings per building
A forecast of the number of residences equipped
with solar systems
Areawide residential fuel savings
The expected change in emission density.
(1) Energy Demand for Single Family Residences in
the Region
Typical values for B. (expressed in Btu/year) are
given in Table 12 for space heating and cooling.
Values are giv<=n for cities in the different climatic
regions of the county. Table 13 contains typical
water heating loads. These values are summarized
below for single-family residential houses in the
Baltimore area:
Building Energy Demand,
Application B.-m (Btu/year)
Space Heating (BI;L) 112x10
Space Cooling (B12) 33x10
Water Heating (B13) 13.3x10
(2) Potential Energy Savings Per Building
Energy savings (Btu) per building are given by
equation (1):
Ejm (Btu) = Bjm X Fjm '
92
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where F. is that portion of the energy load that can
be satisfied by solar systems. Typical values for F.
are given for cities in the different climatic regions
of the country in Tables 14 and 15. The values for
Washington, D.C., in those tables were used in this
example:
F. : Portion of Energy
jm
Demand Satisfied By
Application Solar Systems (j=l)
Space Heating (F^) 0.46
Space Cooling (F12) 0.72
Water Heating (F13) 0.90
Applying these values in equation (1), the energy
demand satisfied by solar systems in single-family
houses is calculated to be:
m
= [(112)x(0.46) + (33)x(0.72) + (13.27)x(0.9)] 106
= 87.22xl06 Btu/yr
This is composed of:
E,, = 51.52x10 Btu/yr for space heating load
saved
E,, - 23.76x10 Btu/yr for space cooling load
saved
E13 = 11.94xl06 Btu/yr for water heating load
saved.
93
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(3) Potential Fuel Savings Per Building
The annual fuel savings possible in each type of
building is a function of the energy saved by using
solar systems (E. ), the percent of each type of fuel
used by these buildings to generate this energy level
(FFNjkm)/ and the efficiency expected from using these
different fuelstocks (HEkm). The relationship for per-
building fuel savings is given by equation (3):
m
where:
c
k = the energy per unit of fuel (e.g., Btu/
gallon of oil);
FFN-iv™ = Portion of buildings using each type of
I Jxill .ff. . ^ 1 •* ^
J fuel;
HEkm - the ratio of energy delivered or removed
to energy supplied for each type of fuel.
Typical values for HE. were given in Table 16.
Values for FFN..^ used in this example are shown in
Table 23. These values are for new residential
Table 23
Fuel Use Factors, FFN., *
jkm
Application
Fuel or
Energy Source
Heating Oil (k=1)
Natural Gas (k=2)
Electricity (k=3)
(m=1)
Space
Heating
0.60
0.00
0.40
(m=2)
Space
Cooling
0.00
0.00
1.00
(m=3)
Hot Water
Heating
0.00
0.00
1.00
* Source: EPA, Development of a Trial Air Quality Maintenance Plan
Using the Baltimore Air Quality Control Region,
September 1974.
94
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construction only. For this example it was assumed
that electricity will supply the space heating require-
ments for 40 percent of the new homes, as well as all
air conditioning and water heating energy requirements.
It is assumed that oil will satisfy the balance of the
residential heating load requirements with natural gas
(due to continued curtailment of this fuel) , coal and
other fuels (e.g., wood, propane, etc.) not used for
new homes. For this example, the value of U., are
given as follows using equation (3) : 3
= — (5 1. 5 2x10 6) Btu/yr
cl '
• U12 = 0 o^5 (51-
cTw) (23.76X106) (0)
U13 = c7 (lio) (51.52X106) (0.40)
+ (275-) (23. 76x10 / (l-OO)
I1-00)
= jp f50.01xl06J Btu/yr.
For heating oil, GI = 144,000 Btu/gal, and for
electricity, c3 = 3412 Btu/kWh; therefore, for
95
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residential, single-family homes in the Baltimore
SMSA, the potential per-building fuel savings are:
UI;L = 51.52xl06 Btu/yr = 358 gal of heating
oil/yr
. u12 = o
U13 = 50-°lxl°6 Btu/yr = 14.66x103 kWh/yr.
(4) Forecast of the Number of Residences Equipped
With Solar Systems
The number and types of buildings in a region is
an important statistic that is used as a base upon
which the per-building energy savings resulting from
solar system applications can be obtained. Inherent
in this analysis is the assumption that solar systems
will not be retrofitted in existing structures due to
high cost but will be applied exclusively in new con-
struction.
The following data were used in this example:
T = forecast target year = 2000
^t
TO = base year = 1975
N1(TQ) = 455,984 (the number of residential,
single family dwellings in the Baltimore
SMSA)*
G(Tx) = 1.184 (the areawide growth index for
the year 2000/ referenced to 1975).
Source: 1970 Census of
Excludes mobile homes and trailers.
Housing—Maryland.
Based on population growth projections for Baltimore SMSA.
Source: OBERS Projections, Population Series, U.S. Water Resources
Council, April 1974. For this example, the building growth rate
is assumed to be the same as the projected growth rate' for the
population in the region (a statistic easily obtainable). A more
thorough analysis, however, must either verify this relationship
or obtain a more accurate indication of G(T ).
96
-------
The annual rate of new construction for residential
buildings (j=l) is given by equation (10):
In G(T )
c, =
x + 0.025 = 0.0318.
'1 T -T
x o
The net rate of exchange in the building stock is given
by equation (11):
P = c, - 0.025 = 0.00676.
The average number of new houses built in year T is
qiven by equation (13):
P(T-T )
NS1(T) = c1 x N-^T^ e
In this example, the number of new houses (j=l only)
built at the midpoint of each five year period between
1975 and 2000 was calculated and used as an annual esti-
mate for each year in that period. The average number
of new single-family buildings built during each of the
years period between 1975 and 1980 is (from equation 13):
0.0318x(455,984) e(-00676)2.5 = 14/727 houses per year.
Since this number represents the average new construction
during the five year period, the total new construction
between 1975 and 1980 is:
14,727 buildings/yr x 5 yrs = 73,634 new buildings.
New construction for each of the other 5-year periods
is calculated in a similar manner and the results are
presented in Table 24.
(5) Areawide Residential Fuel Savings
The fuel savings during the year 2000 in a metro-
politan area for single-family residences is given by
equation (11) with j=l:
= ulk £ s(T) x
all T
S T
x
97
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Table 24
Projected Number of Single-Family Dwellings
to be Built to Year 2000 in Baltimore SMSA
Period
(Year)
1975-1980
1980-1985
1985-1990
1990-1995
1995-2000
Total
Average Annual
Construction (Bldgs/Yr)
14,727
15,233
15,757
16,298
16,859
New Construction (1975-2000)
Total New
Construction (Bldgs)
73,634
76,165
78,784
81,492
84,294
= 394,369
where T is the year 2000. The per-building fuel sav-
ings, uljc/ and the average number of new homes built in
each year T, NS^ (T), were calculated earlier in this
section.
The rate of market penetration of solar systems,
S(T), which was used for this example is shown in Fig-
ure 9. The rate of solar system acceptance is the
parametric input for the mathematical model devel-
oped previously in section 1. The values for S(T) in
Figure 9 reflect a maximum market capture of 70 per-
cent, and a capture rate which approximates the normal
(Gaussian) cumulative distribution function with
+3a at 1975 and 2000.
98
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1975
1980
1985
1990
1995
2000
Assumptions:
Market capture limit is 70%. Capture rate approximates the normal cumulative
distribution function with ±3a at 1975 and 2000.
FIGURE 9
Assumed Solar Market Capture (S(T))
The following data may be used to evaluate equa-
tion (11) :
Time Period (T)
1975-1980
1980-1985
1985-1990
1990-1995
1995-2000
S(T)
0.0056
0.0805
0.3500
0.6195
0.6993
Time Period S(T) NS(T) Z(S (T)xNS (T))
412
6,131
27,574
50,484
58,948
143,549 buildings
by 2000
1975-1980
1980-1985
1985-1990
1990-1995
1995-2000
0.0056
0.0805
0.3500
0.6195
0.6993
73,634
76,165
78,784
81,492
84,294
99
-------
The.per-building fuel savings, ulk were calculated pre-
viously as 358 gallons of oil and 14.66xl03 kWh per
year. Therefore, the residential fuel savings in the
year 2000 will be:
143,549 x 358 gal/yr = 51.4 million gallons
of heating oil
143,549 x 14.66 x 103 kWh/yr = 2.1 x 109 kWh
(6) The Change in Areawide Emissions
The change in area source emissions in the Baltimore
area is given by equation (18):
*EP(V -E
Since only single-family residences are considered in
this example, and since the previous analysis indicated
that the only area source fuel savings (UT£ or UTC) will
be distillate oil (fuel is subscript k), the above
equation simplifies to:
AEa(T ) = UTr(T ) x EFr
p x x x p
This expression is evaluated in Table 25 below:
Table 25
alculation of
UTrk(Tx>
51. 4 x 106 gal/yr
51.4 x 106 gal/yr
51. 4 x 106 gal/yr
51. 4 x 106 gal/yr
51. 4 x 106 gal/yr
Area Source
Pollutant p
TSP
SOX
NOX
HC
CO
Emission
EFr,» A
c pk
10
43.2
12
3
5
Reductions
Ep(Tx) tons/yr
257
1110
308
77.1
128.5
'Emission factors for distilled oil are from Table 17; units are lb/103 gal.
Emission factor for SOX is 144 S where S (percent sulfur) for Baltimore
is assumed to be 0.3.
100
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The change in areawide emission levels due to dis-
placement of power plant coal use by solar heating and
cooling systems is given by equation (24) :
x
when UTk(Tx) is 7.165 x 1012 Btu/yr. (this term must be
expressed in Btu and corresponds to an end-use elec-
tricity savings of 2.1 x 109 kWh/yr) . Since in this
example bituminous coal is the only power plant fuel
saved (FFC. = 1) , the above equation simplifies to:
AE®(Tx) = UT£(TX) x EFpk /CEk (k = coal only).
This expression is evaluated and the results pre-
sented in Table 26 below:
Table 26
Calculation of Power Plant Emission Reductions
UT1 (Tx)
2.1 x 104 kWh/yr
2.1 x 104 kWh/yr
2.1 x 104 kWh/yr
2.1 x 104 kWh/yr
2.1 x 104 kWh/yr
Pollutant p
TSP
S0x
NOX
HC
CO
EFpk* CEkt
22 2.3
38
20
0.3
1.0
A Ep(Tx), tons/yr
10,043
17,348
9,130
137
457
Emission factors are from Table 111-12; units are Ib/ton. Emission factor for TSP is 2.2 A where
A (percent ash) for Baltimore is assumed to be 10. E
(percent sulfur) for Baltimore is assumed to be 1.0.
A (percent ash) for Baltimore is assumed to be 10. Emission factor for SOX is 38 S where S
^Generating conversion efficiency is from Table 22, in 1000 kWh/ton of coal.
101
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The total estimated change in areawide emissions
is the sum of the area source emission savings AEa
(on-site fuel combustion) and power plant emission
savings AEe. In Figure 10, total areawide emission
savings are compared to 1972 areawide emission levels
for Baltimore. The estimates of emission savings are
based on several assumptions concerning market pene-
tration and fuel savings. These estimates illustrate
the order of magnitude of the potential air pollution
impact, using 1972 emission levels as the baseline for
the comparison.
5. PARAMETRIC ANALYSIS OF REGIONAL EMISSION SAVINGS
One key feature of the methodology for forecasting
changes in annual emissions described in this chapter is
that it can be used for parametric analyses. In this sec-
tion this feature of the methodology is demonstrated by:
Using the Baltimore data given in the previous
section to describe fuel use and emission charac-
teristics of a hypothetical city
Simplifying the equations to express emission
changes as a direct function of one parameter
(rate of market penetration)
Using the simplified equations to develop emission
forecasts which correspond to several assumed mar-
ket penetration rates.
Solar related energy savings per building are given by
equation (1) :
Ejm = Bjm X Fjm
Potential per-building fuel savings are given by equation (3):
If it is assumed that solar systems will be installed only
in new buildings, and that the only fuel savings will be coal
102
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FIGURE 10
Potential Emission Reductions
in Baltimore Associated with
the Use of Solar Heating/
Cooling Systems in Single-
Family Dwellings in the Year
2000, Compared to Total 1972
Emissions in Baltimore
TSP
SO
10,300(2.4%)
TRY
18,458 TRY (7.3%)
426,183 TRY
9,438 TRY
(5.5%)
253,517 TRY
(Assuming
1% sulfur
content)
214TPY
(0.12%)
CO
585 TRY
.08%)
Note:
1972 Areawide emissions, 1972*
TRY: tons per year
Potential emission reduction using
1972 areawide emissions as a
basis for comparison
"EPA, 1972 National Emissions Report (June 1974)
These potential emission reductions are based on a postulated rate of solar market penetration and
future areawide fuel distribution.
This comparison is made only to show the relationship between the magnitude of potential emission
reductions in the year 2000 and the magnitude of emission levels in 1972. It >snot meant to imply solar •
systems could reduce by 7% the total SOX emissions in the year 2000.
103
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used to generate electricity (subscript k above is constant)
then per building energy savings can be expressed as:
Bjm * Pjn,/HEm
since FFN. = 1.0 for all j and m. Evaluation of this ex-
3m
pression gives a constant value for each U.,, i.e., a matrix
of constants
The total areawide fuel savings by year TX (using equa-
tions 13 through 16) is:
t
UT£(T )
all T
^ I
S(T) Jj c. x u. x N.(T )
P,(T-T )
The annual rate of construction c . , and the annual net rate
of building stock change P . were calculated in the previous
section as 0.0318 and 0.00676 respectively (constant for all j) .
If it is assumed that the parametric input S(T) is constant
over time (the same rate of acceptance each year) , the above
equation may be written as:
parametric
input
constants
building
stack in
the base
year
The change in power plant emissions due to fuel savings
) is given by equation (24) :
If it is assumed that the only power plant fuel savings will
be coal (therefore subscript k above for power plant fuel will
be constant). then the change in power plant emissions is:
104
-------
EF/CE
= S(T) xl V e
parametric
input
constants
building stock
in the base year
Thus/ for the assumptions of this example, the entire
methodology for estimating emission changes has been reduced
to one equation involving:
The rate of acceptance of solar systems (the para-
metric input)
The building stock in the base year
Several numerical constants.
This equation has been evaluated for the year 2000 for
market acceptance rates of 10 percent, 20 percent, and 30
percent. (The percent of new buildings equipped with solar
systems.) The results are summarized in Table 27 and
Figures 11 and 12. The base year building count from
which these forecasts were made was calculated from the
nationwide building counts given in the GE Phase "O" report,
allocated to the hypothetical city using the ratio of Balti-
more's population to total U.S. population. For this reason
the energy savings forecast should be considered as a repre-
sentative estimate only. It can be seen from these data
that the building types for which the largest potential fuel
savings are projected due to solar heating and cooling sys-
tems use are (in descending order) heavy industrial, single-
family houses, light industrial, retail malls, and audito-
riums .
105
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ANNUAL
ELECTRICITY
SAVINGS BY
YEAR 2000,
(109 KWH/YR)
FIGURE 11
Potential Energy Savings in
Hypothetical City
(Displacement of Electricity
Only)
TOTAL SAVING:
18.4 X 109
KWH/YR
Notes:
I.
2
All solar-induced fuel saving is electricity
Nationwide building stock* allocated to hypothetical city using
Baltimore population
3. Constant rate of acceptance of solar systems: 30% of alt new buildings
4. Energy savings by building type taken from Table 27
*From GE Phase 0 Report
106
-------
en
II
CO UJ
(T
Ul UJ
_i a-
< w
II
<
500-
400-
300-
200-
100-
1972 TSP EMISSIONS
426
.10% ) REDUCTION IN TSP EMISSIONS IN
,20% ? YEAR 2000 FOR VARIOUS LEVELS
•30% I OF MARKET ACCEPTANCE
253
' 1972 SOX EMISSIONS
.10%
,20%
,30%
REDUCTION IN SOX EMISSIONS IN
YEAR 2000 FOR VARIOUS LEVELS
OF MARKET ACCEPTANCE
TSP
SO.
Notes:
1. 1972 emission levels: Baltimore SMSA areawide emissions, (EPA 1972 National
Emissions Report)
2. All solar-induced savings will be electricity from coal
3. Coal sulfur content: 1%
4. Market acceptance is percent of new buildings equipped with solar heating/cooling
systems
5. Areawide 25-year growth index: 1.2.
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-------
Table 27
Estimated Electricity Savings For
Building
Type (j)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Per-Building
Energy Savings,
103 kWh/yr (Uj)
34.6
1,007
1,382
3,592
892
684
397
1,191
2,952
6,500
1,218
1,083
695
206
810
27,087
198
Base Year
Building Stock
(Nj (To))
455,984
35
1,565
15
491
68
5,368
2,888
4,183
3,040
1,453
203
5,046
104
276
248
10,227
Hypothetical City
Energy Savings (Year 2000),
106 kWh/yr, (10% Market
Penetration)*
1,366
3
187
5
38
4
184
298
1,069
1,711
153
19
304
2
19
582
175
6,121 x 106kWh/yr
*Note:
• 10% market penetration: 6,121 million kWh/yr
• 20% market penetration: 12,242 million kWh/yr
• 30% market penetration: 18,363 million kWh/yr
108
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The energy savings and air quality improvement in an
urban area due to the use of solar heating and cooling sys-
tems will depend on several factors, especially the rate at
which solar systems are utilized/ the specific fuels which
are displaced, and patterns of energy demand and supply for
the area. The methodology described in this chapter is a
mathematical model for estimating this improvement in air
quality for any urban area. The model defines the relation-
ships between potential fuel savings (U) and associated reduc-
tion in air pollution emissions (E):
E = f-^N, G, S, F)
U = f2(E)
based on:
The current building stock in the area(N)
The expected areawide growth index (G)
Any postulated rate of solar system utilization (S)
Estimates of the fuels which will be displaced by
solar systems (F)
The sample application of the methodology indicates that
under certain circumstances the use of solar systems will re-
sult in significant emission reductions for some urban areas.
Since the majority of solar systems will be installed in new
rather than existing buildings, and because electricity is
used most often for space conditioning of new buildings, it
is likely that the use of solar energy will displace coal
and oil used to generate electricity. In this case, the air
pollutants for which potential reductions would be most sig-
nificant would be suspended particulates and sulfur oxides.
Using actual building stock data for Baltimore, and a 25
year areawide growth index of 1.2, emission reductions of
up to 2.4 percent for TSP and 7.3 percent for SOX were
estimated, assuming all fuel savings would be coal burned
to produce electricity.
A key feature of the methodology is that it can be used
for parametric analyses. This feature makes the methodology
well suited to the evaluation of solar heating and cooling
as a technological option for controlling air pollution.
It is recommended that the model be included in air
quality forecasts for an AQMA where large scale use of
solar heating and cooling systems are expected in order to
assess in more detail the long range impacts on air quality.
109
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GLOSSARY OF SYMBOLS
-------
GLOSSARY OF SYMBOLS
Term Definition
Subscripts:
j - Building type
k - Fuel type
m - Application (heating, cooling, hot water)
p - Pollutant
A Area
B. Energy demand in the region
BTU. Btu per building type in a region
c. Rate of construction of new buildings of type j
Ck Btu content per unit of fuel k
CE. Generating conversion efficiency
d. Demolition rate for buildings of type j
AE Change in emissions from area sources
6
AE Change in emissions from power plants
tr
AQ Change in emission density
Eim Potential energy savings per building type per
application
C
EF . Emission factor (commercial end-use consumption)
Q
EF . Emission factor (power plants)
EF . Emission factor (residential end-use consumption)
F^m Fraction of energy load that can be supplied by
solar systems
110
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Term Definition
FFC, Fuel use factor (power plants)
FFN., Fuel use factor (end-use consumption)
jkm
G(T ) Growth index for a region for year TX referenced
x to base year TQ
HEkm Heating/cooling equipment efficiency
N. Total number of buildings of type j
NET. Number of solar retrofits in buildings of type j
NST. Number of new solar-equipped buildings of type j
S.(T) Percent of new buildings equipped with solar sys-
3 terns in year T
t Time
T Base year to which areawide growth is referenced
T Year for which fuel savings are forecast
U.. Fuel savings
Areawide fuel savings (commercial buildings)
Areawide fuel savings (residential buildings)
Areawide fuel savings (total)
111
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TECHNICAL REPORT DATA
(Please read. iHOrurtiuits un the rcivrsu lit litre romp/cling)
REPORT NO.
3. RECIPIENT'S ACCESSION-NO.
J. TITLE AND SUBTITLE
POTENTIAL ENVIRONMENTAL IMPACTS OF SOLAR
HEATING AND COOLING SYSTEMS
S.-REPOHT. DATE
May 1976
6. PERFORMING ORGANIZATION CODE
. AUTHORIS)
T.J. Consroe, F.M. Glaser, R.W. Shaw, Jr.
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Booz, Allen & Hamilton
Applied Research Division
4733 Bethesda Ave.
Bethesda, Maryland 20014
1O. PROGRAM ELEMENT NO.
EHA-535
11. CONTRACT/GRANT NO.
68-01-2942
12, SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF RF.PORT AND PERIOD COVERED
Office of Energy, Minerals and Industry
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
Pprv
3RIN
14, SPONSORING AGENCY CODE
._EPA-QRD.
1&. SUPPLEMENTARY NOTES
16. ABSTRACT
The subject of this report is the potential environmental conse-
quences of solar energy utilization for heating and cooling buildings.
The report contains three chapters. The first chapter identifies the
areas in which both positive and negative impacts are possible. The
second chapter summarizes the national research and development program
directed toward solar heating and cooling technology and describes how
these programs address environmental considerations within the context
of Federal agency responsibilities. The third chapter contains a gen-
eral methodology for estimating the impact on air pollution of solar
energy utilization in urban areas, and also contains an example appli-
cation of the methodolo'gy.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
It). IDENTIFIERS/OPEN ENDED TERMS
c. COS AT I l;il!lll/Group
Environment
Energy Conversion
Solar-Utilization
Energy Cycle
Ecological Effects
Advanced Systems
10B
04
18, DISTHIHUTION STATEMENT
Release Unlimited
ID. SECURITY CLASS (This He/Kirl)
_ _LL C_ .
2O. SECURITY CLASS (Tliis pjgcj
U.C.
2t. NO. Of PAGES
22. PR ICG
EPA Form 2220 1 (S-731
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