Comments Received by the U.S. Environmental Protection
Agency During the Public Review Period
(February 27, 2007 - March 29, 2007)
of the Draft Inventory of U.S. Greenhouse Gas Emissions and
Sinks: 1990-2005
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Comment 1
Lisa McFadden—National Lime Association
February 22, 2007
Re: Request for public comment on draft of "EPA's Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-2005."
Dear Mr. Hockstad & Ms. Hanle:
Thank you for the opportunity to comment on the draft of "EPA's Inventory of U.S. Greenhouse
Gas Emissions and Sinks: 1990-2005." Like past reports, the Industrial Processes chapter of the
report updates estimated greenhouse gas releases from lime manufacturing (section 4.4, Lime
Manufacture (IPCC Source Category 2A2).
We have one editorial comment concerning that section. On page 4-15, the first paragraph
currently states the following:
2 Production was adjusted to remove the mass of chemically combined water found in hydrated lime, using the
3 midpoint of default ranges provided by the IPCC Good Practice Guidance (IPCC 2000). These factors set the
4 chemically combined water content to 24.3 percent for high-calcium hydrated lime, and 27.3 percent for dolomitic
5 hydrated lime, (emphasis added)
We believe the reference to "using the midpoint of default ranges provided by the IPCC Good
Practice Guidance (IPCC 2000)," as highlighted above is incorrect because the basis for the
factors was not found in the IPCC 2000 guidance. Rather the factors were based upon the
molecular weights of H20 (18), Ca(OH)2 (74), and Ca(OH)2 Mg(OH)2 (132) for conversion of
dolomotic lime at 27% (18/74) and high calcium lime at 24.3% (18x2/132). Please see attached
the comments of Dec. 14, 2006 regarding this matter.
Please don't hesitate to contact me at 703.243.5463 if you have any questions concerning these
comments or if I can provide further information.
Sincerely,
Lisa McFadden
Director, Information Systems
Attachment:
December 14, 2006
Ms. Andrea Denny
U.S. Environmental Protection Agency
State and Local Climate Change Program
1200 Pennsylvania Ave., NW
Washington, DC 20460
SENT VIA E-MAIL
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 2
Sinks: 1990-2005
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Dear Ms. Denny:
Thank you for the opportunity to comment on the draft of EPA's Methods for Estimating Non-
Energy Greenhouse Gas Emissions from Industrial Processes, Volume 8, Chapter 6 (August
2004). As we discussed in our phone call today, we have two comments on the Section 4.2,
Carbon Dioxide from Lime Manufacture, Step (2) Correct for Moisture in Hydrated Lime:
1. On page 6.4-6, the percentages appear to be switched in the last line of the first paragraph:
"Using the midpoints as default values, the water content may be assumed to be 27
percent for high calcium lime and 24 percent for dolomitic lime."
Based upon the molecular weights of H20 (18), Ca(OH)2 (74), and Ca(OH)2 Mg(OH)2 (132), the
conversion factors for dolomitic lime would be expected to be 27 % (18/74) and high calcium
lime would be 24.3% (18x2/132). So the line should be corrected to:
"Using the midpoints as default values, the water content may be assumed to be 24
percent for high calcium lime and 27 percent for dolomitic lime."
This also appears to be a mistake in the EPA's Inventory of U.S. Greenhouse Gas Emissions and
Sinks, April 2005 (Section 4.4, page 4-15).
2. To be more precise, you may want to change the words "moisture" and "water" to "chemically
combined water." Note that this terminology is consistent with the EPA Inventory of U.S.
Greenhouse Gas Emissions and Sinks, April 2005 (Section 4.4).
If you or your contractor have any questions, I can be reached at ecovner@lime.org or 703-908-
0772.
Sincerely,
Emily Coyner
Director of Regulatory Issues
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 3
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Comment 2
Robert H. McFadden—GHG Associates
March 8, 2007
RE: Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks (1990-2005)
Comment on the Executive Summary : Table ES-9 Recent Trends in Various U.S. Data
and Global Atmospheric C02 Concentration; and Table 2.2 of Chapter 2.
This table raises a number of questions, including the meaning and purpose of including data on
global atmospheric C02 concentrations. It appears to imply a connection between various data
of one nation (the U.S.) with global atmospheric C02 concentrations. On its face, the table
appears to claim that the growth rates of U.S. greenhouse gas emissions, U.S. energy
consumption, U.S. fossil fuel consumption, U.S. GDP, and U.S. population are all somehow in
lock-step with the growth rate of the global atmosphere C02 concentration. It further appears
to suggest that the growth rates of six U.S. factors by themselves account for the global C02
concentration growth rate. In addition :
1. The table suggests a comparison of U.S. emissions of six gases with a global single
gas (C02) concentration . To be balanced, the growth rate trends of other
concentrations, such as methane and nitrous oxide, need to be shown. In fact, the growth
rate of atmospheric methane has declined since 1990.
2. The table appears to compare emissions with concentrations . as if on a one-to-one basis,
although the IPCC notes that in the case of C02 emissions only about 50% reach the
atmosphere. Thus, the growth rate of C02 emissions is not the same as the growth rate
of C02 entering the atmosphere
3. Moreover, since data on GHG emissions, energy consumption and GDP are shown, one
would expect to see data on energy and GHG intensity rates.
The simplest, cleanest solution would be to delete the atmospheric C02 concentration data. The
mandate of this report is emissions, not concentrations. The fact that this table has appeared in
earlier inventories is not a rational argument for it's validity or retention.
Robert H. McFadden
GHG Associates
5902 Mount Eagle Drive
Suite 1415
Alexandria, Virginia 22303
Phone: (703-329-0780)
Fax: (703-329-9630)
Internet: www.climateclearinghouse.com
Email: mcfadden-ghg@worldnet.att.net
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 4
Sinks: 1990-2005
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Comment 3
Michael R. Benoit
March 16, 2007
Comments on "Inventory of U.S. Greehouse Gas Emissions and Sinks: 1990-2005" -
Federal Register Feb. 27, 2007
These comments are being provided in response to USEPA's solicitation for comment in the
notice [FRL-8281-2] that appeared in Federal Register Volume 72, Number 38 on February 27,
2007.
Aside from a brief casual mention that water vapor is a "naturally occurring greenhouse gas," the
Agency's inventory never begins to acknowledge that water vapor is the single most abundant
greenhouse gas in the atmosphere which exerts a greenhouse effect that dwarfs the combined
effect of the other gases. Water vapor comprises 95% of greenhouse gas, compared to about
3.5% for carbon dioxide. EPA's inventory of greenhouse gas "emissions" also fails to include
non-anthropogenic sources of carbon dioxide, which account for over 97% of the total C02 in
the atmosphere. (Sources:
http://lwf.ncdc.noaa.gOv/oa/climate/gases.html#wv and
http://www.geocraft.com/WVFossils/greenhouse data.html)
It appears USEPA is deliberately playing into the hands of global warming activists and
alarmists by focusing its "inventory" solely on anthropogenic sources of greenhouse gases while
ignoring completely the fact that water vapor, which is almost 100% from natural sources
(mainly oceanic evaporation), overwhelms the contribution from all other sources, both natural
and man-made. No responsible inventory of greenhouse gases should ignore the dominant effect
of water vapor simply because it is not an "emission" in the usual sense of the term. Failing to
properly and prominently describe the well-understood role of water vapor puts the Agency in
the position of advocating a political perspective instead of reporting critical facts.
I urge EPA to add language to its greenhouse gas inventory making clear that it is accounting for
only about 5% of the greenhouse gases known to exist in the earth's atmosphere and that its
focus on anthropogenic sources of carbon dioxide relate to only 3% of total carbon dioxide
emissions because 97% of those emissions are from natural sources.
Absent those clarifications, EPA's greenhouse gas inventory provides a grossly inaccurate and
incomplete analysis that fosters continued public ignorance of the pivotal role played by water
vapor in the natural cycles responsible for changes in the earth's climate. Refusal to make such
changes in the face of abundant supporting data would amount to deliberate obfuscation and
would be an abdication of the Agency's responsibility.
Michel R. Benoit
PO Box 92
Madison, NH 03849
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 5
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Comment 4
Christopher Woodall—U.S. Forest Service
March 26, 2007
Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
Overall Comments: Given my national inventory responsibilities, I focused my review on the
forest sections, in particular dead wood. I found nothing egregiously wrong or incorrect. I see
many challenges with moving estimation of forest land C components, such as dead wood, from
model-based to sampling design-based. I have provided some "heads up" comments so that you
may be better prepared for changes to the national forest inventory in the years ahead.
Specific Comments:
1) Page 7-4, Line 15.1 don't know if this statement is true... are you talking about the proportion
of carbon per unit volume of trees.. .if so this statement is true. If you are talking about total tree
C content, then healthy growing large trees might always sequester more C than smaller trees.
2) Page 7-5, Line 1. Doesn't Alaska cause heartburn? I am interested to see how you will
reconcile 1990 estimates when the AK inventory comes online. As a head's up, west Texas was
never really inventoried. RPA estimates pegged the forest land at 10 million acres. The FIA
program manager for the Southern Research Station said that there are about ready to release
actual inventory estimates for west Texas.. .might end up being 50 million acres in reality.
Could cause problems in the years ahead with reconciliation?
3) Page 7-8, Line 30. "Snapshot" files will no longer be maintained in the future as we are
moving towards a more dynamic data management system. Linda Heath has been informed a
few weeks ago. This transition from older data management systems will be painful for static
estimation engines and applications; however, we will try to help these national estimation
efforts out. So in other words, forest carbon stocks and fluxes will be estimated using a different
database in the future.
4) Page 7-9, Line 27. Does the IPCC dictate that fine woody debris is included in the litter C
pool? They are inventoried in fundamentally different ways by FIA. Right now estimates are
based on Heath's FORCARB model, but we would expect in the future that these estimates will
be based on an actual inventory. Currently, the FIA soil indicator measures small fine wood
debris C (< 0.25 inches), while the down woody materials indicator estimates FWD C greater
than 0.25 inches. Not a problem for this manuscript.. .but just another head's up for the future.
Christopher Woodall, Ph.D. 1992 Folwell Ave, St. Paul MN, 55108
Forest Inventory and Analysis Ph: 651-649-5141 Fax:651-649-5140
U.S. Forest Service Web: www.nrs.fs.fed.us/peopleAVoodall
Northern Research Station Email: cwoodall@fs.fed.us
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 6
Sinks: 1990-2005
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Comment 5
William C. Herz—The Fertilizer Institute
March 27, 2007
The Fertilizer Institute Comments on the Draft Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990 - 2005
Dear Mr. Hockstad:
The Fertilizer Institute (TFI), on behalf of its member companies, submits comments in response
to the U.S. Environmental Protection Agency's ("EPA's") Notice of Document Availability and
Request for Comments, published in the Federal Register on February 27, 2007, and appearing
at 72 Fed. Reg. 8731. This Notice announces the availability of the "Draft Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990 - 2005" for public review and comment (hereinafter
referred to as "Draft Inventory").
Statement of Interest
TFI represents the nation's fertilizer industry including producers, importers, retailers,
wholesalers and companies that provide services to the fertilizer industry. Its membership is
served by a full-time Washington, DC, staff in various legislative, educational and technical
areas as well as with information and public relations programs. TFI's members produce
ammonia, urea, nitric acid, and phosphoric acid, manufacturing processes identified by EPA in
the Draft Inventory as causing or contributing to greenhouse gas emissions. As such, TFI and its
members have an interest in EPA's activities relating to the Draft Inventory.
TFI Comments
TFI offers the following comments on the Draft Inventory.
1. The Draft Inventory Does Not Recognize Benefits of Best Management Practice
Utilization in the Agricultural Land Management Category
Adoption of best management practices ("BMPs") that may eliminate or minimize greenhouse
gas emissions is critically important for agricultural producers and a priority for those who serve
them. The best ways to prevent urea volatilization are to apply it during cool periods, or to
incorporate the fertilizer as soon as possible after application preferably with tillage and
subsequent irrigation or rain. TFI and the International Plant Nutrition Institute ("IPNI")
maintain a joint Nutrient Use task force that seeks to encourage the adoption and utilization of
BMPs through a paradigm focused on the right product, applied at the right rate, time and place.
In addition, attention must be paid to balanced nutrition as the uptake of nutrients is dependent,
in part, on the availability of other essential nutrients. In fact, a recent study by Montana State
University confirms that urea fertilizer emissions can be greatly reduced by appropriate BMP
utilization, paying attention to environmental conditions at the time and shortly after
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 7
Sinks: 1990-2005
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application.1 Temperature and moisture can both affect urea hydrolysis rates and ammonia loss
from surface applied urea fertilizers. Although there is always a risk of losing nitrogen to the
atmosphere, well thought out planning can greatly minimize the potential for nitrogen loss.
In addition, fertilizer emissions can be reduced by the use of various enhanced efficiency
products, that may contain urease inhibitors or other means to more closely match the release of
nutrients to the crops' growth curve. The fertilizer industry is committed to the environmentally
sound and efficient use of its products. Modern farming practices use fertilizer nutrients to build
high yielding, nutritious crops, and also make it possible for people to continue to enjoy large
areas of land for forests, parks and wildlife areas.
The development of enhanced efficiency fertilizers, crop-specific BMPs, and precision
agriculture tools are central to our industry's environmental stewardship program. With the use
of these crop nutrients, farmers can improve efficiencies, by reducing losses to the environment.
As these tools are utilized by an increasing number of US farmers, we formally request that EPA
revise the estimates for this category to reflect their adoption and utilization within American
agricultural systems and reduce the greenhouse gas emissions by a corresponding amount.
2. The Draft Inventory Does Not Cite the Latest Urea and Ammonia Production
Given that the Draft Inventory covers the period of 2002 - 2005 we request that the figures given
for ammonia production, urea production, and urea net imports be updated to reflect 2005 data.
Domestic ammonia production declined by greater than 8% from 2004 to 2005 (10,939 M metric
tons in 2004 v. 10,143 M metric tons in 2005) and urea production by a similar 8.5% (5,755 M
metric tons in 2004 v. 5,267 M metric tons in 2005). This corresponds to a concomitant increase
in urea net imports of greater than 17% (4,231 M metric tons in 2004 v. 5,138 M metric tons in
2005).
TFI formally requests that greenhouse gas emissions for the Ammonia category be further
reduced by 8.5% to reflect 2005 production numbers.
3. The Draft Inventory Does Not Account for Increases in Ammonia Production Efficiency
In addition, our members are producing anhydrous ammonia with greater efficiency than ever
before. In reviewing the Draft Inventory, it appears that EPA has not accounted for
improvements in manufacturing process efficiency achieved since 1990 (please see attached
figure). For example, in 1990 it took greater than 34.5 million BTU to produce a ton of
anhydrous ammonia. In 2005, that same ton of anhydrous ammonia was produced using less
than 33 million BTU - an increase in production efficiency of 5.6%. TFI requests that emission
totals be decreased by 5.6% to reflect these gains.
4. Domestic Sources Have Emissions Attributed from Urea Imports
The methodology in the Draft Inventory also makes another unfair assumption regarding the
domestic nitrogen industry - the CO2 emissions from imported urea are attributed to the
domestic nitrogen industry. As stated on p. 4-11:
1 http://landresources.montana.edu/SoilFertilitv/ammonvolat.html
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 8
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The calculation of the total non-combustion CO2 emissions from nitrogenous fertilizers
accounts for C02 emissions from the application of imported and domestically produced
urea. For each ton of imported urea applied, 0.73 tons of CO2 are emitted to the
atmosphere. The amount of imported urea applied is calculated based on the net of urea
imports and exports.
The problem with this is that domestic manufacturers have these emissions rolled up into this
one category, when, in many cases, these are unique entities importing urea into the U.S. without
a corresponding domestic manufacturing concern. In addition, if this urea is produced in a
country also producing a greenhouse gas inventory document; then these urea emissions from
the field would be double counted using current IPCC methodology. This also assumes that all
imported urea is being applied to fields; which is not accurate. Some of this imported urea is
used as a product in chemical and manufacturing sectors; and the associated CO2 may not be
released or may be captured for reuse.
Finally, as stated in Section F of these comments, Canada has proposed that C02 emissions from
the use of urea will not be covered under their regulatory schemata and thus will not be
attributed to nitrogen fertilizer manufacturers.
5. The Draft Inventory Does Not Recognize "Off-Sets" for Using "Waste" Heat
TFI believes that the Draft Inventory should recognize for both the phosphate fertilizer and nitric
acid categories efforts by manufacturers to utilize "waste" heat that would otherwise be vented to
the atmosphere and reduce reported greenhouse gas emissions accordingly. This applies both to
the production of phosphate fertilizer and nitric acid. For phosphate production, the waste heat
from sulfuric acid production is recaptured and utilized to generate electricity and as a direct off-
set to use of other energy sources. This beneficial reuse scenario truly represents green energy
and should be recognized and encouraged by EPA and, as such, addressed in the Draft Inventory.
If necessary, TFI is willing to solicit this information from its members and report it to EPA. TFI
estimates that members' phosphate facilities, alone, off-set at minimum 6.8 to 10 million metric
tons of greenhouse gases by capturing waste heat in sulfuric acid production and making
electricity. This electricity is then sold back into the grid of the applicable power company.
TFI believes that the capture and use of this green energy should more than off-set all the CO2 or
equivalent that phosphate companies produce; and a partial off-set should be applied to nitric
acid production.
6. The Draft Inventory Inappropriately Attributes CO2 Emissions Associated with the
Application of Urea Fertilizer to Urea Manufacturers
In Section 4.0 of thq Draft Inventory, EPA discusses "Ammonia Production and Urea
Application" in a single subsection. See Draft Inventory, Section 4.3. In this subsection, EPA
discusses ammonia manufacture, with the co-production of CO2, and recognizes that many
ammonia manufactures capture the CO2 generated during ammonia production and use it in the
production of urea. See Draft Inventory, pg. 4-10 - 4-11. Despite this recognition, EPA
nonetheless attributes any CO2 released by farmers and others land applying urea fertilizer to the
ammonia and urea manufacturers. Id. at 4-11 ("Total CO2 emissions resulting from nitrogenous
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 9
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fertilizer production do not change as a result of this calculation, but some of the CO2 emissions
are attributed to ammonia production and some of the C02 emissions are attributed to urea
application").
Based on a review of the Draft Inventory, the ammonia/urea production category is the only
category where C02 emissions resulting from subsequent use of a material are attributed back to
the manufacturing industry. For example, in the "Petrochemical Production" subsection, EPA
describes the production of petrochemicals resulting in "small amounts of CH4 and C02
emissions." See Draft Inventory, pg. 4-36. There is no attribution of CH4, C02, and N2O
emissions from sources/processes using petrochemicals to the Petrochemical Production sector.
Rather, the sources that use petrochemicals are identified as the producers of the CH4, CO2, and
N20 associated with petrochemical combustion and noncombustion activities. See, e.g., Draft
Inventory, Section 3.4 ("Mobile Combustion"). Similarly, there is no attribution of greenhouse
gases associated with coal usage to coal manufacturers. See Draft Inventory, Section 3.5 ("Coal
Mining"). Rather, the sources that use coal are identified as the producers of greenhouse gases
associated with those uses. See, e.g., Draft Inventory, Section 3.2 ("Carbon Emitted from Non-
Energy Uses of Fossil Fuels"), Section 3.3 ("Stationary Combustion (Excluding CO2)").
Attributing CO2 emissions associated with urea application to ammonia/urea manufacturers is
significant. According to the Draft Inventory, in 2004 approximately 43 percent of the CO2
emissions identified by EPA for the ammonia/urea production category were due to urea
application. Draft Inventory, pg. 4-11 (Table 4-11). EPA should act consistently throughout the
Draft Inventory and attribute emissions to categories only when that category generates the
emissions in question.
In addition, as industries are typically categorized in the U.S. by either Standard Industrial
Classification ("SIC") code or more currently - the North American Industry Classification
System ("NAICS"), and EPA tends to regulate using these classifications, this also seems a
logical way to characterize our industry. We also believe that the Intergovernmental Panel on
Climate Change ("IPCC") 2006 guidelines allow for this issue to be quantified in a manner
consistent with the regulatory structure inherent in the country the data are generated. Thus the
utilization of NAICS code 325311, for Nitrogenous Fertilizer Manufacturing, should pertain only
to manufacturing activities, as it is defined as:
(1) manufacturing nitrogenous fertilizer materials and mixing ingredients into fertilizers;
(2) manufacturing fertilizers from sewage or animal waste; and
(3) manufacturing nitrogenous materials and mixing them into fertilizers.2
In addition, we suggest that EPA utilize the NAICS definition for Nitrogenous Fertilizer
Manufacturing as seems to be the case with most other categories referenced.
Such an approach is embraced in the IPCC Good Practice Guidance and Uncertainty
Management in National Greenhouse Gas Inventories document wherein the IPCC states that the
greenhouse inventory "should contain neither over nor underestimates so far as can be judged,
and the uncertainties in these estimates should be reduced as far as practicable." IPCC Good
Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, pg.
2 htto://www.census. gov/epcd/ec97/def/325311 .TXT
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 10
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1.4. Therefore, we formally request that the reported amounts of CO2 emissions for the
Ammonia/Urea category be reduced accordingly (by 43%).
Another important point relates to Canada and their regulatory process surrounding greenhouse
gas emissions. Canada has proposed that CO2 emissions from the use of urea will not be covered
under their regulatory schemata and thus will not be attributed to nitrogen fertilizer
manufacturers. In addition, they have begun interaction with the IPCC to correct the
methodology of attributing C02 stored in urea to manufacturers.3 It is important as well to be
consistent within North America on the appropriate accounting regarding urea application.
In fact, given that a category already exists for Agricultural Soil Management (p. 2-11) which
includes exactly those emissions for all other crop inputs we are not clear why urea application
alone is attributed back to the ammonia manufacturing industry. Specifically, this category
includes, among other factors "Direct additions occur through the application of synthetic and
organic fertilizers; production of nitrogen-fixing crops and forages; the application of livestock
manure, crop residues, and sewage sludge; cultivation of high-organic-content soils; and direct
excretion by animals onto soil."
Further quoting, "Indirect additions result from volatilization and subsequent atmospheric
deposition, and from leaching and surface run-off of some of the nitrogen applied to or deposited
on soils as fertilizer, livestock manure, and sewage sludge." It seems clear that this category was
designed with the intent of capturing these emissions.
Therefore, we request that emissions associated with urea application be included in the
Agricultural Soil Management category.
Conclusion
TFI looks forward to working with EPA in developing an accurate Draft Inventory. We believe
that the issues we have raised must be address in the final Inventory Report. Should you have any
questions regarding our comments, please contact me at (202) 515-2706, or by email at
wcherz@tfi.org.
Sincerely yours,
William C. Herz
Vice President, Scientific Programs
3 PowerPoint Presentation: Natural Resources Canada (Adam Hendricks and Ken Olsen) to the Canadian Fertilizer
Institute, May 2005
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Comment 6
Alison M. Thomson—Joint Global Change Research Institute
March 28, 2007
RE: Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
Tom,
I've been able to review some of the draft inventory and have a couple of comments for you. In
general, the work is very solid and the methods and procedures are well established and
documented. I did not find any errors in methods or results.
My primary comment (section 7.3) is that my general understanding is that US agriculture is a
sink for C because of land being put aside in CRP, which is stated as a part of the reason for the
increase in Table 7.16. If possible, it would be very useful to know how much of this increase (is
it 5 or 50%?) is from which land use. Because, from my reading, I have the impression that when
you take CRP land out of the picture, US agriculture is still a source for C (on aggregate).
There has been discussion in the EPIC modeling community about the high sequestration
projected by Century when compared to the NRI based runs done by Steve Potter and others at
Blacklands Research Center in Texas.
Work that Cesar and I have done indicates that about 10-20% of the difference is due to soil
erosion, which is not considered in Century.
This is a long-winded way of saying I consider Century to be on the high end of the SOC
sequestration scale, therefore a breakdown of where conclusion that cropland is a sink is coming
from would be very helpful.
While the error checking and model verification sections are strong, it is lacking strong model
validation. P 7-24 mentions a validation with site specific data on lines 28-31, but no indication
of the results are given. The citation is there, and I think it would increase confidence in the
model to include a short description of the validation here.
All of my questions about the modeling were answered in the Annex sections, which I was able
to skim through but did not have time to review thoroughly. The structure of the land use
categories leads to redundancy, but I realize you don't have control over this aspect. In general, I
found it to be very well written.
Thanks for giving me the chance to participate,
Allison
Allison M. Thomson
Research Scientist
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 12
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Joint Global Change Research Institute*
8400 Baltimore Avenue, Suite 201
College Park, MD 20740
Phone: 301-314-6750
Fax:301-314-6760
Email: allison.thomson@pnl.gov
Web: http://www.globalchange.umd.edu
* A collaboration between the Pacific Northwest National Laboratory and the University of
Maryland, College Park.
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Comment 7
Bruce Steiner—American Iron and Steel Institute
March 28, 2007
Leif,
Following are a few comments on Section 4.2 (pages 4-6 - 4-10 of the draft report) relating to
Iron and Steel Production.
Page 4-6, line 29
Pig iron contains about 4% carbon, not 0.4%.
Page 4-7, line 15
"oxidized and the iron ore is reduced."
Page 4-7, lines 20-21
Emissions have not so much "fluctuated" as "declined steadily." And the reasons for the drop
are multitude, including restructuring of the industry, technological improvements, increased
scrap utilization, and emphasis on energy conservation. Domestic economic conditions have not
been a significant factor in recent years, and it is misleading to attribute changes to that factor or
to changes in the import/export mix.
Page 4-7, lines 34-35
Coking coal is not actually "consumed" at coke plants but rather is converted to coke. And
coking coal is not "produced" - coke is produced.
Page 4-8, line 1
Steel scrap has a carbon content of approximately 0.04%, not 0.4%. Moreover, it is not
"released" but rather is absorbed into the steel produced in the furnace.
Page 4-8, line 17
Steel carbon varies significantly, but 0.4% is much too high for an overall assumption. A better
factor is 0.04%, same as scrap steel.
General Comments
It is not clear whether all coal converted at all coke plants is used as a basis for calculating steel
industry emissions or only coal converted to coke for use in blast furnaces, the latter being the
more accurate. If the chapter is intended to include iron and steel foundries, however, it is fair to
assume all carbon from cokemaking is attributable to this category. In any event, however, not
all coke produced at U.S. coke plants goes to U.S. blast furnaces (and foundries) because some is
exported. Conversely, not all coke consumed in U.S. blast furnaces (or foundries) is produced in
the U.S. Rather than calculating emissions based on coal converted in coke plants, coke
consumption in blast furnaces (and possibly foundries) is the better metric.
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It is also not clear whether carbon dioxide emissions from BOF steel production is accounted for
separately (see entry in Table 4-9). Any C02 emitted from that process would already be
accounted for in the carbon in the pig iron from the blast furnace, which originates with the
carbon in the coal used to produce coke. Carbon in scrap would be offset by carbon in the steel
produced in a BOF.
Carbon emissions from sintering originate with carbon in the fuel used to support the sintering
process. If it is coke, it is already accounted for by the coke plant production value and should
not be counted again. If it is natural gas, it should be accounted for as a general energy source
and not attributable to iron and steel processing. Some carbon in sintering may also be
attributable to limestone or dolomite, but by the accounting rules used for this report (to be
revised when the 2006 IPCC methodology is adopted) suggest this carbon is attributable to the
minerals sector - in the same manner that limestone and dolomite usage in blast furnaces is not
accounted for in this report.
We have questions as to the legitimacy of the methane emission factors used for coke, pig iron,
and sinter production but have no alternative values to suggest. Intuitively, however, we cannot
envision fugitive emissions of methane from the blast furnace for pig iron production or in the
sintering process.
We believe the use of methodologies described in the 2006 IPPC guidance will present a much
more accurate picture of steel industry GHG emissions.
Happy to talk through some of this if you wish.
Bruce Steiner
Comment 8
Bruce Steiner—American Iron and Steel Institute
March 29, 2007
Mausami,
I hereby retract my claim that steel contains 0.04% carbon. I was thinking in terms of low-
carbon steels, which can have contents that low. Carbon contents vary widely, but the 0.4%
figure in your text is probably a good average for inventory purposes. See
http://en.wikipedia.org/wiki/Carbon steel or http://www.kev-to-steel.com/Articles/Art62.htm. If
you would rather not use a website reference, I can fax you some pages from the steel manual
called 'The Heating, Treating & Shaping of Steel' tomorrow. I apologize for the false alarm on
the number.
Steel scrap, of course, would have the same carbon contents as steel - also highly variable - but
0.4% would be a good average there also.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 15
Sinks: 1990-2005
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However, I stand by the comment that carbon content of scrap coming into the steelmaking
furnace is offset by the carbon content of the steel being produced in that furnace, so it doesn't
make sense to count the carbon in scrap as an emission.
Call if you wish to discuss further. I'll be in and out of meetings all day Friday.
Bruce
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and
Sinks: 1990-2005
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Comment 9
Ozz/e Morris—The Mosaic Company
March 29, 2007
The Draft Inventory Does Not Recognize 'Off-Sets' for Using 'Waste' Heat
Mosaic believes that the Draft Inventory should recognize the efforts by phosphoric acid
production manufacturers to utilize 'waste heat' that would otherwise be vented to the atmosphere
and reduce reported greenhouse gas emissions accordingly. This applies both to the production
of phosphate fertilizer and nitric acid. The majority of phosphoric acid production in the U.S. is
by the 'Wet Process' that utilizes sulfuric acid in the chemical reactions described on page 4-24
of the draft Inventory. The waste heat in sulfuric acid production is recaptured and utilized to
generate electricity and as a direct off-set to use of other energy sources. This beneficial reuse
scenario truly represents green energy and should be recognized and encouraged by EPA and, as
such, addressed in the Draft Inventory.
Mosaic's Sulfuric Acid operations produce approximately 123.5 KWH of electricity per ton of
sulfuric acid produced. This is accomplished by capturing 'waste heat' from a fuel source that
does not produce any greenhouse gases. Phosphoric Acid production, due to the need for
sulfuric acid and investments in heat recovery and electricity production, off-sets over 3200
times the amount of Carbon Dioxide that process emits. Mosaic believes this estimate is
generally representative for the U.S. phosphoric acid industry and is representative of the offsets
that should be recognized on the energy side of the Draft Inventory.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 17
Sinks: 1990-2005
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Comment 10
Miyun Park—The Humane Society of the United States
March 29, 2007
RE: Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
The Humane Society of the United States (The HSUS), the nation's largest animal protection
organization, representing nearly 10 million members and constituents, welcomes the
opportunity to submit comments to the U.S. Environmental Protection Agency (EPA) regarding
its Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005 (Draft Inventory).
The HSUS is encouraged that the EPA recognizes that some greenhouse gas (GHG) emissions
can be directly attributed to industrialized animal agriculture practices. Specifically, the agency
notes that the primary reason for the overall increase in methane emissions is the shift towards
housing pigs and cows used for the dairy industry in larger facilities that use liquid manure
management systems.1 Similarly, the agency notes that the overall increase in nitrous oxide
emissions is largely due to changes in the poultry industries, namely the shift toward litter-based
manure management systems, confinement in high-rise houses, and an overall increase in the
U.S. poultry population.2
While the Draft Inventory accounts for animal agriculture industries' direct GHG emissions
through enteric fermentation and manure management,3 the agency does not identify all GHG
emissions attributable to animal agriculture industries. The agency notes that carbon dioxide
(CO2) emissions due to some land-use activities and on-farm energy use are accounted for in the
chapter on "Land Use, Land-Use Change, and Forestry" and the chapter on "Energy,"
respectively.4 Nevertheless, these chapters do not apportion agriculture's contributions to CO2
emissions, nor do they disaggregate animal agriculture's contributions to these C02 emissions.
Finally, the Draft Inventory does not seem to account for CO2 emissions resulting from
deforestation for grazing; packaging, transporting, and applying nitrogen fertilizer for feedcrops;
or energy used in processing facilities and for transportation of live animals and end products.
In contrast to the Draft Inventory, a recent report by the Food and Agriculture Organization
(FAO) of the United Nations evaluates the many environmental impacts of animal agriculture
industries, including GHG emissions. Livestock's Long Shadow: Environmental Issues and
Options more comprehensively and accurately takes into account both their direct impacts and
the impacts of feedcrop agriculture and deforestation for grazing.5
1 U.S. Environmental Protection Agency. 2007. Inventory of U.S. greenhouse gas emissions and sinks: 1990 - 2005.
Draft for public review, p. 6-7. February 20. www.epa.gov/climatechange/emissions/downloads07/07CR.pdf.
Accessed March 12, 2007.
2 Ibid.
3 Ibid, p. 6-1.
4 Ibid.
5 Steinfeld H, Gerber P, Wassenaar T, Castel V, Rosales M, and De Haan C. 2006. Livestock's long shadow:
environmental issues and options (Rome: Food and Agriculture Organization of the United Nations, p. xx; p. 83).
virtualcentre.org/en/library/key_pub/longshad/A0701E00.pdf. Accessed February 19, 2007.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 18
Sinks: 1990-2005
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The FAO has concluded that, on a global scale, animal agriculture industries are responsible for
more GHG emissions (measured in CO2 equivalent) than the share contributed by
transportation.6 Animal agriculture industries are responsible for 9% of C02 emissions,7
accounting for sources such as on-farm fossil fuel use for lighting, temperature control,
automated machinery, and ventilation (90 million tons per year);8 packaging, transporting, and
applying nitrogen fertilizer for feedcrops (more than 40 million tons per year);9 and deforestation
for grazing (2.4 billion tons per year).10
The HSUS requests that the EPA amend the Draft Inventory to identify the portion of C02
emissions attributable to the following aspects of animal agriculture industries:
• Feedcrop agriculture, including packaging, transporting, and applying nitrogen fertilizer
for feedcrops
• Deforestation for grazing
• Energy used on-farm, including energy used for lighting, temperature control, automated
machinery, and ventilation
• Energy used in processing facilities
• Energy used for transportation of live animals and end products
Thank you for your consideration.
Sincerely,
^
Miyun Park
Vice President, Farm Animal Welfare
The Humane Society of the United States
6 Ibid, p. xxi.
7 Ibid.
8 Ibid, pp. 88-9
9 Ibid, p. 88).
10 Ibid, p. 90.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 19
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Comment 11
Patrick F. Mahoney—Energy Answers International
March 29, 2007
Re: Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
Dear Mr. Hockstad,
I have reviewed the Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
and would like to provide the following comments and information for your consideration.
The report indicates that methane emitted from landfills makes up 25% of the nation's methane
emissions, and waste deposited at a landfill is expected to continue releasing methane for 10 to
60 years. Having identified landfills as a major source of greenhouse gases, I encourage the EPA
to begin actively supporting resource recovery / waste-to-energy as an environmentally sound
alternative.
I have attached the technical paper by Alan Eschenroeder, Ph.D. of the Harvard School of Public
Health entitled Greenhouse Gas Dynamics of Municipal Solid Waste Alternatives. His extensive
research and analysis concludes that "the replacement of landfills with municipal waste
combustors significantly reduces greenhouse gas impacts." Significant cuts in the three most
important gases — carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOx) can be
achieved by eliminating landfills as the primary disposal point for solid waste and replacing
fossil fuels with renewable energy sources including solid waste.
The European Union Landfill Directive, which essentially requires the phase-out of landfills for
organics and other carbon containing materials by 2016 and will impose severe penalties for non-
compliance, will have a dramatic impact on lowering greenhouse gas emissions. According to a
study carried out by the Oko-Institute on behalf of the German Federal Environment Agency
(UBA) and the Federal Environment Ministry (BMU), "The application of the Landfill Directive
will save approximately 74 million tons CO2 equivalents by 2016, thanks to avoided landfill gas
(methane) emissions." "The study estimates that the saving of C02 equivalents could increase to
134 million tons if a landfill ban on unpretreated waste would be implemented across Europe."
This study and other information which documents the EU's enlightened view of solid waste
management can be downloaded from the Confederation of European Waste to Energy Plants
website (www.cewep.com). The CEWEP website also presents a chart of the taxes and fines
levied by governments throughout Europe to encourage waste producers to divert material from
landfills and make recycling and combustion with energy and materials recovery a more viable
option.
The March, 2007 article which I have attached entitled Reduce CO2? Build Incinerators!
concludes that "an ambitious European waste policy, with a balanced package of measures for
prevention, re-use and thermal treatment of residual waste, will make a substantial contribution
to reducing greenhouse C02 emissions." I encourage the EPA to analyze the data which has
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 20
Sinks: 1990-2005
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supported the EU's efforts to minimize the use of landfills in favor of more environmentally
sensitive options.
I also would like to comment that, since 1976 with the passage of the RCRA, the EPA has
chosen to impose stringent air emission standards on waste-to-energy / resource recovery
facilities while not requiring any gas monitoring, collection or treatment systems for landfills.
The rationale for this inequity should be examined.
Energy Answers Corporation has more than 25 years of experience in environmental
management of solid waste with a successful record of recovering recyclable material and energy
from materials which otherwise would be landfilled. Our website (www, energy answers, com)
details our technology and "zero disposal" objective and the recognition and awards we have
received from the American Academy of Environmental Engineers, Ecological Society of
America, Smithsonian Institute and other organizations which have acknowledged our
contributions to environmentally and economically sound waste management.
Thank you for the opportunity to comment and provide this information for your consideration.
Sincerely,
Patrick F. Mahoney, P.E., D E E.
President
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 21
Sinks: 1990-2005
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Comment 12
Glen P. Kedzie—American Trucking Associations, Inc.
March 29, 2007
Comments of the American Trucking Associations, Inc. On the Inventory of U.S. Greenhouse
Gas Emissions and Sinks: 1990-2005
Introduction
The American Trucking Associations, Inc. (ATA), with offices at 2200 Mill Road, Alexandria,
Virginia 22314-4677, is the trade association that represents the U.S. trucking industry.1 As the
national representative of the trucking industry, ATA is vitally interested in matters potentially
affecting the nation's motor carriers. For this reason, ATA is submitting these comments in
response to the agency's Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005.
The trucking industry is composed of both large national enterprises as well as a host of
small businesses, all of whom operate in extremely competitive business environments, with
narrow profit margins. According to the Department of Transportation, fully 97% of motor
carriers (roughly 1,000,000 in number) have 20 or fewer trucks. For small carriers in particular,
their livelihood can be dramatically impacted by new requirements such as those that may be
imposed through the implementation of a greenhouse gas regulatory regime. In its capacity as the
representative of the trucking industry, ATA regularly comments on matters affecting the
national trucking industry's common interests, providing its expertise and understanding of the
industry to help avoid unreasonable, inappropriate and/or unduly burdensome regulatory or
legislative requirements.
Comments
A greater distinction is needed among the categories of transportation and mobile sources. In
the report's most commonly read section, the Executive Summary, Table ES-2 includes
transportation and mobiles sources under the broad categories of "Fossil Fuel Combustion" and
"Mobile Combustion". In Tables ES-3, ES-7 and ES-8, 2005 greenhouse gas (GHG) emissions
from the transportation sector range from 1,899.5 Tg CC^Eq. to 2,015.8 Tg CC^Eq. Little
discussion is provided explaining why emissions from the transportation sector are different in
each of the tables. Based on these tables, the entire transportation sector is estimated to account
for 26 to 28 percent of total U.S. GHG emissions.
To try and understand these estimates in more detail, Chapter 3 - Energy includes a
section titled Transportation End-User Sector which corresponds with the low-end estimate
contained in the Executive Summary. In Table 3-7, transportation end-users are classified by
vehicle {i.e., automobile, light-duty truck, other truck, etc.) and fuel {i.e., gasoline, distillate fuel
oil, jet fuel, etc.) type. This table is the first indication that gasoline vehicles contribute more than
62 percent of GHG emissions from the transportation sectors. However, no explanation is
provided as to differences among the types of vehicles listed. For example, what constitutes a
"light-duty truck" versus the category of "other truck" is never explained in this chapter.
1 ATA is a united federation of motor carriers, state trucking associations, and national trucking conferences created
to promote and protect the interests of the trucking industry. Its membership includes more than 1,700 trucking
companies and industry suppliers of equipment and services. Directly and through its affiliated organizations, ATA
represents over 34,000 companies and every size, type and class of motor carrier operation.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 22
Sinks: 1990-2005
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Only by working through the documentation contained in Annex 3 can one gain a better
understanding of the emission estimates attributed to the transportation sector. For example, by
reading footnote 24 you learn that the term "heavy-duty truck" includes vehicles that are
sometimes classified as medium-duty trucks (those with a GVWR between 8,500 and 14,000
lbs.). Table A-108 estimates 385.8 Tg CC^Eq. for medium/heavy-duty trucks. This total is
slightly more than the total attributed to the "other truck" category in Chapter 3. Again, why
these differences exist is never explained.
In comparing Table A-108 to Table A-l 11, GHG Emissions from Domestic Freight
Transportation, trucking is estimated to account for 385.8 Tg CC^Eq. (which is the same total
attributed to the medium/heavy-duty truck category in Table A-108). Since it is unlikely that all
medium/heavy-duty trucks are involved in trucking, it is difficult to determine how much of this
total should actually be allocated to the trucking industry.
Another example as to where further sector emission breakdowns is warranted appears in
Figure ES-16. Aviation is broken out as a separate mobile combustion category while the rest of
the mobile source categories are lumped together under the overly-large category Road & Other.
Different mobile sectors vary significantly in their GHG footprints. For instance, in terms of
"overall" transportation GHG emissions, trucks contribute less than one-third the GHG of
passenger vehicles (19% versus 60%). Passenger cars, light-duty trucks and motorcycles
contribute 16.5% of all U.S. GHG emissions compared to 5.3% from medium and heavy-duty
trucks. The stark difference between the auto industry's GHG's and trucking's GHG footprint
needs to be clearly depicted in all figures and tables contained in the inventory. Given the stark
differences between the functionality of on-road users, ATA further requests that busses be
categorized as a separate transportation subsector.
Conclusion
ATA appreciates the difficulties associated with developing a comprehensive GHG
emissions inventory of this scale and magnitude. However, given the high level of attention
focused on this issue, it is imperative that a comprehensive and well-documented inventory be
presented. While transportation may be a commonly defined sector, clearly identifying both
sector and sub-sector GHG emission contributions will assist both Congress and industry in
discussing how to approach and implement any proposed regulatory measure.
Incorporating defined transportation subcategories, such as passenger transportation,
medium/heavy-duty trucks, aviation, busses, etc. (as opposed to listing the entire sector as
"Transportation" or "Fossil Fuel Combustion") in the same context as other sources of GHG
emissions, will help provide a better understanding of the sources and GHG emission levels
associated with specific transportation sub-sectors.
Respectfully submitted,
Glen P. Kedzie
Assistant General Counsel & Environmental Counsel
Law & Regulatory Affairs
American Trucking Associations, Inc.
2200 Mill Road
Alexandria, VA 22314-4677
E-mail: gkedzie@trucking.org
Phone: 703-838-1879
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 23
Sinks: 1990-2005
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Comment 13
Ted Michaels—Integrated Waste Services Association
March 28, 2007
RE: Comments on Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-
2005
Dear Mr. Hockstad:
On behalf of the Integrated Waste Services Association (IWSA), I am submitting comments on
EPA's Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005. IWSA is the
national trade association representing companies and local governments engaged in the waste-
to-energy industry. IWSA has a vested interest in EPA's draft inventory since waste-to-energy is
an important tool in reducing greenhouse gas emissions, namely carbon dioxide and methane, on
a nationwide basis.
There are 88 waste-to-energy plants operating in 26 states managing about 29 million tons of
America's trash each year. Studies utilizing EPA's Municipal Solid Waste Decision Support
Tool show that waste-to-energy is a net negative emitter of greenhouse gases and is the best post-
recycled waste management option with respect to reducing greenhouse gas emissions.
Our comments specifically relate to two sections of EPA's draft report - Municipal Solid Waste
Combustion (Section 3.9 and Annex 3.6), and Landfills (Section 8.1 and Annex 3.14).
Attachment 1 to this letter contains our detailed comments, and Attachments 2 and 3 contain two
key documents, the Biocycle article (Simmons et al. 2006) frequently referenced herein, and a
nitrous oxide emission test report (Avogadro 2007). So the reader does not miss our main points
when reviewing the detailed comments, we have summarized them here:
1. The draft report over-estimates the amount of municipal solid waste (MSW) combusted
by 31% when properly compared to the amount documented by Biocycle (Simmons el al.,
2006). Values for total waste combusted in the draft report result from the mistaken use
of the Biocycle data. EPA should correct these values;
2. Biocycle waste reports are credible and endorsed by the EPA Office of Solid Waste and
others. Industry and the Department of Energy/Energy Information
3. Administration data support the Biocycle data. The draft report inappropriately relies on
data from the Characterization of Municipal Solid Waste in the United States report
series, also known as the Franklin reports (e.g., USEPA 2006). The Franklin reports
seriously understate the total MSW discards and amount landfilled; as a result, the
proportion of plastics and other fossil derived waste components assumed to be sent to
combustion is over-stated. EPA should rely on waste generation, combustion, and
landfilling data from Biocycle to estimate the total discards and the proportion of
components that are combusted;
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 24
Sinks: 1990-2005
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4. The draft report significantly over-estimates the amount of C02 emitted by municipal
solid waste (MSW) combustion. The main cause of this over-estimate is reliance on the
aforementioned Franklin report data, which EPA should change;
5. The draft report mistakenly gives the reader the impression that C02 emissions from tire
combustion occur at waste-to-energy facilities. EPA should clarify that, of the tires
disposed via combustion, the vast majority is combusted as tire derived fuel (TDF) in
other types of plants such as cement kilns, pulp and paper plants, industrial/utility boilers,
and dedicated tire-to-energy plants;
6. The draft report relies on older, foreign data to estimate N20 emissions from MSW
combustion. EPA should re-examine N20 emissions based on recent test data we are
providing, and conclude that modern waste-to-energy facilities are not significant sources
on N20 emissions; and,
7. The draft report fails to recognize the high degree of uncertainty regarding methane
emissions from landfills. EPA should review its uncertainty analysis for landfills, as data
suggest that the errors associated with LFG methane estimates are greater than the
uncertainty range given in the report.
IWSA has invested considerable effort in our detailed critique of the draft report and is confident
of our conclusions. For example, we have estimated total waste-to-energy CO2 emissions using
an independent simplified method, as presented in the comments, and it reinforces our
conclusion that EPA over-estimated emissions in the draft report by at least a factor of two.
Thank you for consideration of our comments. IWSA is available to discuss this information at
your convenience, and looks forward to working with the Agency on this important issue.
Sincerely,
Ted Michaels
President
Attachment 1
IWSA Comments on EPA's Draft U.S. Greenhouse Gas Inventory Report
General Comments:
EPA's draft report significantly over-estimates the amount of C02 emitted by municipal solid
waste (MSW) combustion. It uses the wrong database (the Franklin reports) to quantify MSW
generation, discards, and landfilling, and the proportion of fossilcontaining plastics and other
discards sent to combustion. EPA should use a more accurate database (Biocycle reports),
presently endorsed by other agencies, to estimate the total discards and the proportion of fossil
components that are combusted.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 25
Sinks: 1990-2005
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The draft report also fails to recognize the high degree of uncertainty regarding methane
emissions from landfills. Virtually any technical paper that addresses landfill gas generation,
collection and management identifies uncertainties. According to EPA's own documentation
there are error sources; however the origin of the -39 to +32 % error band is never provided in
the draft report. IWSA does not have access to the data necessary to quantify this error range;
however the EPA should present the facts, assumptions and analysis for calculation of error.
Specific Comments:
Comment 1. EPA's draft report significantly overstates the quantity of MSW combusted
for the years 2001 through 2005. (Section 3.9, page 3-50, line 33; Section 3.9, page 3-52,
Table 3-45; Annex 3.6, page A-149, Table A-136.)
The draft report bases MSW combustion quantities on Biocycle's State of Garbage in America
survey (Simmons et al., 2006). This biennial survey is rightfully recognized as a credible source
of MSW generation, recycling, and disposal data because it obtains MSW data directly from
state agencies responsible for its management. However, EPA incorrectly applied the Biocycle
data for the years 2002 and 2004, which in turn affected the interpolated values for 2001, 2003,
and 2005. As a result, the 2001-2005 values in Table A-136 attributed to Biocycle data are
actually inflated by as much as 31%. Consider, for example, the year 2004. Table 4 of the
Biocycle paper (Simmons et al, 2006) directly reports the total nationwide amount of MSW
combusted as 28,860,545 short tons, equivalent to 26,182,285 metric tons. Yet Table A-136 of
the draft report states that 34,181,035 metric tons were combusted in 2004, a value 31% higher
than the stated Biocycle quantity (34,181,035 / 26,182,285 = 1.31).
We think we understand the source of the discrepancy. Starting with the year 2002 (which also
affects the interpolated 2001 value) Biocycle began reporting the "MSW Generated" figures
using a different methodology. See Themelis and Kaufman (2004) for a complete explanation.
EPA apparently did not take this methodology change into account when calculating the MSW
combusted quantities. Specifically, EPA incorrectly calculated the amount of MSW combusted
by using Table 1 "Reported MSW Generation" and "MSW Waste-to-Energy" columns as
follows:
509,155,516 short tons x 7.4%
= 37,677,508 short tons, or 34,181,035 metric tons
To be correct, EPA should have calculated the combusted amount using the "MSW Generated"
and "MSW Waste-to-Energy" columns in Table 1, which yields 26,037,823 metric tons, nearly
the same as the Biocycle value reported in Table 4. (The small difference is due to rounding
error; the actual combustion percentage is 28,860,545/387,855,461 = 7.44% versus 7.4% shown
in Table 1.)
Other independent sources on information confirm the appropriateness of the lower value of
MSW disposed of at waste-to-energy facilities. The 2004 IWSA Directory of Waste-to-Energy
Plants (Kiser and Zannes, 2004) reports annual MSW capacity as 28.7 million short tons,
equivalent to 26.0 million metric tons.
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The Department of Energy, Energy Information Administration (DOE/EIA) 906/920 reports also
report WTE facility throughputs (DOE/EIA 2007). Reported 2004 throughput for the "MSW"
fuel type was 26,643,163 metric tons, again consistent with the lower, correct values based on
Biocycle data.
The DOE/EIA 906/920 report is credible. Comparing the list of facilities reporting in the
DOE/EIA report with those in the IWSA directory shows that roughly 98% of the WTE capacity
is accounted for in the DOE/EIA report.
Comment Table 1 compares EPA's draft report MSW combustion quantities with the correct
Biocycle quantities and DOE/EIA report quantities for the years 2001-2005. EPA should correct
Table A-136, Table 3-45, and associated text to be consistent with the correct Biocycle data
given in this table.
Comment Table 1. MSW Combustion in U.S. (metric tons)
Correct Values from
Incorrect Draft Values Based DOE/EIA
Report Values on Biocycle 906/920
Year From Table A-136 Data Reports
2001
29,732,255
25,888,947
26,244,229
2002
33,723,677
25,802,917
27,700,143
2003
33,970,308
25,920,370
26,922,210
2004
34,181,035
26,037,823
26,643,163
2005
34,181,035
26,037,823
26,719,089
IWSA proposes that EPA remove the first column in Table A-136 called "EPA". Data in this
column are based on the Characterization of Municipal Solid Waste in the United States series of
reports, also known as the Franklin reports (e.g., USEPA 2006). As discussed below, we
question the use of these reports in general. In the case of MSW combustion quantities, Franklin
claims to use industry data, but examination of its methodology shows they incorrectly cite
capacity data from IWSA's directory, effectively double-counting waste sent to refuse derived
fuel facilities, and include combustion of tire-derived fuel and other separated wastes in the total
reported quantities (USEPA 2006, pp. 137-138). If desired, EPA should use the DOE/EIA
906/920 Report database for comparative purposes in Table A-136.
Comment 2. EPA should avoid using data from the Characterization of Municipal Solid
Waste in the United States report series (e.g., USEPA 2006), deferring to these reports only
when no sources of direct information are available. (Section 3.9; Annex 3.6)
These reports, prepared by Franklin Associates, use the "materials flow methodology" in which
nationwide MSW quantity and composition are not directly measured, but rather calculated using
production data and material balances. This method has been shown to significantly
underestimate the total quantity of MSW generated and landfilled when compared with methods
that rely on direct measurement and reporting (Themelis and Kaufman 2004). EPA itself is
avoiding use of the Franklin MSW quantities in Section 8 (Landfills) of the draft report, opting
instead to use the Biocycle data (Simmons et al. 2006) which is based on direct input from State
regulatory agencies. The following comment table shows the degree of the error associated with
the Franklin reports:
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 27
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Comment Table 2. Comparison of Franklin and Biocycle Data
Franklin Biocycle Difference
(million (million (million
Difference
Year MSW Data tons) tons) tons)
(%)
2002
Total Generated
235.5
369.4
133.9
56.9%
Total Discards
165.0
270.8
105.8
64.1%
Total Landfilled
131.7
242.3
110.6
84.0%
2004
Total Generated
247.3
387.9
140.6
56.9%
Total Discards
169.6
277.3
107.7
63.5%
Total Landfilled
135.5
248.6
113.1
83.5%
Given the significant under-estimates of total MSW quantities, any MSW compositional
information derived from Franklin reports must also be considered suspect, and used with
discretion.
IWSA wants to emphasize the basis for preferring the Biocycle data:
1. The annual numbers are similar to those generated by industry when preparing regulatory
reports;
2. Data are comparable to those reported by DOE/EIA; and,
3. Data from a regulatory agency that is responsible for MSW management is a direct and
accountable source of data versus the indirect manufacturing data used in the Franklin
reports.
Waste-to-energy facilities are throughput limited (unlike landfills) and weigh MSW deliveries as
a regulatory reporting requirement. Given the finite number of facilities (88), it is not very
difficult to track total waste-to-energy industry performance with reasonable accuracy.
EPA assigns confidence ratings (A through E) to emission factors given in AP-42 (USEPA
1998). IWSA proposes that a similar methodology is appropriate here. When data are based on
direct measurements (such as WTE facility MSW annual throughput), then they should be
assigned a high confidence rating. Data based on other methods, such as the Franklin reports,
should be assigned a lower grade. The error in the Franklin data is in the 40 to 80 % range. This
type of error would seem to warrant a low confidence rating.
Comment 3. EPA's draft report significantly over-estimates the quantity of plastics
combusted and the resulting amount of C02 emitted. (Section 3.9, page 3-51, Tables 3-43
and 3-44; Annex 3.6, page A-145, Tables A-129 and A-130)
Annex 3.6, Table A-129 presents the quantities of various plastics generated, recovered, and
discarded based on Franklin report information. EPA's method for estimating CO2 emissions
from the combustion of plastics is of the form:
C02 = X * Y * Z
Where:
X = total amount of plastic in MSW discards
Y = fraction disposed of by combustion
Z = plastics carbon content
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 28
Sinks: 1990-2005
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The Franklin data regarding the amount of plastics contained in MSW discards ("X") and the
specific carbon content of those plastics ("Z") may or may not be valid; to our knowledge no
comprehensive direct measurement data exist. However, the proportion of discards sent to
landfill (80%) and combustion (Y= 20%) are clearly incorrect. The proportion of discards
landfilled and combusted should be based on Biocycle data, which EPA has embraced in other
sections of this draft report. EPA should not use the flawed Franklin data which has been shown
to seriously under-estimate total discards and landfilled quantities, and has never been shown to
be an accurate indicator of field data. Comment Table 3 shows the proportion of MSW discards
combusted and landfilled based on the Biocycle data (Simmons et al. 2006, Table 1). EPA should
use these data to calculate the quantities of plastics combusted for the years 1990-2005.
Comment Table 3. Proportion of MSW Discards Combusted and
Landfilled.
Year Combusted Landfilled Notes
1990
13.0%
87.0%
1991
11.6%
88.4%
1992
13.3%
86.7%
1993
12.3%
87.7%
1994
13.0%
87.0%
1995
13.7%
86.3%
1996
13.9%
86.1%
1997
12.9%
87.1%
1998
10.9%
89.1%
1999
10.4%
89.6%
2000
10.3%
89.7%
2001
10.4%
89.6%
Interpolated
2002
10.5%
89.5%
2003
10.4%
89.6%
Interpolated
2004
10.3%
89.7%
2005
10.3%
89.7%
Same as 2004
As a result of these corrected proportions, Tables A-129 and A-130 should be revised as shown
below. (NOTE: Revised Table A-129 values are in Gg. Table A-129 values in the draft report are
stated to be in Gg, but the values are actually in thousand short tons, as given in Table 7 of the
Franklin report (USEPA 2006, page 50)).
Revised Table A-129: 2005 Plastics in the Municipal Solid Waste Stream by Resin (Gg)
Waste
Pathway
PET
HDPE
PVC
LDPE/
LLDPE
PP
PS
Other
Total
Generation
2,595
5,343
1,488
5,851
3,629
2,350
4,971
26,227
Recovery
490
472
0
172
9
0
354
1,497
Discard
2,105
4,872
1,488
5,679
3,620
2,350
4,618
24,730
Landfill
1,887
4,367
1,334
5,091
3,245
2,106
4,140
22,171
Combustion
218
504
154
588
375
243
478
2,559
Recovery*
19%
9%
0%
3%
0%
0%
7%
6%
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 29
Sinks: 1990-2005
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Discard*
81%
91%
100%
97%
100%
100%
93%
94%
Landfill*
73%
82%
90%
87%
89%
90%
83%
85%
Combustion*
8%
9%
10%
10%
10%
10%
10%
10%
*As a percent of waste generation
Revised Table A-130: 2005 Plastics Combusted (Gg), Carbon Content (%), Fraction Oxidized
(%) and Carbon Combusted (Gg)
Factor
PET
HDPE
PVC
LDPE/
LLDPE
PP
PS
Other
Total
Quantity Combusted
218
504
154
588
375
243
478
2,559
Carbon Content of Resin
63%
86%
38%
86%
86%
92%
66%
Fraction Oxidized
98%
98%
98%
98%
98%
98%
98%
Carbon in Resin
Combusted
134
425
57
495
316
219
309
1,956
Emissions (Tg C02 Eq.)
0.5
1.6
0.2
1.8
1.2
0.8
1.1
7.2
These revisions reduce the 2005 estimated C02 emissions from plastics combustion from 13.9
Tg C02Eq to 7.2 Tg C02Eq. EPA should revise Tables 3-43 and 3-44 for all reporting years
accordingly.
Comment 4. EPA's draft report significantly over-estimates the quantity of synthetic
rubber combusted and the resulting amount of C02. (Section 3.9, page 3-51, Tables 3-43
and 3-44; Annex 3.6, page A-147, Table A-133)
This comment is similar to the above comment regarding plastics. EPA used the same
methodology to estimate the quantity of synthetic rubber in combusted MSW, and it too suffers
the same inaccuracy as the plastics. Again, using the Biocycle data to determine the proportion of
discards combusted (10.3%), the amount of synthetic rubber combusted in 2005 is 370 Gg,
derived as follows:
Comment Table 4. Calculation of Rubber and Leather to Combustion
in 2005
Total
Discards
Discards*
Total
Combusted
Combustion
Product Type
(000 tons)
(Gg)
(%)
(Gg)
Durables (not Tires)
2920
2,649
10.3%
274
Non-Durables
Clothing and Footwear
700
635
10.3%
66
Other Non-Durables
290
263
10.3%
27
Containers and Packaging
30
27
10.3%
3
Total
3940
3,574
10.3%
370
Total Discards from USEPA (2006), Table 8.
Table A-133 should be revised as shown:
Revised Table A-133: Rubber and Leather in Municipal Solid Waste in 2005
Synthetic Carbon Fraction
Combustion Rubber Content Oxidized
Emissions
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 30
Sinks: 1990-2005
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Product Type (Gg) (%) (%) (%)
(Tg
C02Eq.)
Durables (not Tires)
274
100%
85%
98%
0.8
Non-Durables
Clothing and Footwear
66
25%
85%
98%
0.1
Other Non-Durables
27
75%
85%
98%
0.1
Containers and Packaging
3
100%
85%
98%
0.0
Total
370
1.0
These revisions reduce the 2005 estimated C02 emissions from synthetic rubber combustion
from 1.9 Tg C02Eq to 1.0 Tg C02Eq. EPA should revise Tables 3-43 and 3-44 for all reporting
years accordingly.
Comment 5. EPA's draft report significantly over-estimates the quantity of synthetic fibers
combusted and the resulting amount of C02. (Section 3.9, page 3-51, Tables 3-43 and 3-44;
Annex 3.6, page A-148, Tables A-134)
Again, this comment is similar to the above comment regarding plastics. EPA used the same
methodology to estimate the quantity of synthetic fibers in combusted MSW, and it contains the
same inaccuracy. This inaccuracy should be corrected by using the Biocycle data to determine
the proportion of waste combusted. Table A-134 should be revised as follows:
Revised Table A-134: Textiles in MSW
(Gg)
%
Year
Generation
Recovery
Discards
Combusted*
Combustion
1990
2884
328
2556
13.0%
332
1991
3008
347
2661
11.6%
309
1992
3286
387
2899
13.3%
384
1993
3386
397
2989
12.3%
369
1994
3604
432
3172
13.0%
412
1995
3674
447
3227
13.7%
442
1996
3832
472
3360
13.9%
467
1997
4090
526
3564
12.9%
458
1998
4269
556
3713
10.9%
407
1999
4498
611
3887
10.4%
406
2000
4686
640
4046
10.3%
417
2001
4870
715
4155
10.4%
432
2002
5093
740
4353
10.5%
457
2003
5257
755
4502
10.4%
469
2004
5371
849
4522
10.3%
468
2005
5530
844
4686
10.3%
485
*From Biocycle (Simmons et al. 2006)
In addition, we believe EPA made a mistake calculating the C02 emissions for synthetic fibers
found in Tables 3-43 and 3-44. We used the equation on page A-147 and were unable to
duplicate EPA's values. The correct C02 calculation for 2005 is as follows: 485 Gg fibers
combusted x 55% synthetic x 70% carbon x 44/12 x 0.001 = 0.7 Tg C02Eq.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 31
Sinks: 1990-2005
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These revisions reduce the 2005 estimated C02 emissions from synthetic fiber combustion from
2.4 Tg C02Eq to 0.7 Tg C02Eq. EPA should revise Tables 3-43 and 3-44 for all reporting years
accordingly.
Comment 6. EPA should clarify that MSW combustion facilities do not combust significant
quantities of tires and that C02 from tire combustion is attributable to other industry
sectors. (Section 3.9, page 3-50, lines 30-32; Annex 3.6, page A-145)
We agree with the statement on page 3-50 that tire disposal practices differ from other MSW.
Tires are usually collected and managed as a separate waste stream, appearing in very small
quantities in the MSW delivered to waste-to-energy facilities. For example, as the operator of 31
waste-to-energy facilities in the United States, Covanta Energy Corporation does not solicit tires
as a discrete waste stream because of generally unfavorable economics, and does not process
bulk loads of tires because the operating problems they can create.
Section 3.9 gives the reader the impression that C02 emissions from tire combustion occur at
waste-to-energy facilities. In fact, of the tires disposed via combustion, the vast majority is
combusted as tire derived fuel (TDF) in other types of plants such as cement kilns, pulp and
paper plants, industrial/utility boilers, and dedicated tire-to-energy plants. (RMA 2006)
EPA should clarify in the text and in Tables 3-43, 3-44 that C02 from tire combustion is
attributable to other types of industries.
Comment 7. EPA should correct Tables 3-43 and 3-44 to be consistent with the above
comments. (Section 3.9, page 3-51, Tables 3-43 and 3-44)
The following table shows the net effect of the above comments on the emissions of C02 from
MSW combustion:
Comment Table 5. 2005 C02 Emissions from MSW Combustion (Tg
C02 Eq.)
Gas/Waste Product
Draft
Report
2005
Corrected
2005
Notes
C02
21.0
11.7
Plastics
13.9
7.2
Comment 3
Synthetic Rubber in Tires*
1.2
1.2
Comment 6
Carbon Black in Tires*
1.6
1.6
Comment 6
Synthetic Rubber in MSW
1.9
1.0
Comment 4
Synthetic Fibers
2.4
0.7
Comment 5
*Emissions attributed to non-waste industries
Accordingly, EPA should re-calculate and revise Tables 3-43 and 3-44 for all reported years.
The Reasonableness of Our Comments and Revised Emissions Estimates
Whenever complicated analyses are used to derive information, it is prudent to have an
independent, simplified approach to use as a "validation check". In the case of MSW combustion
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 32
Sinks: 1990-2005
-------
at WTE facilities, such an approach is readily available. The total (biogenic and non-biogenic)
amount of C02 emitted from MSW combustion at waste-to-energy facilities is the product of
MSW combustion throughput and the MSW C02 factor, both known with good accuracy. For
2005, MSW throughput was 26,037,823 metric tons (Simmons et al. 2006). The MSW C02
factor is calculated from EPA's MSW Fc factor of 1820 scf C02/MMBTU (40 CFR 60,
Appendix A, Method 19, Table 19-2); for MSW with an average higher heating value of 5000
BTU/lb the C02 factor is:
1820 scf/MMBTU/ 385 scf/mole x 44 lb/mole x (5000 E-6 x 2000) MMBTU/ton
= 2080 lb C02/short ton MSW, or 0.94 E-6 Tg C02/metric ton MSW
Total C02 emissions are calculated as follows:
26,037,823 metric tons x 0.94 E-6 Tg C02 Eq./metric ton
= 24.6 million metric tons, or 24.6 Tg C02 Eq.
Biogenic materials such as paper and cardboard, wood, food scraps and yard waste constitute the
majority of carbon in MSW discards. Non-biogenic wastes such as plastics, synthetic rubber and
textiles make up the remainder. This non-biogenic fraction is not known with certainty, but likely
lies within a range of 20-40% of the total MSW carbon. Using this range, the non-biogenic C02
emitted from MSW combustion is between 4.9 and 9.8 Tg C02 Eq. This value can be compared
to the total C02 from plastics, synthetic rubber and synthetic fibers in Comment Table 5. (Tires
are not burned in waste-to-energy facilities.) See Comment Table 6. This "validation check"
confirms that EPA's C02 estimate is overstated and that our revised emissions estimates are
reasonable.
Comment Table 6. 2005 WTE C02 Emissions (Tg C02Eq.)
Non-biogenic Carbon
Draft
Report
IWSA
Comments
"Validation
Check"
Range
Plastics
13.9
7.2
Synthetic Rubber in
MSW
1.9
1.0
Synthetic Fibers
2.4
0.7
Total
18.2
8.9
4.9 to 9.8
Our estimates are also supported by EPA's own report, Solid Waste Management and
Greenhouse Gases, A Life-Cycle Assessment of Emissions and Sinks (EPA 2006a). Exhibit 5-1
(page 70) of that report indicates that non-biogenic C02 emissions from "mixed MSW"
combustion are 0.10 MTCE/short ton MSW, equivalent to 0.40 Tg CO2 Eq./metric ton MSW.
For 2005, the total non-biogenic C02 emissions would be
26,037,823 metric tons x 0.40 E-6 Tg C02 Eq./metric ton
= 10.5 Tg C02 Eq.
Comparing this total value with Comment Table 5, our estimate of 11.7 Tg C02 Eq. is again
validated.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 33
Sinks: 1990-2005
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Comment 8. Based on recent test data, EPA should revise estimates to show MSW
combustion is an insignificant source of N20 emissions. (Section 3.9, page 3-51, Tables 3-43
and 3-44; Annex 3-6, page A-148)
The EPA continues to identify N20 as a characteristic emission of MSW combustion based on
test data from older, foreign sources. We are submitting a stack test report (Avogadro 2007)
containing very recent N20 emission data from a California waste-to-energy facility, a typical
U.S. plant equipped with MACT-compliant spray dryer, fabric filter, carbon injection, and
selective non-catalytic reduction air pollution control systems. The data show that no N20 was
found at a method detection limit of 1 ppmdv and an average stack oxygen concentration of
11.4% dry, or 1.46 ppmdv @ 7% 02. For MSW with a higher heating value of 5000 BTU/lb this
detection limit is equivalent to an N20 emission factor of
1.46 E-6 x 14,389 scf/MMBTU x 44 lb/mole / 385 scf/mole x 10 MMBTU/short ton MSW
= 0.024 lb/short ton MSW, or 12 g/metric ton MSW
This emission factor is much smaller than 44 g/metric ton used in EPA's calculations. Using this
emission factor, the revised 2005 annual N20 emissions from MSW combustion are less than
12 g/metric ton x 26,027,823 metric tons x 310 GWP
= 0.097 Tg C02 Eq.
These revisions reduce the 2005 estimated N20 emissions from 0.5 Tg C02Eq to <0.1 Tg
C02Eq. Unless convincingly contradicted by EPA's own data representative of MACT-
compliant U.S. waste-to-energy facilities, EPA should accept the Avogadro data and revise
Tables 3-43 and 3-44 for all reporting years accordingly.
9. EPA should review and revise its uncertainty analysis for landfills. The convoluted
methodology and absence of confirming direct measurement data suggest that the errors
associated with LFG methane estimates are greater than the uncertainty range of -39% to
+32% provided in Table 8-5. (Section 8.1, pages 8-4 and 8-5)
The methodology for calculating the amount of landfill methane emissions is represented by the
simplified expression:
CH4 Emitted = CH4 generated - CH4 recovered
Technical literature on these variables is filled with statements of uncertainty for a variety of
reasons, yet the draft report does not address these uncertainties in any detail, stating only that
there is an error range of -39% to + 32 %. Comment Table 7 provides an overview of error-based
issues that warrant EPA's review before finalizing the uncertainty analysis.
Calculation Uncertainty Problem
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 34
Sinks: 1990-2005
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Total Methane Generated
Estimate based on a theoretical model that
is never verified by actual field
measurements. Long-term emissions
including all operating phases of a landfill
must be considered.
Recovered Methane
Vendor Data
Measurements of pipeline values that are
subject to compliance monitoring would be
verifiable, but flare vendor data alone have
little value without knowing annual
capacity utilization factors for each.
EIA 1605 Database
Self-serving voluntary reports have
potential for abuse and inaccuracy, and for
double-counting in conjunction with
LMOP database
LMOP Database
A review of EPA's LMOP case studies
shows that only three sites actually have
LFG collection measurements for
comparison with theoretical predictions and
these results varied between 20 and 50%
recovery of LFG. What is the basis for an
approximate nationwide average of - 47%?
Total methane generation quantities are highly uncertain, relying on a model to predict
generation rate. The model is in turn dependent on values of two key factors derived from
laboratory experiments - the methane generation potential (Lo), and the methane generation
constant (k). In AP-42 (USEPA 1998) EPA acknowledges that "predicted methane emissions
ranged from 38 to 492% of the actual, and had a relative standard deviation of 0.85" (USEPA
1998, page 2.4-4). And this is but one of the variables associated with the estimation of landfill
methane emissions.
Another problem associated with the methodology is the reliance on EIA 1605 voluntary
greenhouse gas reporting as a source of methane control information. Aside from potential
reporting errors, there is potential for double-counting of emission reductions, as acknowledged
by EIA itself (DOE/EIA 2004). In addition, reliance on two data sources (the LMOP database
and EIA 1605 reports) to identify LFG-to-energy reduction projects compounds the double-
counting concern, attempts to identify duplicate reporting notwithstanding. A single landfill may
be known by several names including the name of the landfill, the name of the landfill operator,
the name of the LFG-to-energy project, the owner or operator of the LFG-to-energy project, etc.,
allowing reviewers to believe more projects exist than actually do.
EPA's estimating method for landfill methane emissions relies on determining the difference
between generated and collected methane because accurate direct measurement methods are not
available. EPA should promote the development and use of monitoring methods for landfill
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 35
Sinks: 1990-2005
-------
surfaces, leachate collection systems, and other methane emission points at landfills so that direct
measurement can be used as the basis of future emission estimates.
10. EPA should reconsider its landfill methane emission re-calculation. (Section 8.1,
page 8-5)
EPA provides no technical basis for the recalculation of landfill methane based on a six month
delay time aside from EPA's statement that "a more accurate integrated model was applied".
Where is the field evaluation of this statement? How does EPA simply recalculate a 4 %
reduction when the unsubstantiated error band is -39 to +32 %?
11. EPA should review and if necessary lower its flare and LFG-to-energy methane
destruction removal efficiency of 99%. (Section 8.1, page 8-4)
This 99% value used in the draft report may well be appropriate for well-maintained and
operated flares; however, this level of performance cannot be assumed as typical or average for
flares and other types of LFG combustion unless there is some form of compliance monitoring
and enforcement of this parameter. If a flare or internal combustion engine does not have an
enforceable permit condition that creates some form of limit, how can the EPA adopt a "best
case" scenario? Comment Table 8 presents data from a number of LFGTE facilities that met
permit compliance (a requirement in California), but did not achieve 99% destruction efficiency.
EPA should review these and other data and revise its default methane destruction efficiency
accordingly.
Comment Table 8. Methane Destruction Efficiency for Several LFG-to-Energ;
/ Projects
LFG-to-
Flue
Energy
Inlet
Outlet
Gas
Outlet
CH4
Facility
Emission
CH4
CH4
Flow
CH4
Destruction
Landfill A,
Engine 1
Test Date
3/23/2005
(Ib/min)
14.3
C02 (%
dry)10.8%
(ppmv)
2055
(dscfm)
6367
(Ib/min)
0.54
Efficiency
(%) 96.2%
Landfill A,
Engine 2
3/23/2005
14.4
11.1%
2965
6631
0.82
94.3%
Landfill A,
Engine 3
3/23/2005
14.7
11.2%
1991
6254
0.52
96.5%
Landfill B,
Engine 1
6/9/2005
11.4
8.2%
841
6080
0.21
98.1%
Landfill C,
Engine 1
12/29/2004
5.5
10.4%
2425
2346
0.24
95.7%
Landfill D,
Engine 1
4/8/2005
16.7
11.5%
2358
6404
0.63
96.3%
Landfill D,
Engine 2
4/8/2005
16.3
11.0%
2358
6506
0.64
96.1%
Landfill E
1/25/2005
10.6
10.6%
3790
4366
0.69
93.5%
Landfill E
4/27/2004
10.7
10.7%
2931
4382
0.53
95.0%
Landfill E
12/20/1994
12.9
13.0%
1870
4350
0.34
97.4%
References for Comments 1 to 11
Simmons, et al. (2006) "15th Nationwide Survey of Municipal Solid Waste in the United States:
The State of Garbage in America", Biocycle, April 2006.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 36
Sinks: 1990-2005
-------
Themelis, Nickolas J. and Scott Kaufman (2004) "State of Garbage in America - Data and
Methodology Assessment" Biocycle, April 2004.
Kiser, Jonathan V.L. and Maria Zannes (2004), "The 2004 IWSA Directory of Waste-to- Energy
Plants", Integrated Waste Services Association.
Department of Energy/Energy Information Administration (DOE/EIA 2007), Form EIA- 906 and
EIA-920 databases, years 2001-2005. Accessed at
http://www.eia.doe.gov/cneaf/electricitv/page/eia906 920.html (Note: The Excel file for each
reporting year can be sorted to group facilities by fuel type code such as "MSW" or "TDF" and
then summed to yield the nationwide total fuel quantities.)
USEPA (2006), "Municipal Solid Waste in the United States, 2005 Facts and Figures", Office of
Solid Waste, EPA 530-R06-011, October 2006. Accessed at
http://www.epa.gov/msw/pubs/mswchar05.pdf
Rubber Manufacturers Association (RMA 2006), "Scrap Tire Markets in the United States",
November, 2006. Accessed at
https://www.rma.org/publications/scrap tires/index.cfm?PublicationID=l 1453&CFID=1
3610617&CFTOKEN=21808729
USEPA (2006a), Solid Waste Management and Greenhouse Gases, A Life-Cycle Assessment of
Emissions and Sinks, 3rd Edition, September, 2006. Accessed at
http://epa.gov/climatechange/wycd/waste/SWMGHGreport.html
Avogadro Group (2007), "Source Test Report, 2007 Nitrous Oxide Emission Test, Solid Waste
Fuel Boiler, Unit 1, Covanta Stanislaus, Inc., Crows Landing, California", March 19, 2007.
Department of Energy/Energy Information Administration (DOE/EIA 2004), "Voluntary
Reporting of Greenhouse Gases 2004". Accessed at
http://www.eia.doe.gov/oiaf/1605/vr04data/drer.html
USEPA (1998), Compilation of Air Pollutant Emission Factors, Volume I - Stationary Point and
Area Sources, AP-42, Fifth Edition, Municipal Solid Waste Landfills, Supplement E, November
1998. Accessed at http://www.epa.gov/ttn/chief/ap42/ch02/index.html
Attachment 2
Simmons, et al. (2006) "15th Nationwide Survey of Municipal Solid Waste in the United States:
The State of Garbage in America", Biocycle, April 2006.
Attachment 3
Avogadro Group (2007), "Source Test Report, 2007 Nitrous Oxide Emission Test, Solid Waste
Fuel Boiler, Unit 1, Covanta Stanislaus, Inc., Crows Landing, California", March 19, 2007.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 37
Sinks: 1990-2005
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Comment 14
Karen Ritter—American Petroleum Institute
March 30, 2007
Review of EPA's Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005
The American Petroleum Institute (API) appreciates the opportunity to offer input to the US EPA
on the draft 2005 US inventory of greenhouse gas emissions (referred to as the EPA inventory
report). CO2
In preparing these comments, API is relying on its extensive experience in greenhouse gas
emissions estimation and reporting. This experience includes:
• Production of the Petroleum Industry Guidelines for Reporting Greenhouse Gas
Emissions (IPIECA/OGP/API, December 2003);
• Development of the API Compendium of Greenhouse Gas Emissions Estimation
Methodologies for the Oil and Gas Industry ('Road Test' version April 2001; Revised
February 2004); and
• Participation in the Expert 'Cadre' of the US Technical Advisory Group (TAG) to the
International Standards Organization (ISO).
Comments and Recommendations
• (Section 3.1. Carbon Dioxide Emissions from Fossil Fuel Combustion, p. 121) The
Recalculations Discussion indicates that EPA has revised the combustion methodology to
apply a fuel oxidation factor of 100% for all fuel types. We support this revision, which is
consistent with the recently revised 2006 IPCC Inventory Guidelines and is the preferred
approach in the API Compendium.
• (Annex 3.4 Natural Gas Systems) Table A-l 19 reports GRI/EPA ('96) Activity Factors
and Emission Factor values for the distribution stage, as stated in the text. Emissions
listed in Table A-l 19 do not correspond with the emissions in Table A-121. The
emissions in the Table A-l 19 appear to be in MEGAGRAMS and not GIGAGRAMS as
noted in the title of the table.
• (Annex 3.4 Natural Gas Systems) The Annex is the portion of the report for all the detail
behind the emission calculations. In this annex, the details behind the CH4 emission
calculations are displayed for the distribution stage as an illustration for all sectors. This
full disclosure is helpful, but EPA should disclose this same amount of background
information for all stages including: production, processing, and transportation/storage
stages.
• (Annex 3.4 Natural Gas Systems) Only the production sector has background CO2
emission data in Table A-124. More detail on the calculation of the CO2 emissions would
be appropriate in the annex for all natural gas industry sectors.
• (Annex 3.4 Natural Gas Systems Tables A-123 and A-124) Additional text in the Annex
is recommended to explain the data being displayed in these tables and how this data was
used in the calculation of CH4 and CO2 emissions.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 38
Sinks: 1990-2005
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• (Annex 3.5 Petroleum Systems) Would be helpful to provide Bcf/yr emissions data for all
years in Table A-128 in place of a repeat of Table 3-34 data.
• (3.7 Petroleum Systems and Annex 3.5 Petroleum Systems) Production categories in
report body tables do not match divisions of the sector as described in the report body or
in the Annex. Recommend using same divisions as in Annex tables.
• (3.8 Natural Gas Systems) Base year (1992) not included in emission tables.
Sincerely,
Karin Ritter
Manager
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 39
Sinks: 1990-2005
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Comment 15
Cynthia A. Finley—National Association of Clean Water Agencies
March 29, 2007
Re: NACWA Comments on Wastewater Treatment Emissions Estimates in EPA's
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005, Draft for Public Review
Dear Mr. Hockstad:
The National Association of Clean Water Agencies (NACWA) has reviewed Section 8.2,
Wastewater Treatment, of the U.S. Environmental Protection Agency's Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990 - 2005, Draft for Public Review {Draft Inventory).
NACWA represents the interests of nearly 300 publicly owned wastewater treatment agencies
nationwide. NACWA's members serve the majority of the sewered population in the U.S., and
collectively treat and reclaim more than 18 billion gallons of wastewater each day. NACWA
members are very much aware of the growing importance of global climate change and are
already engaged in efforts to reduce greenhouse gas emissions. As more state-wide and national
efforts are launched to curb levels of greenhouse gases, EPA's Inventory will certainly take on
added significance.
Our review of the Draft Inventory indicates that greenhouse gas emissions from wastewater
treatment may have been over-estimated, and our attached comments outline the factors that
appear too conservative and lead to the over-estimation. These comments are a revision of
NACWA's previously submitted comments on the Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990 - 2005, Draft for Expert Review. We appreciate EPA's response to our previous
comments, including further explanations of how emissions estimates were calculated in the
Inventory and how EPA must use the Intergovernmental Panel on Climate Change (IPCC)
protocol for the estimates in the absence of other data. NACWA appreciates the clarifications
made to the text of the Draft Inventory based on our previous comments, and we thank EPA for
its willingness to work with NACWA members to refine the greenhouse gas emissions estimates
for wastewater treatment using a data-based approach, as opposed to theoretical assumptions. We
are already investigating what data we could collect to support our recommendations for
changing the emissions estimates, and we look forward to sharing our results with you in the
future.
Thank you for the opportunity to comment on the Draft Inventory. Please contact me at 202/296-
9836 or cfinley@nacwa.org if you have any questions about our review.
Sincerely,
Cynthia A. Finley
Director, Regulatory Affairs
Attachment
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 40
Sinks: 1990-2005
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Our review of the Draft Inventory indicates that greenhouse gas emissions from wastewater
treatment may have been over-estimated, and our attached comments outline the factors that
appear too conservative and lead to the over-estimation. These comments are a revision of
NACWA's previously submitted comments on the Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990 - 2005, Draft for Expert Review. We appreciate EPA's response to our previous
comments, including further explanations of how emissions estimates were calculated in the
Inventory and how EPA must use the Intergovernmental Panel on Climate Change (IPCC)
protocol for the estimates in the absence of other data. NACWA appreciates the clarifications
made to the text of the Draft Inventory based on our previous comments, and we thank EPA for
its willingness to work with NACWA members to refine the greenhouse gas emissions estimates
for wastewater treatment using a data-based approach, as opposed to theoretical assumptions. We
are already investigating what data we could collect to support our recommendations for
changing the emissions estimates, and we look forward to sharing our results with you in the
future.
The National Association of Clean Water Agencies (NACWA) has reviewed the wastewater
treatment greenhouse gas (GHG) emission estimates contained in the Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990 - 2005, Draft for Public Review {Draft Inventory).
Overall, we are concerned that the methodology used for the emission estimates leads to an
overestimation of the contribution of wastewater treatment to total GHG emissions from all
sources. We recognize that uncertainty exists in calculations of this type and that EPA has
attempted to calculate a "mid-range" value of the GHG emissions, and determine upper and
lower bounds on the emissions estimate through an uncertainty analysis. However, we believe
that some of the factors used in the calculations are conservative, which results in elevated values
for the emissions estimates and the uncertainty bounds. NACWA's specific comments regarding
these factors are provided below.
1. As we understand the methane (CH4) emission methodology, the maximum CH4
producing capacity for domestic wastewater, termed the Bo value, of 0.6 kg CH4/kg
BOD assumes that all organic matter in wastewater treated anaerobically is converted to
CH4, whether it is biodegradable or not. This Bo value is then multiplied by a methane
correction factor (MCF) which quantifies how much of the influent organic matter is
actually converted to CH4. The MCF is 0.5 for septic systems and 0.8 for anaerobic
systems. We believe that the maximum MCF should be 2/3 or 0.67, since several well-
recognized and commonly accepted references (e.g. Metcalf & Eddy15 and Grady,
Daigger, and Lim16) indicate that no more than about two-thirds of the organic matter in
domestic wastewater is biodegradable. The MCF accounts for the portion of the organic
matter that is stabilized anaerobically (versus aerobically) and also for the portion that is
incorporated into sludge. The fact that all wastewater treatment facilities produce sludge
reinforces the fact that an MCF of 0.8 is overly conservative. Thus, it appears that the
maximum CH4 producing potential was coupled with the maximum potential conversion
15 Tchobanoglous, G., F.L. Burton, and H.D. Stensel, Wastewater Engineering: Treatment and Reuse, Metcalf &
Eddy, Inc. 4th Edition, McGraw-Hill, New York, 2003.
16 Grady, C. P. L., Jr., G. T. Daigger, and H. C. Lim, Biological Wastewater Treatment, 2nd Edition, Marcel Dekker, NY,
1999.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 41
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to CH4, resulting not in a "mid-range" estimate but rather a "worst case" estimate. This
methodology therefore appears to result in an overestimation of CH4 emissions from
domestic wastewater treatment.
2. The Draft Inventory separates central wastewater treatment systems into two categories:
aerobic and anaerobic. No direct CH4 emissions are assumed for the aerobic systems, but
an MCF of 0.8 is assumed for the anaerobic systems. As explained in Comment 1 above,
we suggest that the MCF should be no more than 0.67 if the system is fully anaerobic.
However, exclusive anaerobic treatment of domestic wastewater is not practiced in the
U.S. Instead, the general practice is to use facultative lagoons which incorporate a
combination of aerobic and anaerobic processes or natural treatment systems such as
wetlands that use largely aerobic treatment mechanisms (see Metcalf & Eddy). Given the
fact that these systems incorporate both aerobic and anaerobic treatment mechanisms, we
suggest that a MCF of less than 0.67 (our recommended maximum value for anaerobic
systems from Comment 1) is appropriate for these systems. In the Planned Improvements
Discussion section of the Draft Inventory, EPA indicates their intention to investigate this
further and potentially "differentiate between anaerobic systems to allow for the use of
different MCFs for different types of anaerobic treatment systems." We support this
planned improvement.
3. Our analysis indicates that the total nitrogen load to wastewater treatment plants is
systematically overestimated in the Draft Inventory, resulting in an overestimation of
N20 emissions from wastewater treatment. The Draft Inventory estimates nitrogen
discharges to wastewater based on reported annual protein consumption, which is the
methodology used in the Intergovernmental Panel on Climate Change (IPCC) protocol
document17 (IPCC Guidelines). Expressed as nitrogen (N), the estimate for domestic
sources is developed as follows: 42.1 kg protein/person/year x 0.16 kg N/kg protein x 1.4
Factor for Non-Consumption = 9.43 kg N/person/year This is further increased by a
factor of 1.25 to account for industrial discharges, resulting in a total value of 1.25 x 9.43
or 11.79 kg N/person/year This value differs significantly from per capita wastewater
discharge rates presented in standard references such as Metcalf & Eddy. Metcalf & Eddy
report per capita nitrogen discharge rates to wastewater of 0.015 kg N/person/day.
Converting this to a yearly value gives: 0.015 kg N/person/day x 365 days/year = 5.48 kg
N/person/year This is less than half the value used in the Draft Inventory calculation. The
values presented in standard industry references such as Metcalf & Eddy are supported
by a wealth of data and have been widely confirmed in U.S. practice. We recommend that
the IPCC protocol be replaced by a nitrogen discharge rate based on data collected from
wastewater treatment plants in the U.S. This type of data, which was used in Metcalf &
Eddy, includes all domestic sources of nitrogen, including meal production and
consumption, the use of other nitrogen containing compounds, and both residential and
commercial sources. The extent that this data includes incidental industrial discharges is
unknown. In our judgment, the "base-line" or "mid-range" estimate of per capita nitrogen
discharge should use a standard value near Metcalf & Eddy's 5.48 kgN/person/year. The
17 IPCC, 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National 18 Greenhouse
Gas Inventories Programme, Eggleston H.S., Buenida L., Miwa K., Ngara T., and Tanabe K. (eds.) 19 Published:
IGES, Japan, 2006.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 42
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uncertainty analysis should then consider the possibility of industrial discharges not
incorporated into the standard per capita values, multiplying by the 1.25 factor currently
used in the Draft Inventory. We recognize that EPA will need data to verify this
recommended change, and NACWA is willing to work with EPA to obtain this data from
wastewater treatment plants.
4. The Draft Inventory utilizes default IPCC emission factors to calculate N20 emission
rates from wastewater treatment. These emission factors are very uncertain, though, as
explained in the IPCC Guidelines and noted in the Planned Improvements Discussion
section of the Draft Inventory. For example, the default emission factor for nitrogen
discharged in plant effluents is 0.005 kg N20-N/kg sewage-N produced, but the range of
possible values extends over many orders of magnitude, from 0.0005 to 0.025 or 0.25. In
the IPCC Guidelines, the upper bound is shown as 0.025 in Table 11.3 and as 0.25 in
Section 6.3.1.2. The upper range used by EPA should be clarified. Also, the results of the
uncertainty analysis in the Draft Inventory indicate a 95 percent confidence interval of
only 38 percent below to 47 percent above the emission estimate, which does not seem to
reflect the high degree of uncertainty in the emission factor. Based on this large
uncertainty and the seemingly arbitrary choice of the 0.005 factor value in the IPCC
Guidelines, NACWA believes that more work is needed to refine the emission factors
and determine a more accurate N20 emission estimate for wastewater treatment.
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 43
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Comment 16
Rhea Hale—American Forest and Paper Association
March 29, 2007
RE: Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and
Sinks: 1990-2005
The American Forest & Paper Association (AF&PA) appreciates the opportunity to comment on
EPA's Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005. AF&PA is the
national trade association of the forest, paper, and wood products industry. AF&PA represents
more than 200 companies and related associations that engage in or represent the manufacture of
pulp, paper, paperboard, and wood products.
In the draft inventory, the "Harvested Wood Carbon" discussion on page 10 of Chapter 7, Land
Use, Land-Use Change and Forestry indicates that the methodology for calculating carbon
sequestration in products has changed from the methodology used in previous years.
The new mathematical relationship for describing the time in use of harvested wood products,
the first order decay curve, does not adequately describe the fate of certain paper products that
may have short half-lives but where a significant fraction of the material remains in use for long
times (e.g. paper used in gypsum board and newsprint insulation). The time-in-use curves should
reflect this long-term storage. The curve previously used to develop the estimates, the Row and
Phelps decay curve, was more appropriate for these materials.
Thank you for your consideration and please do not hesitate to contact me should you have any
questions regarding these comments.
Sincerely,
Rhea Hale
Director, Climate and Air Programs
American Forest & Paper Association
1111 Nineteenth Street, NW, Suite 800
Washington, D.C. 20036
202-463-2709
Public Review Comments on the Draft Inventory of U.S. Greenhouse Gas Emissions and 44
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