been estimated to be between 60 and 100 Tg/year,”
accounting for about 15 percent of total global
CH, emissions from all sources.

Previous estimates of global CH, emissions from
ruminant digestive processes have several notable
deficiencies, including the following:

-- Previous estimates failed to reflect important
differences in CH, emissions associated with
various stages of animal growth and management.
For example, in the U.S. about 25 percent of beef
cattle are in fact calves with CH, emissions rates
significantly lower than emissions associated with
adult beef cows.

-- For cattle on poor quality forages, previous CH4
emissions estimates appear to underestimate feed
intakes and overestimate CH, yield per amount of
feed intake. The net effect of these two factors
is that overall emissions associated with these
populations of animals appear to be
underestimated, possibly by large amounts.

-- Previous estimates have neglected potential
emissions from animal wastes.

-- Previous estimates failed to consider differences
in animal sizes and differences in the feed base
of the animals.

-- Estimates of global animal populations need to be
refined.

While previous estimates of CH, emissions from ruminant
digestive processes are deficient in various respects,
the overall magnitude of the estimates is reasonable.
Key analyses should be undertaken to improve the
emissions estimates, especially for areas in which
interventions are most likely to be cost effective.
The major animal management systems should be
enumerated, and the analyses should focus on the key
systems that contribute most to global emissions, and
that have the potential to be controlled.

Animal wastes (including the wastes from non-ruminants
such as poultry and swine) are a potentially large
source of methane emissions. Under anaerobic waste
management systems, uncontrolled CH, emissions from

15

11 = 10" grams = 10° kilograms = 10° metric tons.

55



EXHIBIT D-1

Paddy Rice Requirements at 1985, 2020, 2100

(million tons)

scenario 1985 2020 2100
I. Status Quo

a. Top 20 Rice Producers 400 620 790
b. Rest of World 40 _60 _80
c. Total 440 680 870

II. Hunger Reduction by 15 percent
a. Top 20 Rice Producers 450 710 910
b. Rest of World 50 wat) 90
500 780 1,000

Source:

IRRI, 1988.



° The lifetime of methane is approximately 10 years and
that of carbon dioxide effectively 230 years (Lashof
and Ahuja, 1990).

. In the atmosphere methane participates in chemical
reactions that lead to the formation of tropospheric
ozone, itself a greenhouse gas. This tropospheric
ozone formation amplifies the methane's IR radiation
absorption direct effects by about 70 percent (Lashof,
1989).

Thus, gram for gram methane in the atmosphere is about 120 more
times more potent than a gram of carbon dioxide in the atmosphere
in terms of its immediate ability to absorb IR radiation. In
addition, the GWP must account for the natural conversion of
methane into water and carbon dioxide by hydroxyl ions which
occurs over time. Since this scavenging is limited by the
concentration of hydroxyl ions, an increase in methane emissions
tends to reduce the rate of the destruction of methane with a 10
percent increase in methane emissions increasing the
concentration of methane by an additional 15 percent (Thompson
and Cicerone, 1986).

Exhibit 8 shows the GWPs for methane as a function of the
time horizon over which the warming is compared. Since methane
is a relatively short-lived gas, the large ratio of 120 to 1 is
reduced over longer time periods as methane is destroyed and
carbon dioxide stays in the atmosphere. The warming from methane
is realized in the first few decades after the emission while the
warming from carbon dioxide is realized gradually over centuries.
Consequently, the GWP of methane decreases with longer time
horizons.

Working Group 1 of the IPCC has also estimated GWPs of trace
gases. With a somewhat different method for assessing the
indirect effects of methane, their estimates of GWPs are somewhat
different, although not much smaller than those presented at the
EIS workshop. These GWPs are also shown in Exhibit 8.

In terms of the radiative forcing prevented over the next 50
years, a reduction in methane emissions of 40 Tg is equivalent to
preventing about 1,400 Tg of carbon dioxide emissions, which is
about 6 percent of the total global carbon dioxide emissions from
human activities.

One implication of this analysis is that near-term methane
emissions reductions will be more effective than similar carbon
dioxide emissions reduction in slowing actual warming experienced
in the next 30 to 100 years. Because of their differing relative
impacts, actions to reduce methane and carbon dioxide emissions
actually serve two different, important and complementary goals

21



Doris Ann Cash

Mine Safety and Health Admin
Dept of Labor

Technical Support

4015 Wilson Blvd. Rm 937
Arlington, VA 22202

Tel: 703-235-1590
FTS8: 235-1590

Jeff Chandler

Jeff Chandler & Associates
PO Box 896

Elk Grove, CA 96759

Tel: 916-458-0126
Fax: 916-689-1968

Chai Wenling

Planning Dept., Ministry of
Energy

137 Fuyou street

Beijing 100031

China

Tels 054131-470 or -430
Fax: 001 6077
Telex: 222866 MEDIC CH

8. Chattopadhya

The World Bank

Room # F 10.019

1818 H Street, NW
Washington, DC 20433

Tel: 202-477-6644

Jason Ching

USEPA

AREAZ/ASMD (MD 80)
Reasearch Triangle Park, NC
27711

Tel: 919-541-4801
Fax: 919-541-1379

chris Collins

Eden Resources - Environmental
Consultants

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Wellington, New Zealand

Tel: 846-583
Fax: 6846-583

R. Mike Cowgill

Pacific Gas & Electric Co.
R&D Department

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San Ramon, CA 94583

Tel: 415-866-5727 or
415-866-8107
Pax: 415-866-5318

Dr. David P. Creedy

British Coal Corporation
Headquarters Technical Dept.
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Burton-on-Trent; Staffs; DE15
o2D

England

Tel: (0)283-550500 ext. 31659
Telex: 341741 CBTD G

Andras Csethe

Mecseki Szenbanyak Pecs/Hung
PO Box 109

Pecs/Hungary, Sallai U. 48

Tel: 00-36-72-11523
Telex: 00-36~72-012242

Ken Darrow

Energy International, Inc.

127 Bellevue Way SE, Suite 200
Bellevue, WA 98004

Tel: 206-453-9595

Pax: 206-455-0981
Telex: 296751

Page E-12



Bryce Payne

USDA-Agriculture Research Service
Rodale Research Center

RD-1, Box 323

Kutztown, PA 19530

USA.

Phone: 215-683-6383

Paavo Pelkonen
University of Joensuu
Faculty of Forestry

Box 111

SF-80110 Joensuu
FINLAND

Phone: 358-73-151-3629
Fax 358-73-151-3590

Joao Luiz Pereira-Pinto
Brazilian Embassy

3006 Massachusetts Ave, NW
Washington, D.C. 20008
USA.

Phone: 202-745-2750

Fax = 202-745-2728

Don Plucknett

CGIAR - World Bank
Room N5053

1818 H Street, NW
Washington, D.C. 20433
USA.

Phone: 202-334-8033
Fax: 202-334-8750

Wilfted M. Post

Oak Ridge National Laboratory
P.O. Box 2008, Bldg. 1000

Oak Ridge, TN 37831-6335
USA.

Phone: 615-574-0390

L. Benzing-Purdie

Agriculture Canada - Research Branch
Sir John Carling Building

Ottawa, KIA 0CS

CANADA

John Ragland

AID/BIFAD

5314 A State Dept. Building
Washington, D.C. 20523
USA.

Phone: 202-647-6987

Peter Ramshaw

World Wildlife Fund for Nature
Conservation and Development Officer
Panda House, Weyside Park
Catteshell Lane, Godalming

Surrey GU7 1XR

UNITED KINGDOM

Phone: 44-4-83-426444

Fax = 44-4-83-426409

Telex: 859602

Richard Rapoport

Congress of The United States
Office of Technology Assessment
Washington, D.C. 20510-8025
USA.

Phone: 202-228-6863

Fax —- 202-228-6098

Stephen L. Rawlins
USDA/ARS

National Program Staff
Barc-W Building 005
Beltsville, MD 20705
USA.

Phone: 301-344-4034
Fax 301-344-3191

KR. Reddy

Soil Science Department
University of Florida
Gainesville, FL 32611
USA.

John Reilly
Economic Research Services
US. Department of Agriculture
Room 524

1301 New York Avenue, N.W.
Washington, D.C. 20005-4788
Phone: 202-786-1448

Fax 202-786-1477

Page E-7





c.4 References

Bingemer, H.G. and P.J. Crutzen (1987), "The Production of
Methane from Solid Wastes," Journal of Geophysical Research, Vol.

92, No. D2, pp. 2181-2187, February 20, 1987.

Casada, M.E. and L.M. Safley, Jr. (1990), "Global Methane
Emissions from Livestock and Poultry Manure," presented at the
International Workshop on Methane Emissions, April 9-13, 1990,
Washington, D.C., sponsored by the Environment Agency of Japan
and the U.S. Environmental Protection Agency.

Chandler, et. al. (1979), Second Symp. Biotech. Energy Prod.
Conversion.

Chian, Edward S.K. and Foppe B. DeWalle (1979), "Effect of
Moisture Regimes and Temperature on MSW Stabilization," in
Municipal Solid Waste: Land Disposal, Proceedings of the Fifth
Annual Research Symposium, U.S. Environmental Protection Agency,
EPA-600-9-79-023a, August 1979.

Gibbs, Michael J., Lisa Lewis and John S. Hoffman (1989),
Reducing Methane Emissions from Livestock: Opportunities and
Issues, U.S. Environmental Protection Agency: Washington D.C.,
EPA 400/1-89/002, August 1989.

Gunnerson, Charles G. and David C. Stuckey (1986), Integrated
Resource Recovery: Anaerobic Digestion Principles and Practices
for Biogas Systems, World Bank Technical Paper Number 49,
Washington, D.C.

Ham, Robert K., and Morton A. Barlaz (1987), "Measurement and
Prediction of Landfill Gas Quality and Quantity," Presented at
ISWA Symposium "Process, Technology, and Environmental Impact of
Sanitary Landfill," Cagliari, Sardinia, Italy, October 20-23,
1987.

Hashimoto, A.G., V.H. Varel and ¥.R. Chen (1981), "Ultimate
Methane Yield from Beef Cattle Manure; Effect of Temperature,
Ration Constituents, Antibiotics and Manure Age," Agricultural
Wastes, Vol. 3, 1981, pp. 241-256.

Jewell, et. al. Fuel Gas Production from Biomass, D.L. Wise
(ed.), CRC Press, Boca Raton, Vol. 1, p. 215.

Mancinelli, Rocco L. and Christopher P. McKay (1987), "Methane-
Oxidizing Bacteria in Sanitary Landfills," in A.A. Antonopoulos
(ed.) Biotechnological Advances in Processing Municipal Wastes

Page C-17



Leng, R.A. (1990), Improving Ruminant Production and Reducing

Metha: sions from Ruminants b’ trategic ementation,
Draft report submitted to the U.S. EPA, Washington D.c.

Marland, G., and R.M. Rotty (1984), "Carbon Dioxide Emissions
from Fossil Fuels: A Procedure for Estimation and Results for
1950-1982," Tellus, vol. 36B, p. 232-261.

Rinsland, C.P., J.S. Levine and T. Miles (1985), "Concentration
of Methane in the Troposphere Deduced from 1951 Infrared Solar
Spectra," Nature, vol. 318, p.245-249.

Steele, L.P., P.J. Fraser, R.A. Rasmussen, M.A.K. Khalil, T.J.
Conway, A.J. Crawford, R.H. Gammon, K.A. Masarie, and K.W.
Thoning (1987), "The Global Distribution of Methane in the

Troposphere," Journal of Atmospheric Chemistry, Vol. 5,
p. 125-171.

Thompson, A.M. and R.J. Cicerone (1986), "Possible Perturbations

to Atmospheric CO, CH4, and OH," Journal of Geo sica 2: '
vol. 91. no. D10, p. 10853-10864.

WMO (1990), Scientific Assessment of Stratospheric Ozone: 1989,

World Meteorological Organization, Global Ozone Research and
Monitoring Project-Report No. 20, Geneva, Switzerland.

64



WORKSHOP ATTENDEES

WORKSHOP OF THE ENERGY AND INDUSTRY SUBGOUP (EIS)

Louis J. Aboud

american Gas Association
1515 Wilson Blvd.
Arlington, VA 22209

703-841-8652
703-841-8406

Tel:
Fax:

Dennis B. Amanda
Alphatania Group
st. Gennys

Pines Rd, Fleet
Hants Gui3 8sNL
England

Tel:
Fax:

0252-615266
0252-628378

Dilip Ahuja

The Bruce Co.
PM-221, EPA
Washington, DC 20460

Tel:
Fax:
Telex:

202-382-6935
202-479-1009
892758 EPA WSK

Riva Angelo
Snam 8.P.A
RED Division
PO Box 12060
20120 Milano
Italy

Tel:
Fax:
Telex:

(02) -5207934
(02) -$2024435
310246 EMI SMAM

David W. Barns

Senior Research Engineer
Pacific Northwest Laboratories
370 L’Enfant Promenadae, SW
Suite 900

Washington, DC 20024-2115

202-646-5223
202-646-5233

Tel:
Pax:

801 Battino

c/o BHP Engineering
9 Dalman Place
Sylvania Nsw 2224

Australia
Tel: 02-5228448
Pax: (Aust) 042-280893

Lee Beck

Global Warming Control Branch
Siobal Emissions and Control
Div.

U.8. Environmental Protection
Agency

MD-63

Research Triangle Park, NC
27721

Tel: 919~541-0617

Robert Berman

U.8. Department of Interior
Office of Policy Analysis - us
4412

18th and C Streets, NW
Washington, DC 20240

Tel: 202-208-3751
Fax: 202-208-4867
A. D. Bhide

Scientist & Head, Solid Wastes
Div.

National Environmental Eng.
Research Institute, Nemrumarg,
Nagpur - 440020

India

Tel:
Pax:
Telex:

26252-526071
23893
0712-233

Page £-10



Teragrams Methane/Vear Teragrams Methane/Year

Teragrams Methane/Year

60

40

30

20

EXHIBIT A-2

METHANE EMISSIONS FROM ENERGY RELATED SOURCES
THROUGH 2025

omer Deveicnns MIE THANE EMISSIONS
crmeceass FROM

TT TTT T

e: “Wits
ep Sd uss a europe
Neen eateteaatatatatts NATURAL GAS

RRR ED PRODUCTION

United States

“aes 1990 2000 2010 2020 2028
Year
140
120 Other Developing
Asascasn METHANE EMISSIONS
100

40

30

20

Q
2965 1990

China & CP Asia FROM
COAL PRODUCTION

on a a

USSR GE. Europe

oon
LEK KRRE KER KER ORG
LLLELELLE LESS

R-OECD
United States

2985 1990 2000 2010 2020 2025

Year

otrer cevetcning METHANE EMISSIONS
S HSE Asia FROM

China & CP Asia

RRA REEERGRKGG #8 £27 LANDFILLS

ECO

TTT

2020 2025
Year

Page A-9



evidence to fall between 440 and 640 Tg per year. The factors
that constrain this range are described in Cicerone and Oremland
(1988).

Emissions from these activities are expected to increase
over the next decade, and to lead to increasing atmospheric
concentrations of methane. Business-as-Usual Scenarios for
methane emissions and concentrations are shown in Exhibit 4 and
Exhibit 5. By 2100, methane concentrations are about 4000 ppbv,
or more than doubled from current levels.

Methane's increasing concentration in the atmosphere is
important from the perspective of global climate change because
methane is very effective at absorbing infrared (IR) radiation.
A gram of methane added to today's atmosphere will initially
absorb about 70 times as much IR radiation as would a gram of
carbon dioxide (CO,). Unlike carbon dioxide, however, methane
has a relatively short atmospheric lifetime, on the order of 10
years, and consequently, the impact of a given amount of methane
emissions is relatively short-lived.

Methane's strong IR radiation absorbing characteristic,
combined with its relatively short atmospheric lifetime, make it
very different from the other major radiatively-important trace
gases. In addition, the characteristics of the sources that emit
methane are very different from the sources that emit other
greenhouse gases such as carbon dioxide and CFCs
(chlorofluorocarbons). These differences indicate that methane
control may be a good opportunity for achieving near-term
benefits in terms of slowing the rate of global warming. The
opportunity that methane presents is explored further below,
after additional documentation is presented on rising methane
concentrations and on the extent of reductions required for
stabilization of methane concentrations in the atmosphere.

2.1 Methane Concentrations Are Increasing

It is well documented that global average methane
atmospheric concentrations are increasing. Measurements have
been performed at six primary sites between 1979 and the present,
including frequent and regular measurements at Cape Meares,
Oregon. Methane measurements have also been performed by the
NOAA/GMCC global distributed monitoring network since 1983.
Methane concentrations have increased at every site analyzed
consistent with the measurements at Cape Meares (WMO, 1986) .°

6 published estimates of the recent increases in

atmospheric methane levels include: Blake and Rowland (1986);
Blake and Rowland (1988); Steele et al. (1987); Ehhalt et al.
(continued...)
11



and following the release of organic matter, in the form of root
exudates and root litter, at the heading and flowering stages of
the rice plants.

CH, Oxidation. The action of CH, oxidizing bacteria
(methanotrophs) is important in limiting the flux of CH, to the
atmosphere. CH, can be oxidized by both aerobic and anaerobic
bacteria; the processes involved in aerobic oxidization are
better understood, and these bacteria can be found in rice
paddies at the narrow oxidized floodwater-soil interface. Seiler
and Conrad (1981) estimate a global CH, consumption rate by
methanotrophs of 31 + 16 Tg/year, and Holzapfel-Pschorn et al.
(1986) report that 67 percent of the CH, produced during a rice
growing season was oxidized and only 23° percent escaped to the
atmosphere.

Plants and CH, Transport. The rice plants themselves are
the major conduits for CH, transport to the atmosphere.
Holzpfel-Pschorn et al. (1986) report that emissions via the
plant constitute more than 90 percent of the total emissions (the
remaining emissions escaping by ebullition and diffusion through
the water column), and note that the flux rate is controlled by
the rate of CH, production in the soil and is not curtailed by
limitations of the diffusion processes from the soil into the
root system or through the aerenchyma of the plant. The
emissions from fields without rice plants are reported to be
about 50 percent of those with plants and the emissions are
almost exclusively due to ebullition (Schutz et al. 1989).

Water Depth. The depth of the paddy soil water may also
affect the CH, flux; Sebacher et al. (1986) report that increases
in floodwater depths up to 10 cm cause increased CH, emissions
but further increases decrease the emissions.

Rice Production System. Flooded rice paddies produce CH, i
dry upland rice does not. About 87 percent of the rice cropping

area worldwide consists of various forms of wetland rice (e.g.,
irrigated, rainfed, deep-water), (Dalyrymple 1986). The
floodwater depth and the length of the flooding period are both
believed to affect CH, emissions (Sebacher et al. 1986).

Application of Organic Matter. The nature, volume and mode

of application of organic matter to rice paddy soil is known to
affect CH, production; studies indicate that organic matter
application enhances emissions (Delwiche 1988, Minami 1989, and
Washida 1989). In addition, more information is needed on
emissions patterns in Asia where organic fertilizer (as opposed
to mineral fertilizer) is predominantly used in rice cultivation;
information is also needed on the effect of such practices as the
incorporation of crop residues (e.g., rice-straw) into the paddy
soil.

Page 0-8



EXHIBIT D-6

GLOBAL METHANE EMISSIONS FROM RUMINANT ANIMALS

Methane Emission

per animal Total annual
Animal (kg/yr) emissions

(Tg) *
Cattle in developed
countries 55 31.5
Cattle in developing
countries 35 22.8
Sheep in developed
countries 8 3.2
Sheep in developing
countries 5 3.7
Buffalo 50 6.2
Goats 5 2.4
Camels 58 1.0
TOTAL 71.0

* 1ttg= 10 grams

Source: Crutzen, P.J., I. Aselmann, and W. Seiler, "Methane
Production by Domestic Animals, Wild Ruminants, Other Herbivorous
Fauna, and Humans," Tellus, 38B, 1986, pp. 271-284.

Page 0-14



EXHIBIT A-1

SOURCES OF METHANE EMISSIONS
10° Grams per Year

Annual
Emissions Range Comments. Source
Animals 80 65 - 100 Livestock in developed Cicerone and
and developing Oremtand
countries.
Animal Wastes 35 NR? Anaerobic decomposition pce
of organic wastes.
Wastewater NR 20 - 25 Anaerobic decomposition IPCC
of organic matter in the
waste water stream
Rice Paddies 110 60 - 170 Principally in Cicerone and
developing countries. Oremland
Coal Mining NR 30 - 50 Surface and (mostly) IPCC
sub-surface mining.
Oil/Gas Systems 45 25 - 50 Production, transmission Cicerone and
and distribution. Oremland
Landfills NR 25 - 40 Decay of organic wastes. 1PCC
Biomass Burning 55 50 - 100 Forest clearing and Cicerone and
waste burning. Oremt and
Natural Wetlands 5 100 - 200 Tundra, bogs, swamps, Cicerone and
alluvial formations. Oremland
Termites 40 10 - 100 Bacteria within termites Cicerone and
produce CH, as part of Oremt and
the termite's digestive
process.
Oceans and 15 6-45 Cicerone and
Freshwaters Oremland
Hydrates 5? 0 - 100 Potentially important Cicerone and
future source. Oremland
Total Emissions” 540 440 - 640 Well constrained. Cicerone and
Oremland

Sources: Cicerone and Oremland (1988), "Biogeochemical Aspects of Atmospheric Methane," Global
Biogeochemical Cycles, December 1988. IPCC, December 1989 and April 1990 IPCC workshops on methane
emissions.

@ WR = not reported at the IPCC workshop

5 Total annual emissions of 540 Tg per year +100 Tg is well constrained based on observational
data. The point estimates of the individual source estimates presented here do not sum to 540 Tg.

Page A-4



100 Tg/yr (67 to 170 Tg/yr). This level of emissions reduction
is clearly sufficient to stabilize methane emissions.

Over the next 10 years about one-third of these technically-
feasible reductions need to be achieved in order to stabilize
atmospheric methane concentrations. The extent to which
emissions will actually be reduced from each source will depend
on the level of resources committed to undertaking the steps
necessary to reduce emissions. At this time, the estimate of
actual emissions reductions that can be achieved in the near term
is quite subjective, and more research is needed.

Exhibit 9 shows one set of estimates of how adequate
emissions reductions could be achieved across the various
emissions sources in order to stabilize concentrations. Although
the precise estimates of achievable reductions are uncertain, it
is expected that the near-term emissions reductions identified in
the exhibit can likely be achieved because they depend on
existing technologies that in many cases are cost effective in
their own right or provide other important benefits.

For example, the U.S. is in the process of proposing rules
to reduce emissions of toxic air contaminants from landfills. As
a consequence, methane emissions from landfills will be reduced
by about 40 to 50 percent in the following 10 years. Much of
this methane can additionally be recovered and used to displace
carbon intensive fuels. Similarly, techniques for pre-mining
coalbed methane drainage and gob gas recovery and utilization
have now been demonstrated. With some effort, these techniques
may become economic in their own right in many locations.
Coalbed methane resources may become an important source of gas
supplies in some parts of the world.

Similarly, programs to increase animal productivity via
strategic supplementation have been initiated in some areas of
the world; reducing methane emissions is a side benefit (Leng,
1990). Such programs could be encouraged more broadly.
Additionally, proven technologies, such as the administration of
bovine somatotropin (bST) to increase milk production, can also
reduce methane emissions over the next 10 years.

While significant research and analysis remain to be done,
the results of the IPCC Workshops indicate that practical
techniques exist to reduce methane emissions by an amount that
can lead to the stabilization of methane concentrations.
Additionally, implementing the available opportunities for
reducing methane will help restrain growth in methane emissions
in the long-term. For example, methane emissions from landfills
and coal mines will not increase as much as currently anticipated
in the RCW and SCW scenarios if methane recovery and utilization
become standard practice at most of these facilities.
Consequently, restraining the long-term growth in methane

28



APPENDIX C

WASTE MANAGEMENT

c.1i Landfills
Emissions

Olid waste landfills are estimated to account for 30 to
70 Tg of annual global methane (CH,) emissions, which is roughly
7 percent of all CH, emissions and about 14 percent of the
anthropogenic emissions (Bingemer and Crutzen, 1987).
Exhibit C-1 shows the assumptions used to generate this global
estimate. Exhibit C-1 also shows estimates of CH, emissions from
different parts of the world and from different types of waste.

By far the largest contribution of CH, from landfills is
from developed countries. CH, emissions from landfills can be
expected to increase as world population grows, if waste disposal
practices do not change. In addition, a major shift in the
largest contributors can be expected as waste dumping rates in
the developed countries continue to slow down and as population
growth and increasing urbanization in the developing countries
lead to more waste dumping.

Discussions at the IPCC Workshop included estimates of
emissions from individual countries and regions, including:

. Canada: 1 Tg per year;

. Japan: 0.17 Tg per year;

. Oceania: 1.25 Tg;

. United States: 8 to 18 Tg per year;

. USSR and eastern Europe: 5 to 8 Tg per year; and
. Developing Countries: 4 to 7 Tg per year.

The range of global emissions estimates discussed at the workshop
was 25 to 40 Tg per year. This range is at the low end of the
range estimated by Bingemer and Crutzen (1987).

' 4 Tg = 1 teragram = 10% grams = 10° kilograms = 1 million

metric tons.



. how representative the systems are upon which
preliminary estimates are based.

Additional data are required to improve existing
estimates. These future estimates of methane emissions
must differentiate among the sources of emissions,
separating out:

. oil production;

. gas production;

. gas transmission;

. gas distribution; and
. gas consumption.

These estimates must also differentiate emissions on
the basis of age:

. new systems versus old systems.

A combination of actual atmospheric measurements and
accounting and engineering studies are needed to
validate the improved estimates. These studies need to
be scientifically credible, independently performed or
independently verified, and subject to public
examination.

Leak Detection and Mitigation: Potential for Emission
Reduction

3.1

Gas transmission and distribution companies employ a
variety of leak detection and mitigation technologies.
These technologies are employed primarily to maintain
the safety of natural gas use and to meet required
regulations. The precision and cost of techniques
varies.

With the aid of state-of-the-art equipment and rigorous
surveillance programs, it is technically possible to
detect and reduce methane emissions from transmission
and distribution systems, from unintentional and
intentional leakage. There may be opportunities for
more widespread use of the techniques with the greatest
precision and accuracy. For example, pneumatically-
driven devices could be replaced by electrical (non-
pneumatic) devices. Similarly, leaks that do not pose
a safety risk could be repaired based on the
environmental benefit.

35



Hideo Taki

Osaka Gas Co., Ltd
Corporate Planning Dept.
4-1-2, Hiranomachi, Chuo-ku
Osaka 541

Japan

Tel: 81-6-231-1748
Fax: 81-6-222-5831

Tang Hui Min

Chief Engineer

Jianshe Road, Tangshan,
Hebei Province

People’s Republic, China

Tel: Tangshan 21458
Telex: 27207 CNTSKLY

Christian Tauszsiede
CERCHAR

BP2

60550 Verneuil en Halatee
France

Tel: 33 44 55 66 77
Pax: 33 44 55 66 99
Telex: 140 094 F

Pramod C. Thakur, Ph.D.
Consolidation Coal Co.
Rt 1, Box 119
Morgantown, WV 26505

Tel: 304-983-3207
Fax: 304-983-3209

Susan Thorneloe

US EPA

MD-62

Research Triangle Park, NC
277121

Tel: 919-541-2709
Fax: 919-541-2382

Basat H. Tilkicioglu
Pipeline Systems Inc.
460 N. Wiget Lane
Walnut Creek, CA 94598

Tel: 415-939-4420
Fax: 415-937-8875
Telex: 910-481-3601

Kyoji Tomita

Tokyo Gas Co., Ltd.
1-5-20 Kaigan
Minato-ku, Tokyo 105
Japan

Tel: 011-81-3-433-2111
Fax: 011-81-3-437-9190
Telex: J-33663

Lori Traweek

American Gas Association
1515 Wilson Blvd.
Arlington, VA 22209

Tel: 703-841-8453
Fax: 703-841-8406
Telex: 710-955-9848

Michael A. Trevits

U.S. Bureau of Mines
Pittsburgh Research Center
PO Box 18070

Pittsburgh, PA 15236

Tel: 412-892-6556
Pax: 412-892-6614

W. Gregory Vogt

8CS Engineers

11260 Roger Bacon Drive
Reston, Virginia 22090

Tel: 703-471-6150
Pax: 703-471-6676

Page E-22



) uctiv iency t et
e Improvements in reproductive efficiency
will reduce CH, emissions by reducing the size of the
brood herd needed to sustain a given level of
production. Opportunities to accelerate promising
developments in this area should be explored.

Microbiological Approaches.
-- rove microbia i
iber di t. t) m i
synthesis. CH, emissions may be reduced by

balancing the rumen processes so that maximum
efficiency is achieved. Microbiological
approaches for promoting and achieving this
balance should be explored. Analyses of feeds,
feed combinations, feed treatments, bio-
engineering opportunities and other techniques
should be explored.

-- Reduce CH, production by manipulating VFA

ns_an id tl
methanogens. Techniques for promoting propionate
production (a hydrogen sink) should be explored.
Additionally, inhibiting methanogens may provide
an opportunity for altering the fate of H, in the
rumen such that less CH, is produced.

Modifications to animal waste management practices. It
is anticipated that anaerobic animal waste management
practices produce significant CH, emissions.

Reductions in these emissions are possible.

-- Opportunities for modifying waste management
practices in a manner that is consistent with
other environmental objectives (such as protecting
groundwater quality) should be identified.

-- Opportunities for recovering CH, from animal
wastes should be explored on various levels,
including: (1) integrated resource recovery
systems that produce a variety of useful products;
(2) anaerobic digesters that produce gas that can
be used as a commercial energy source or flared;
anda (3) small scale projects applicable for small
farmers.

-- The costs of the alternative waste management
systems must be estimated and balanced against the
value of products produced. Indications are that

60



Lindsay Mitchell

Ministry of Agriculture, Fisheries, and Food
Environmental Protection Division, Rm. 146
Nobel House, 17 Smith Square

London, SWIP JR

UNITED KINGDOM

Phone: 44-1-238-5669

Fax: — 44-1-238-6700

Richard Morgenstern

US. Environmental Protection Agency
PM-221

401 M Street, SW

Washington, D.C. 20460

USA.

Phone: 202-382-4034

Mark A. Moser
RCM Digesters

P.O. Box 4715
Berkeley, CA 94704
USA.

Phone: 415-658-4466
Fax 415-658-2729

Tim Mount

Cornell University

Department of Agricultural Economics
Ithaca, NY 14853

USA.

Phone: 607-255-4512

Heinz-Ulrich Neue

International Rice Research Institute
Soils Department

P.O. Box 833

Manila

PHILLIPPINES

Fax 63-2-8178470

David Norse

FAO

Room B 637

Via delle Terae de Caracalla
00100 Rome

ITALY

Phone: 39-6-5797-5033

Fax 39-6-5797-5609

S-B.B. Oteng!
Ministry of Research,Science-and Technology
P.O. Box 30568
Nairobi
KENYA
Phone:. 254-2-336173
Fax: —-254-2-333791
Telex: SCIENCETECH

Sangsant Panich

Office of the National Environment Board
Ministry of Science, Technology, and Energy
60/1 SO1 Piboonwatana 7, Rama 6 Road
Bangkock 10400

THAILAND

Phone: 66-2-279-8087

Fax:  66-2-279-0672

Telex: 20838 MINSTEN TH

Miles Parker

Chief Scientists Group
Ministry of Agriculture,
Fisheries, and Food
Nobel House, Room G13
17 Smith Square

London, SWIP 3JR
UNITED KINGDOM
Fax 44-1-238-6700

William Patrick

Center for Wetlands Resources
Louisiana State University
Baton Rouge, LA 70803
USA.

John Patterson

Purdue University

Department of Animal Sciences
3-101 Lilly Hall

West Lafayette, IN 47907
USA.

Phone: 317-494-6508

Page E-6



sound." These approved technologies and practices will be a
technology-based standard, and the parties to the agreement will
be responsible for ensuring that these technologies and practices
are used when hazardous waste is handled and disposed.

To date much of the discussion surrounding approaches for
controlling greenhouse gas emissions has been patterned after the
Montreal Protocol experience. This approach would establish
national limits on the aggregate emissions of the key greenhouse
gases, such as carbon dioxide, methane and nitrous oxide. Each
nation would then have the flexibility of achieving its limit by
reducing its emissions in the most cost effective manner,
including trading among the various gases. This approach has
tremendous appeal due to the maximum amount of flexibility that
it provides and its likely economic advantages.

However, discussion at the April 1990 IPCC Methane Workshop
indicated that the best way to reduce methane emissions may be to
provide incentives to implement encouraging technologies.
Regulatory approaches that command methane reductions could have
major difficulties. These difficulties result from the fact that
methane emission sources have a different character than carbon
dioxide sources and the CFC sources covered by the Montreal
Protocol. Carbon dioxide and CFCs are primarily emitted from
industrial activities with well-defined inputs and emissions
rates. Consequently, without actually analyzing air samples in
the laboratory for carbon dioxide and CFcs, it is relatively easy
to document national emissions as well as emissions from
individual facilities or processes.

Methane, alternatively, is generally emitted by complex and
highly variable biological systems (e.g., rice paddies,
livestock, landfills, biomass burning) and industrial systems
whose inputs and outputs cannot be translated easily into
emissions (coal mines and oil/gas systems). Consequently, for
any given activity, the base level of methane emissions is more
difficult to document than the base levels of emissions of carbon
dioxide and CFCs. Currently, methane emissions rates can only be
documented at individual facilities and locations by performing
detailed and costly atmospheric measurements. These measurements
will generally be valid for a given period of time during which
practices and conditions remain stable. An unexpected geologic
formation, a shift in available feed inputs, or a change in
refuse characteristics can radically alter emissions from coal
mines, cattle and landfills.

This difficulty in accurately estimating levels of methane
emissions from individual sources presents a particular problem
for controlling emissions with national limits. Of primary
concern is that it will be difficult to document baseline
emissions and emissions reductions that are achieved.

31



REFERENCES

Blake, D.R. and F.S. Rowland, "Continuing Worldwide Increase in
Tropospheric Methane, 1978 to 1987," Science, March 4, 1988.

Blake, D.R. and F.S Rowland (1986), “World-wide Increase in
Tropospheric Methane, 1978 - 1983," u: fe) tmos: i

Chemistry, Vol. 4, p. 43-62.

Casada, M.E. and L.M. Safley, Jr. (1990), "Global Methane
Emissions from Livestock and Poultry Manure," presented at the
International Workshop on Methane Emissions, April 9-13, 1990,
Washington, D.C., sponsored by the Environment Agency of Japan
and the U.S. Environmental Protection Agency.

Cicerone, R.J. and R.S. Oremland, "Biogeochemical Aspects of

Atmospheric Methane," Global Biogeochemical Cycles, Vol. 2, No.
4, 299-327, December 1988.

Ehhalt, D.H., R.J. Zander, and R. A. Lamontagne (1983), "On the
Temporal Increase of Tropospheric CH,," Journ Geophysical
Research, Vol. 88, pp. 8442-8446.

EPA, Policy Options for Stabilizing Global Climate, Draft Report
to Congress, D. Tirpak and D. Lashof eds., U.S. Environmental
Protection Agency, Washington, D.C., February 1989.

Fraser, P.J., M.A.K. Khalil, R.A. Rasmussen, and A.J. Crawford
(1981), "Trends of Atmospheric Methane in the Southern

Hemisphere," Geophysical Research Letters, Vol. 8, pp. 1063-1066.

Hansen, J. et al., "Global climate changes as forecast by Goddard
Institute of Space Studies Three-dimensional Model," Journal of

Geophysical Research, Vol. 93, pp. 9341 - 9362, 1988.
Khalil, M.A.K. and R.A. Rasmussen (1982), "Secular Trends of
Atmospheric Methane," Chemosphere, Vol. 11, pp. 877-883.

Khalil, M.A.K. and R.A. Rasmussen (1990), "Atmospheric Methane:
Recent Global Trends," vi 1M. a. ien h: ogy,
Vol. 24, pp. 549-553.

Lashof, D.A. (1989), "The Dynamic Greenhouse: Feedback Processes
That May Influence Future Concentrations of Atmosperic Trace
Gases and Climatic Change," Climatic Change, Vol 14, pp. 213-
242.

Lashof, D.A. and D.R. Ahuja, "Relative Contributions of
Greenhouse Gas Emissions to Global Warming," Nature, Vol 344
(6626), pp. 529-531, april 5, 1990.

63



Exhibit C-1
Methane Generation from Landfills World-wide

United States,
Canada, and
Australia OECD

USSR and
Eastern
Europe

Other

Developing
Countries

Total

Municipal Waste Generation
(kg C/cap/yr)

Percent Paper Products 72
Percent Other 28

Population Considered 272
(mi Lions)

Total Waste Carbon 40
(mi ULion tons/yr)

Fraction landfilled n
(percent)

Waste C Landfilled 7
(million tons/yr)

Methane from Landfilled 19
Municipal Waste

(Teragrams, based on

-5 kg CH4/kg C)

Landfilled Industrial Wastes
(million tons C/yr)

Methane from Landfilled
Industrial Wastes
(Teragrams, based on

~5 kg CH4/kg C)

Methane from Landfilled
Agricultural Wastes

Total Methane from Landfills
(Teragrams)

148 + 30

56 + 21 38

57 37

43 63

471 400

26 5

71 85

27 +17

a“
59

101

12 - 22

30 - 70

Source:

Research, Vol. 92, No. D2, pp. 2181-2187, February 20, 1987.

Bingemer, H.G. and P.J. Crutzen, "The Production of Methane from Solid Wastes,"

Ge ical

Page C-2





consumption of CH, by CH, oxidizing bacteria that exist in the
aerobic zones of the paddy soil environment may significantly
limit CH, fluxes.

Since methanogenesis is a biological process, any factors
influencing the physical, chemical or biological characteristics
of the rice paddy environment will influence CH, production and
emission. Factors affecting CH, fluxes from rice paddies include
soil temperature, redox (oxidation-reduction) potential, supply
of organic matter to the methanogenic bacteria and the
introduction of chemicals (e.g., fertilizer) into the soil.
Variations in local agricultural management practices (such as
the use of organic or mineral fertilizer, incorporation of crop
residues, and different water management systems) can result in
widely different paddy soil environments and hence significantly
affect the CH, flux patterns. These factors are outlined in
detail below.

Soil Temperature. Temperature is known to play an important
role in the rate of activity of soil microorganisms. Holzapfel-
Pschorn and Seiler (1986) report a doubling of CH, emissions from
rice paddies for a soil temperature increase from’ 20°C to 25°C.
Most methanogenic bacteria display optimum rates of production
around 30°C (Neue and Scharpenseel, 1984). Flooding provides a
good environment for CH, production as it produces high
temperatures in the rice paddy soil, typically in the range 25°C
to 35°C.

Redox Potential. It has been shown that methanogenic
bacteria can only function at redox potential levels below
-200 mV and that a correlation exists between CH, emissions and
soil redox potential. When rice paddy soil is flooded, the
following processes ensue; depletion of 0,, reduction of nitrate,
reduction of Mn“ and FeTM*, and finally re ction of sulfate and
methanogenesis. If sufficient organic matter is available, the
low redox potentials necessary for methanogenesis may be
achieved. Waterlogged paddy soils often display the redox range
(<-200 mV) required for CH, production (Exhibit D-4).

Soil pH. Methanogenesis is favored by a neutral (pH=7) or
slightly above neutral pH with the exact optimum pH influenced by
the type of soil (Minami 1989). Flooding acts to stabilize the
soil pH value around neutrality (i.e., increase it for acid soils
and decrease it for alkaline soils).

Substrate and Nutrient Availability. The availability of
oxidizable substrate may have an effect on the pattern of CH,
emissions. Seiler et al. (1984) report seasonal peaks in cH,
fluxes from paddy soils that may correspond to increases in Soil
organic matter content; i.e., peak emissions were observed
following the incorporation of crop residues prior to flooding,

Page 0-6



In developing opportunities for using recovered
methane, the safety of mining operations cannot be
compromised.

Many of the opportunities to make additional reductions
are not justified on the basis of current mining needs,
gas market conditions and investment considerations.
Additional reductions may be justified on an
environmental basis, however, and the environmental
benefits of additional recovery should be examined
further. If the value of reducing methane is
incorporated into economic assessments (i.e., through
the provision of subsidies or low-interest loans) the
amount of economically attractive degasification would
significantly increase.

Additional research and government funding is necessary
to fully develop the potential for using recovered
methane. Work in the following areas is required:

. Technologies that use medium-quality gas and small
amounts of gas (from small mines) should be given
high priority in future research.

. The recovery and use of methane from ventilation
air can potentially be an important source of
methane reductions in the future, as appropriate
technologies are developed and demonstrated.

. Research is necessary on the optimal integration
of utilization technologies and mining operations
in a manner that ensures mine safety and maximizes
gas recovery and use.

° The interrelationship between coal mining,
degasification, and methane utilization should be
explored.

. Innovative ways of coupling mining operations with

methane utilization options should be developed
and implemented.

. Future efforts should emphasize assessing recovery
potential, identifying candidate sites and
developing demonstration projects.

4. Policy Options for Reducing Emissions

4.1

Barriers to methane recovery and use -- such as gas
ownership, reasonable terms of gas or electricity
purchase, and competing environmental goals--should be

41



APPENDIX B

ENERGY-RELATED METHANE EMISSIONS

B.1 Oil and Gas Systems
issions

Understanding the rate of methane (CH,) emissions from oil
and natural gas systems is important because these systems have
been identified as a moderately important source of global CH,
emissions, contributing about 25 to 50 Tg/yr or 6 to 13 percent
of anthropogenic methane emissions. Improved estimates of CH,
emissions from these systems will help improve the estimates of
global CH, emissions and will assist in identifying strategies
for limiting future increases in CH, concentrations.

In addition, understanding these CH, emissions from natural
gas systems is important because natural gas produces less co,
per amount of energy delivered than other major fossil fuels when
burned (see Exhibit B-1), and substituting natural gas for other
fuels (e.g., coal and oil) is being considered as a strategy for
reducing future CO, emissions. For example, displacing an
equivalent amount of coal with 5 tcf of natural gas for electric
power production would reduce the U.S. emissions of CO, from
fossil fuel use by about 6 percent (1 tcf = 1 trillion cubic feet
= 10° cubic feet). However, because CH, is also an effective
greenhouse gas, the beneficial impact of this fuel substitution
on CO, emissions would be significantly diminished (or negated)
if CH, emissions from natural gas systems are large.

The point at which CH, emissions from natural gas systems
negate the beneficial impact of switching to natural gas depends
on a variety of factors, including: emissions of all the
important trace gases during the production, distribution, and
use of the various fuels; the energy conversion efficiency with
which the fuels can be used; and the relative ability of the
various trace gases to contribute to changes in the energy
balance of the Earth. While there is uncertainty about each of
these factors, it appears that CH, emissions on the order of 4 to
10 percent of natural gas throughput would be sufficient to
negate the benefits of switching from oil and coal to natural gas
in major applications, such as electric power production.

Methane is the primary component of natural gas.

Page B-1



3.5 Significant research, analysis, and demonstration will

be necessary to achieve reductions in methane emissions
sufficient to stabilize methane concentrations.

A variety of frameworks may be used to structure
international action for controlling methane emissions.
Economic incentives, market mechanisms, and technology-based
approaches are among the options that should be considered
as alternatives to regulatory "command-and-control"
approaches that require emission rollbacks.

4.1

Methane sources are numerous, diverse, and
geographically dispersed. Additionally, methane is
generally emitted by complex and highly variable
biological and industrial systems whose inputs and
outputs cannot be translated easily into emissions.
Therefore, precise measurement of emissions from
individual locations is difficult.

Incentive-based control strategies under which best
practices are encouraged may be the preferred approach
for reducing methane emissions. This approach may
encompass the wide range of options available for
reducing emissions and may facilitate adaptation among
the diverse and decentralized sources.



ABOUT THIS REPORT

This report is based on workshops sponsored by the Japan
Environment Agency and the United States Environmental Protection
Agency in order to support the Intergovernmental Panel on Climate
Change (IPCC). These workshops examined methane emissions and
opportunities for control of these emissions as follows:

Workshop of the Agricultural, Forestry and Other Human
Activities Subgroup (AFOS)

° flooded rice fields
° livestock

Workshop of the Energy and Industry Subgroup (EIS)

° natural gas systems
° coal mining
° waste management systems

The United States Environmental Protection Agency provided
the necessary support for assembly of this report. It isa
summary of the information presented at the two workshops by
experts in the particular subject areas. The material is
presented for informational purposes and does not represent the
policies of the Japan Environment Agency or the United States
Environmental Protection Agency or any of the other government
agencies of these countries. The list of workshop attendees is
provided in Appendix E.



Brad Rein

U.S. Department of Agriculture
14th and Independence Ave.
Room 3346, S-Bldg.
Washington, D.C. 20520-0900
USA.

Phone: 202-447-2471

Fax: 202-475-5289

Robert Repetto

World Resources Institute
1709 New York Ave, NW
Washington, D.C. 20006
USA.

Phone: 202-638-6300
Fax 202-638-0036

Michael R. Riches

US. Dept. of Energy

ER-76

Atmospheric Climate Research Division
Washington, D.C. 20545

USA.

Phone: 301-353-3264

Fax 301-353-3884

Omnet: M.RICHES

Joseph A. Robinson

The Upjohn Company

Microbiology and Nutrition Research
7922-190-MR

Kalamazoo, MI 49001

USA,

Phone: 616-385-6752

Katsuya Sato

Air Quality Bureau, Environment Agency
1-2-2 Kasumigaseki, ChiyodaKu

Tokyo, 100

JAPAN

Phone: 81-3-580-2164

Fax 81-3-593-1049

Dieter R. Sauerbeck

Institute for Plant Nutrition and Soil Science
Federal Research Centre of Agriculture
Bundesalee 50, D-3300
Braunschweig-Volkenrode

FEDERAL REPUBLIC OF GERMANY
Phone: 49-531-596-303

Fax: 49-15-31-596-814

Wolfgang Seiler

Fraunhofer Institute for Atmospheric Research
Kreuzeckbahnstrabe 19

D-8100 Garmisch-Partenkirchen

FEDERAL REPUBLIC OF GERMANY
Phone: 49-8821-18310

Fax: — 49-8821-73573

Telex: 592474 IFUD

Yasuhiro Shimizu

Environmental Attache

Embassy of Japan

2520 Massachusetts Avenue, NW
Washington, D.C. 20008

USA.

Phone: 202-939-6725

Fax: 202-939-6788

John Sigmon

U.S. Environmental Protection Agency
Office of Research and Development
RD-682

401 M Street, SW

Washington, D.C. 20460

USA.

Phone: 202-382-5783

Fax 202-382-6370

Wesley D. Skidmore
FDA/CVM/HFV-162
5600 Fishers Lane
Rockville, MD 20857
USA.

Phone: 301-443-2977

KA. Smith

The Edinburgh School of Agriculture
Department of Soil Science

West Mains Road

Edinburgh EH93G

SCOTLAND

Stephen D. Sparrow

University of Alaska

Agricultural and Forestry Experiment Station
Fairbanks, AK 99775-0880

USA.

Phone: 907-474-7620

Fax: 907-474-7439

Page E-8



6. FINDINGS FOR COAL MINES

1. Emissions Estimates

1.1

Recent global studies of methane emissions from coal
mining provide "order of magnitude" estimates and
identify those countries with the largest potential
opportunities for methane recovery. There are
currently many uncertainties about the absolute levels
of emissions from this source, however, and about the
contributions of various countries to this total.

Coal mining activities are an important source of
methane emissions on a global scale. Current estimates
generally suggest that coal mining activities emit
about 30-50 million metric tons, although some
estimates are as low as 20 million metric tons and
others are as high as 60 million metric tons. These
emissions are roughly 7 percent of global methane
emissions and approximately 10 percent of global
anthropogenic methane emissions. However, since both
the current estimates and the methodologies which
support them include many uncertainties, more research
is necessary to refine these estimates.

To meet the energy requirements associated with
increased population and additional development, coal
production will likely increase from its current level
of about 5 billion” tons. If coal production grows at
the rate forecast by the International Energy Agency,
production levels could exceed 6 billion tons by 2000.
In many countries, this increase in production will
likely be accompanied by an increase in the proportion
of coal mined in underground mines and the depth of
these mines. This implies that methane emissions from
coal mining could increase by more than 25 percent over
the next decade in many countries.

2. Steps to Improve Emission Estimates

2.1

More research is necessary to refine estimates of
methane emissions from coal mining activities.

14

1 billion equals 1000 million.

38



Raymond C. Pilcher

Raven Ridge Resources Inc.
PO Box 55187

Grand Junction, CO 81505

Tel: 303-245-4088
Fax: 303-245-2514

Tad R. Potter

Pittsburgh Coalbed Methane
Yorum

Suite 201 Roosevelt Building
Pittsburgh, PA 15222

Tel: 412-391-6976
Pax: 412-391-7813

Mr. Robert Preusser
vVP/Engineering and Gas
Operations

Brooklin Union Gas

195 Montague Street
Brooklyn, WY 11201-3631

Tel: 718-403-2525
Fax: 718-522-4766

Peter J. Proudlock
CH(4) International Ltd.
808-48 Street, NE
Calgary, Alberta

Canada T2A 41L9

Tel: 403-273-6296
Fax: 403-273-6296

Gus Quiros

Pacific Gas & Blectric Co.
3400 Crow Canyon Rd.

San Ramon, CA 94583

Tel: 415-973-4813
Fax: 415-973-8147

Howard Reiquan

Dr. Keith M. Richards
BT8U, Harwell Laboratories
Harvell

Didcot, Oxon, OX11 ORA
England

Tel: 0235 43 3586
Fax: 0235 432923
Telex: 83135

Mike Ryan

IcF Incorporated
409 12th Street, SW
Washington, DC 20024

Tel: 703-934-3698
Fax: 703-934-3590

L. M. Safley, Jr.
North Carolina state
University

NCSU, BAB

Box 7625

Raleigh, MC 27695-7625

Tel: 919-737-3121
Fax: 919-737-7760

Peter W. Sage

British Coal Corporation
Coal Research Establishment
Stoke Orchard, Cheltenham
Gloucs. GL52 4RS

England

Tel: England 242 67 3361
Pax: 242 67 2429
Telex: 43568 (CBCRE G)

Dr. Aboud Saghafi
Australian Coal Industry
Research Laboratory
ACIRL, PO Box 9
Corrimal, N.8.W. 2518

Tel: (042) 841711
Fax: (042) 836001

Page E-19



Ruminant animals. CH, is produced as part of the
normal digestive processes that take place in the rumen
of ruminant animals (e.g., cattle, buffalo, sheep,
goats, camels). Crutzen et al. (1986) have performed
the most detailed assessment of ruminant animals as a
source of CH, emissions and estimate that in 1983 total
CH, emissions from managed ruminants (i.e., those kept
by humans) and other domesticated farm animals (pigs,
mules, and horses) were on the order of 73 Tg, with
cattle producing the majority of the emissions (54 Tg).
Emissions from domesticated animals are increasing as
the population of animals increases and as the diets of
those animals increase. Wild ruminants, wild large
herbivores (e.g., elephants), and humans were found to
produce far less CH, (approximately 2 to 6 Tg).

Crutzen et al. indicate that their estimates have an
uncertainty of +15 percent. The uncertainty may be
greater because several components of the calculations
are not known precisely, including: the sizes of the
populations of animals (particularly in developing
countries, which have the largest populations); the
amount and type of feed consumed by the animals (which
influence the CH, emissions rates; see for example,
Blaxter and Clapperton (1965)); and the rate at which
CH, is produced in the rumen. A rigorous evaluation of
these uncertainties has not yet been performed.

Animal wastes. The estimates of emissions from animals
do not include potential CH, emissions associated with
the decomposition of animal wastes. It is well
established that in anaerobic environments methanogenic
bacteria will help to break down animal wastes and
produce CH, (e.g., in a waste lagoon). Such emissions
have been measured (e.g., see Safley and Westerman
(1988)), and may be substantial in locations where
large numbers of animals are managed in confined
locations (e.g., in dairies and feedlots).

Casada and Safley (1990) report an initial estimate
that CH, emissions from animal wastes may be on the
order of 35 Tg per year globally. A substantial
fraction of these emissions are generated by wastes
managed in lagoons from large concentrations of
animals. These emissions are expected to

Page A-3



integrated management approach to irrigation,
fertilizer application, and cultivar selection.
Substantial research, development, and demonstration of
practices must precede any real reductions from this
source.

. Qil and Gas Systems. Technologies have been proven to
reduce CH, venting from oil production facilities. It

has also been suggested that emissions associated with
the USSR gas transmission system could be reduced by
improvements in the construction and operation of the
system.

. Biomass Burning. Biomass burning can be reduced
through fire management programs and widespread use of
alternative agricultural practices. Agricultural
systems traditionally dependent on the removal of
biomass by burning (i.e., long-term shrub-fallow
systems and high-yield grain crops) may be modified to
incorporate the biomass directly into the soil, thereby
improving soil organic matter, in addition to reducing
emissions from burning, or removal for use as an
alternative fuel source.

In addition to the benefits of reduced CH, emissions, it is
important to note that steps taken to reduce ch, emissions often
provide other benefits. For example, recovery of CH, from
landfills also reduces emissions of toxic air pollutants, reduces
odor problems, and produces energy which avoids carbon dioxide
emissions associated with other energy sources. In the
agricultural area, providing nutritional supplements to livestock
which feed on low quality forage and agricultural by-products
increases the productivity of the animals and provides a market
for locally produced supplements.

The appendices that follow discuss the emissions reduction
opportunities from each of the major anthropogenic CH, sources in
greater detail.

A.4 References
Bingemer, H.G. and P.J. Crutzen (1987), "The Production of

Methane from Solid Wastes," Journal of Geophysical Research, Vol.
92, No. D2, pp. 2181-2187, February 20, 1987.

Blake, D.R. (1984), Increasing Concentration of tos}
Methane, 1979-1983, PhD Thesis, University of California, Irvine.



United States Air And EPA/400/9-90/007
Environmental Protection Radiation September 1990
(ANR-445)

SEPA Methane Emissions And
Opportunities For Control

Workshop Results Of
Intergovernmental Panel On
Climate Change

S Printed on Recycled Paper



. 0.8 to 6.3 £t?/1lb - full-sized landfills, projected
from existing short-term data.

According, to Ham and Barlaz (1987), the most likely range is 1.6
to 3.9 ft? of gas per pound of refuse. Note that these values
are for landfill gas, of which CH, constitutes approximately 50
percent; therefore, the most likely value for CH, generation
capacity lies in the range of 0.8 to 2.0 ft” of CH, per pound of
waste. The value assumed by Bingemer and Crutzen (1987) was 2.6
ft” per pound of refuse.

Scientists have also estimated gas generation rates at
landfills, which are expressed in terms of volume of CH, per unit
mass of refuse per unit time. These estimates are typically
based on laboratory studies that attempt to simulate landfill
conditions. Actual field testing is also done in some cases. As
with the gas generation capacity estimates, the estimates of gas
generation rates vary considerably. The following values are
provided by Ham and Barlaz (1987):

. 1.6 x 10° to 0.47 ft? of gas per pound of refuse per
year - based on lysimeters;

. 0.24 to 0.94 £t?/lb/yr - pilot-scale or test landfills;

. 0.01 to 0.63 ft?/lbsyr (typically 0.16 to 0.32
£t°/1b/yr) - field tests at full-size landfills.

Again, these values are for landfill gas, about half of which is
CH,. According to Ham and Barlaz (1987), these rates would be
reached after an initial lag period and continue for 5 to 20
years, followed by a first-order die-off period.

Emission estimates are further complicated because not all
of the CH, generated in a landfill escapes to the atmosphere. As
CH, migrates through the landfill towards the surface, if oxygen
is present, aerobic bacteria may oxidize the CH, into carbon
dioxide and water. Researchers disagree over the significance of
the impact of CH, oxidation on overall emissions. Mancinelli and
McKay (1987) suggest that 10 percent of the CH, generated is
oxidized by aerobic bacteria. Bingemer and Crutzen (1987) cite
flux-chamber measurements taken by Jager and Peters (1985) ata
soil-covered landfill indicating that only 70 percent of the CH,
estimated to have been generated was emitted to the atmosphere.
On the other hand, landfill gas often escapes through the surface
of landfills through fissures and cracks, rather than by
diffusion. This results in less opportunity for oxidation,
implying that a larger percentage of the CH, generated actually
escapes to the atmosphere.

Page C-6



pathway for CH, production in the rumen is believed to be of
minor importance in animals fed adequate and balanced diets
awn and Allison, 1983). Instead, the conversion of hydrogen
or formate and CO, (produced by fermentative bacteria) is
wR ea to be the primary mechanism by which methanogenic
bacteria produce CH, in ruminants.

The creation of CH, in the rumen represents energy which is
subsequently not available to the host animal for maintenance or
growth. Methods of reducing CH, creation in ruminants have been
investigated as part of an overall attempt to improve the
efficiency of rumen metabolism. CH, creating bacteria, however,
play an important role in the complex ecology of the rumen so
that simply eliminating or suppressing them will not "free up"
energy that can be used by the animal.

Because the creation of CH, within the rumen is part of the
partitioning of energy within the animal, CH, emissions from
ruminant animals have been estimated for purposes of
understanding the utilization of energy by ruminant animals.
Various authors have summarized these measurements of CH,
emissions from individual ruminant animals.‘ The rate of CH,
creation can be described in terms of a "CH, yield," which is the
energy content of the CH, produced as a percentage of the food
energy intake of the animal.

A system for describing the food energy intake of ruminant
animals has been developed and is summarized in Exhibit D-5. As
shown in Exhibit D-5, on a "whole-animal basis," the manner in
which the energy intake of an animal is utilized can be defined
as follows:

° gross energy is the total energy intake by the animal
where the energy content of the feed is defined as the
total energy it releases when it is burned;

° digestible energy is the gross energy intake minus the
energy eliminated in feces;

° metabolizable energy is the digestible energy minus the
energy eliminated in urine and CH,; and

° net energy is the metabolizable energy minus the heat
produced by the animal. Net energy is the energy
available to the animal for maintenance and growth.

4 See, for example, Blaxter and Clapperton (1965) and Moe
and Tyrrell (1979).

Page D-11



Phil Malone
GeoMet and seangas
6200 Flintridge Rd.
Fairfield, AL 35064

Tel: 205-785-2913
Pax: 205-785-2937

Charles Masser

U.8. BPA

Energy, Air and Engineering
Research Lab MD62

Research Triangle Park, NC

27708

Tels 919-541-7586
Fax: 919-541-2382

Dr. Denes Masssi

D. Masssi Consulting Services
uta

35 Wynford Hts CRES Apt. 2605
Don Mills On M3C IK9

Canada

Tel: 416-444-4118
Fax: 416-444-4118

Greg Maxwell

Waste Management, Inc.
3003 Butterfield Road
Oak Brook, IL 60521

Tel: 708-572-2484
Fax: 708-620-0548

susan Mayer

IcF Incorporated
9300 Lee Y
Fairfax, VA 22301

Tel: 703-934-3782
Fax: 703-934-9740

Paul McNutt

Dept. of the Interior
Bureau of Land Managesent
18th and C street, NW
Washington, DC 20240

Tel: 202-343-4780

John Meyers

Washington International
Energy Group

2300 MN. Street, NW, Suite 600
Washington, DC 20037

Tel: 202-663-9046
Fax: 202-663-9047

Miao Fen

Professor/Senior Geologist
44, Yanta RD (MN), Xian
Shaanxi Province, 710054
China

Tel: 029-714117 Ext. 337
Fax: 029-719357
Telex: 70037 CMECX CH

Catherine Mitchell

Barth Resources Research
258 Pentonville Rd.
London M1 9JY

England

Tel: 01-278-3833
Fax: 01-278-0955

Tadahisa Miyasaka

Blectric Power Development Co.
1825 K Street, MW, suite 1205
Washington, DC 20006

Tel: 202-429-0670
Fax: 202-429-1660

Page £-17





The understanding of the contribution of landfills to
atmospheric CH, emissions would be improved by research efforts
in a number of areas. These include efforts to

. Understand how the rate of methane emissions is influenced
by key landfill characteristics, such as landfill design and
operation; waste characteristics (e.g., composition;
degradability; and moisture content); landfill size; and
local conditions (e.g., climate and ground cover).

. Characterize current and expected future landfills in terms
of those characteristics that influence methane emissions.

. Obtain field measurements of methane emissions from
landfills in different regions using different management
practices and receiving different types of wastes.
Measurement techniques must be developed to collect these

data.
. Examine how methane oxidation influences methane emissions.
. Develop a carbon balance for landfills that describes the

fate of the carbon added to landfills over time. This
carbon balance should describe: carbon storage; methar2 and
carbon dioxide generation; methane oxidation; and methane
and carbon dioxide emissions. This balance should be
sensitive to various landfill characteristics such as:

waste composition (e.g., lignin/cellulose ratios); moisture
content; and landfill design.

. Develop methods for scaling up limited measurements and data
to develop national and global emissions estimates that
reflect differences in cultures, waste generation, and waste
management practices.

Emissions Reductions

Technologies and practices exist to reduce methane emissions
from landfills by collecting and flaring or utilizing the methane
generated in the landfill. In many circumstances these
technologies and practices appear to be cost effective. Use of
these technologies and practices is believed to reduce methane
emissions by 40 to 70 percent at existing landfills. In new
landfills, it is believed that methane emissions can be reduced
by 70 to 95 percent using currently available technologies and
practices.

In more detail, gas recovery systems use pumps to draw gas
through a system of vertical or horizontal wells buried ina
landfill. The gas is routed to a central facility, where it can

Page C-7



EXHIBIT 9

OPPORTUNITIES TO REDUCE METHANE EMISSIONS

Reductions
Technically Needed for
Feasible Stabilization
Emissions Source/ Reductions by 2000
Reduction Option (ig/yr) (tg/yr) Comments
Landfills: Recover methane as an 30 to 60 per- Half the techni- Emissions are concentrated in
energy source. cent: 7 to cally feasible developed countries. A small
24 Tg. amount: 4 to number of large landfills
12 Tg. account for the majority of
emissions. These emissions can
be controlled profitably or at
low cost.
Coal Mining: Pre-mining drainage 50 percent of One-third of the 80 percent of emissions are
from underground mines using emissions from technically found in six countries.
vertical or horizontal wells. gassy under- feasible amount: Emissions are dominated by a
Recovery and use of gob gas from ground mines: 4 to7 Tg. small number of gassy mines.
longwall mines. Use of 12 to 20 Tg. In some countries emissions can
ventilation air for combustion be recovered profitably. The
air in a turbine. Peoples Republic of China is
the largest coal producer and
may have the largest emissions.
Qil_and natural _gas systems: 50 percent of 75 percent of These emissions estimates are
Control venting and flaring at venting/flaring the technically particularly uncertain. Proven
oil production facilities and emissions: 7 Tg. feasible vent- technologies are currently in
improve the transmission system 60 to 80 percent —_ing/flaring use that Limit emissions at oil
in the USSR. of USSR trans- emissions reduc- production facilities. USSR
mission losses: tion: 5 Tg. 50 transmission emissions may be
7 to 19 Tg. percent of the larger than the 3 to 6 percent
transmission assumed here, although precise

Livestock: Improve animal
productivity through strategic
supplementation and productivity
enhancing agents.

emissions reduc- data are lacking. Funding
tion: 4 to9 Tg. mechanisms for improving the
USSR transmission system are

needed.

25 to 75 percent 20 to 35 percent Bovine somatotropin (bST) and
reduction in of the techni- fertility-enhancing techno-
emissions per cally feasible logies will improve producti-
unit of product: amount: 3 to vity in developed countries.
15 to 25 Tg at 91g. Diet changes may yield addi-
current pro- tional reductions. Strategic
duction levels. supplementation of cattle

feeding on poor quality forages
will improve productivity and
reduce emissions. These
programs are cost effective in
their own right.

Continued

26



Previous assessments of CH, emissions have estimated
emissions from natural gas systems based on the assumption that 2
to 4 percent of annual throughput is emitted. Some reports have
indicated, though, that emissions could exceed these levels in
some parts of the world. At these levels of emissions, the
benefit of substituting natural gas for other fossil fuels would
be substantially diminished. All the emissions estimates have
recognized, however, that little data are available upon which to
base these estimates. Consequently, it is clear that improved
data are needed to assess adequately the potential role that fuel
substitution could play in strategies for reducing CO, emissions
in the U.S. and other countries.

Several estimates of CH, emissions from oil and natural gas
systems have been made in the course of estimating global CH,
emissions from all sources:

. Sheppard, et al. (1982): venting emissions of 30 Tg/yr
and distribution emissions of 20 Tg/yr. Sheppard, et.
al. state: "Current flaring and venting of natural gas
is [130 Tg/year]; thus because of its high value as a
fuel and chemical feedstock we assume that less than
25% of the vented natural gas. . . is released into the
atmosphere. . . . An additional leakage source might be
from distribution systems which we assume to be as
large as 2%. . ."

. Bolle, Seiler and Bolin (1986): emissions of 35 Tg/yr.
Bolle, Seiler and Bolin's estimates are based on
“assuming loss rates of natural gas to be 3-4%."

° Crutzen (1987): emissions of 33 Tg/yr. Crutzen uses a
4 percent loss rate.

. Cicerone and Oremland (1988): venting emissions of 14
Tg/yr and distribution emissions of 31 Tg/yr. Cicerone
and Oremland sum up the derivation of natural gas
emission estimates as follows: "Previous
estimates . . . appear to have used figures for annual
production and assumed loss rates of 2-4%. Loss
figures such as these are usually from industrial
representatives who mean them to include all
unaccounted for gas . . . Unaccounted for gas is
typically 2 to 2.5 percent of total production for the
United States, but such figures are poorly documented.
Other factors that have not been considered previously
are emissions from oil exploration and recovery, and
from venting and incomplete gas wells and losses due to
explosive events."

Page B-3



ICF Resources (1990), Methane Emissions to t spher rol

Coal Mining, draft report prepared for the U.S. Environmental

Protection Agency Office of Air and Radiation by ICF Resources
Incorporated.

Marland, G. and R.M. Rotty (1984), "Carbon Dioxide Emissions from
Fossil Fuels: A Procedure for Estimation and Results for 1950-
1982," Tellus, Vol. 36B, pp. 232-261.

Matthews, E. and I. Fung (1987), "Methane Emissions from Natural
Wetlands: Global Distribution, Area, and Environmental

Characteristics of Sources," Global Biogeochemical Cycles, Vol.
1, pp. 61-86.

Minami, K. (1989), "Effects of Agricultural Management on Methane
Emissions from Rice Paddies," Proceedings of the Workshop on
Greenhouse Gas Emissions from Agricultural Systems of the IPCC
Response Strategies Working Group, December 12-14.

PG&E (Pacific Gas and Electric) (1989), "Unaccounted for Gas
Project," Draft Report, November.

Prinn, R. et al. (1987), "Atmospheric trends in methylchloroform
and the global average for the hydroxyl radical," Science,
Vol. 238, pp. 945-950.

PSI (Pipeline Systems Incorporated) Tilkicioglu, B.H., and D.R.
Winters (1990), "Annual Methane Emission Estimate of the Natural
Gas and Petroleum Systems in the United States," prepared for the
U.S. Environmental Protection Agency Office of Air and Radiation
by Pipeline Systems Incorporated.

Safley, M.L. and P.W. Westerman (1988), "Biogas Production from
Anaerobic Lagoons," Biological Wastes, Vol. 23, pp. 181-193.

Sebacher, D.I., R.C. Harriss, K.B. Bartlett, S.M. Sebacher, and
S.S. Grice (1986), "Atmospheric Methane Sources: Alaskan Tundra
Bogs, an Alpine Fen, and a Subarctic Boreal Marsh," Tellus, Vol.
38B, p. 1-10.

Seiler, W. (1984), "Contribution of Biological Processes to the
Global Budget of CH, in the Atmosphere." In: Klug and C. Reddy
(eds.), ‘urrent Perspectives in Microbial ology, M. American
Society for Microbiology, Washington, D.C. pp. 468-477.

Seiler, W. (1989), "Role of Rice Cultivation in Global Emissions
of Trace Gases," Proceedings of the Workshop on Greenhouse Gas
Emissions from Agricultural Systems of the IPCC Response
Strategies Working Group, December 12-14.

Page A-14



EXHIBIT 1

RADIATIVE FORCING ADDED IN THE 1980s

Carbon Dioxide Methane

55%

Source:

15%

CFCs 11 and 12
17%

Nitrous Oxide Other CFCs
6% 7%

The observed increases in the atmospheric
concentrations of key greenhouse gases were used
to estimate an increase in the "radiative forcing"
of the atmosphere. The radiative forcing refers
to the extent to which the constituents in the
atmosphere are able to capture infrared radiation
(IR) given off by the Earth. By increasing the
radiative forcing of the atmosphere, the
greenhouse gases are expected to cause global
warming.

The analysis indicates that methane contributed
about 15 percent of the increase in radiative
forcing observed in the 1980s.

IPCC Working Group 1 Science Assessment Report



8. FINDINGS FOR RICE CULTIVATION

Atmospheric levels of methane are increasing and will affect
tropospheric air quality and global climate change.

1.1

Methane is an important greenhouse gas that, based on
model calculations, accounts for about 20% of the
current increase in commitment to global warming.

The methane concentration in the troposphere is about
1.75 parts per million (ppm) at present and is
currently increasing by 0.8%-1.0% (10 to 16 ppbv) per
year. This rate of increase is well characterized for
the recent past. In addition, ice core data show that
methane concentrations have more than doubled in the
last two centuries and that they are now substantially
higher than they have been in the past 160,000 years.

Increasing emissions of methane are the primary cause
of increasing methane concentrations. Reduction in the
rate of methane destruction in the atmosphere (possibly
due to changes in OH number density associated with
increasing emissions of carbon monoxide) is also a
factor.

Continued increases in methane concentrations will lead
to changes in the distribution and concentration of
tropospheric ozone, which is a key substance in
tropospheric chemistry, and could possibly threaten
human health and the environment. Furthermore, there
is concern that increasing methane concentrations will
enhance the formation of stratospheric polar clouds,
thus contributing to the polar stratospheric ozone
depletion.

Although uncertainty exists as to the exact
contribution of each source to the annual global
emissions of 400 to 600 teragrams (Tg) of methane, it
is clear that the major anthropogenic sources include:
rice fields; ruminant animals; landfills; biomass
burning (e.g., shifting agriculture); venting and
incomplete flaring of gas during oil exploration and
extraction; leakage of natural gas during natural gas
extraction and distribution; and coal mining. Current
estimates indicate that anthropogenic sources account
for about 60%-70% of current methane emissions. The

50



Additional work is necessary to improve these estimates.
Some possible areas for further research are listed below:

. Data Collection: Additional data are needed for most
countries on coal CH, contents, CH, emissions at a
group of mines which’ represent different coal types,
mining depths and mining methods, and coal production.
Using these data, country-specific relationships
between coal CH, content and mining emissions can be
developed.

. Surface Mines: Currently, there is limited information
on CH, emissions from surface mines because these
emissions pose lower safety hazards. Research is
necessary to measure CH, emission rates at surface
mines and to develop methods for estimating global CH,
emissions from surface mines more accurately.

. Geologic Understanding: Additional research is also
necessary to improve understanding of the mechanisms by
which CH, is released during coal mining and the
geologic’ characteristics that influence the amount of
CH, stored in the coal and its surrounding strata.

In addition to these areas, other important research issues will
arise as more information is compiled on CH, emissions in various
countries.

eductions: hane_ Co: Recov

In order to reduce CH, emissions from coal mining, it is
necessary to employ two types of technology: degasification and
utilization technologies. Degasification technologies are
required to recover the CH, from the coal mine, and utilization
technologies are necessary’ as an alternative to venting the CH,
into the atmosphere.

Degasification

A number of degasification technologies have been
demonstrated, and many mines currently employ them to enhance
mine safety and to reduce operating costs at the mine. Based on
experience to date, it appears that up to 50 percent of the CH,
released during coal mining could be recovered by degasification
systems used before and during mining activities. Some of these
technologies require drilling boreholes from inside the mine
works and transporting recovered CH, to the surface, while in
other cases wells are drilled from the surface to the coal seam
and CH, is pumped out. To date, these technologies have been
used to improve mine safety, and little attention has been paid
to the recovery and use of the CH, produced. In many cases, the



increase in the future as the practice of managing
large concentrations of animals increases. Additional
analysis and measurements are required to improve the
estimate of these emissions.

Rice paddies. CH, emissions from submerged rice paddy
soils have been measured in the field at several
locations (e.g.: Cicerone and Shetter (1981); Cicerone,
Shetter, and Delwiche (1983); Seiler et al. (1984);
Holzapfel-Pschorn and Seiler (1986), Kahlil et. al.
(1989), Seiler (1989), Minami (1989), and
Washida(1989)). Methanogenic bacteria in the soils
produce CH, that is transported out of the soils by the
rice plant’ as well as by diffusion.

Bolle, Seiler, and Bolin (1986) estimate that CH,
emissions from rice paddies are about 70 to 170 Tg per
year. Cicerone and Oremland report a similar range
with a central estimate of 110 Tg per year. Most
recently, Seiler (1989) estimates a range of 70 to 110
Tg, using measurements from work performed in China and
accounting for varying lengths of growing periods and
varying seasonal affects.

Methane emissions from rice paddies will likely
increase over the next decade because the harvested
paddy area is expected to increase by 25 percent by the
end of this century.

Natural wetlands (tundra, bogs, swamps). Natural
wetlands are believed to be a large source of CH,
emissions. As in submerged paddy soils, methanogenic
bacteria produce CH,. Based on analyses of various
assessments of the éxtent of various wetlands around
the world and rates of CH, emissions from various types
of wetlands (e.g., Sebacher et al. (1986) and Harriss
et al. (1985)), Matthews and Fung (1987) estimate these
emissions to be about 115 Tg per year. Cicerone and
Oremland report a subjective range of 100 to 200 Tg per
year around this estimate, indicating that the total
emissions from this source are quite uncertain.

Coal Mining. CH, is found to occur naturally in coal
seams, having been formed while the coal itself was
formed. When coal is mined from underground seams, CH,
is released. The amounts released vary by the type of
coal and the depth of the coal seam. CH, may also be
released when shallow deposits are mined (i.e.,
surface-mined coal), although these quantities may be
relatively low.

Page A-S



An incentive-based approach that promotes encouraging
technologies or practices was identified as one alternative
method for addressing methane emissions. Under this approach the
parties to the agreement could identify those technologies and
practices that are preferred for controlling emissions. National
and international bodies (e.g., under a UNEP program) could
participate in the process of identifying the technologies and
practices. Once identified and adopted, the parties to the
agreement would be responsible for promoting the implementation
of the applicable practices and technologies in their countries.
The preferred technologies and practices would vary, depending on
the local resources and circumstances.

A major advantage of the incentives for technology approach
is that compliance with the control requirements can be more
easily monitored. Parties that are complying will have installed
equipment or will have instituted practices that can be observed.
Consequently, detailed measurements of methane emissions from
individual locations would not be required.

Based on the discussion at the April Workshop, the potential
use of a technology approach for controlling methane emissions
could complement a comprehensive approach and should be explored.
Efforts to structure an approach for controlling methane
emissions must also recognize the importance of international
cooperation. No single country will provide the necessary
reductions in methane emissions to stabilize atmospheric :
concentrations, just as no single source will. Strategies need
to be developed which include all countries and which will
achieve the necessary reductions while promoting economic growth
and agricultural productivity. To achieve a high level of
international participation in methane reducing activities,
technology transfer programs and joint funding mechanisms will
need to be explored and developed.

4.2 Research Needs

Significant research, analysis, demonstration and proof of
concepts is required in order to achieve the real reductions in
methane emissions in the next 10 years that are needed to
stabilize methane concentrations. In particular, the promising
opportunities for reducing emissions must be documented and in
some cases demonstrated in the field. These efforts should be
initiated as soon as practical so that an internationally-
recognized set of data that describe opportunities to reduce
methane emissions can be developed.

Examples of the research needed include:

. Documentation of the techniques that can be used to
recover methane from coalbeds in advance of mining and

32



anaerobic conditions and the extent to which these
wastes are decomposed to methane.

Estimates of methane emissions from these systems have
been developed for a number of different countries or
regions of the world as shown in the following table.

Methane Emissions from Waste Management Systems
(million metric tons)

Landfills Animal. Wastewater
Region/Country Wastes Treatment
Canada 1.8 +3 -.6 ?
Japan 0.17 - 0.02
Oceania 1.25 1-2 ?
USA 8-18 2-5 ?
Western Europe ? 3-8 ?
USSR and
Eastern Europe 5-8 5-12 ?
Developing
Countries 4-7 10-19 ?
Global Total 25-40 20-40 20-25

1.3 Methane emissions from waste management systems could
likely double by 2025 with continued population and
economic growth, assuming the continuation in ongoing
trends in waste management practices.

44



-- solid storage;

-- deep pit stacking;

-- litter;

-- paddock;

- liquid/slurry storage;
-- anaerobic lagoon;

-- pit storage;

- anaerobic digester;

- compost; and

-- burned for fuel.

Emissions Realized. For each waste treatment system an
estimate was made of the portion of the maximum
potential CH, emissions that is actually achieved. For
example, 90 percent of the maximum potential emissions
may be achieved if the waste is managed in an anaerobic
lagoon. Alternatively, only 5 percent of the maximum
may be realized if the waste is spread daily.

Using these estimates, the total global CH, emissions from animal
wastes was estimated. Using the estimates of the amount of waste
handled in each of the waste handling systems, the CH, emissions
that are actually realized were estimated.

These preliminary estimates put global CH, emissions from
animal wastes at about 35 Tg per year. This total is comprised
of the following:

Beef and dairy cattle: 19 Tg per year;
Swine: 9 Tg per year;
Buffalo: 3 Tg per year; and

Other: 4 Tg per year.

These estimates divide out regionally as follows:

North America: 4 Tg per year;
Western Europe: 7 Tg;
Eastern Europe: 10 Tg;
Oceania: 1 Tg;

Latin America: 3 Tg;

Africa: 2 Tg;

Near East and Mediterranean: 1 Tg; and

Page C-15



Analyses of policies that will promote the reduction of
methane emissions from waste management systems are
necessary, including analyses of policies that:

. promote capacity expansion in the recycling and
recovery industries;

. encourage methane recovery and utilization, for
example by:

-- setting fair-market sales prices for
recovered methane or electricity produced
from recovered methane;

-- eliminating institutional barriers that limit
competition in electricity production,
transportation, and sales;

-- increasing the costs of producing commercial
energy from fossil sources, e.g., by imposing
carbon dioxide emissions fees;

-- providing financial incentives for recovering
methane, e.g., by providing tax incentives;
and

-- creating a market for energy produced from

recovered methane, e.g., by setting goals for
non-fossil fuel energy production.

49



propionate production in the rumen and/or defaunating the rumen
should also be explored.

These various opportunities for reducing CH, emissions from
animals must be evaluated under field conditions’ to document the
impact that they will have on CH, emissions.

D.3 Biomass Burning

Emissi

CH, is produced by incomplete combustion during biomass
burning. The amount of CH, produced depends on the material
burned and the degree of combustion. Estimates range from 50 to
100 Tg of CH, annually (Cicerone and Oremland, 1988). This
represents 10 to 20 percent of total annual CH, emissions. While
a few studies have attempted to understand and’ measure CH,
emissions from biomass burning (Crutzen et al., 1979, 1985),
extrapolation to a global estimate is difficult because of the
lack of global data on area burned, fire frequency, and
characteristics of fires.

Biomass is burned to convert forest and savannah ecosystems
into agricultural or pasture land, to return nutrients to the
soil, to reduce shrubs on rotational fallow lands, or to remove
crop residues. In all instances associated with biomass burning,
emissions of greenhouse gases are not well estimated and no
consistent measurement techniques are now in use. Furthermore,
no estimates have separated temperate from tropical sources.
Currently, agricultural burning, due to shifting agriculture and
burning of agricultural wastes, is estimated to account for over
50 percent of the biomass burned annually. The feasibility of
monitoring fires from space will improve these estimates
significantly.

ssions Redui

Biomass burning can be reduced through fire management
programs and widespread use of alternative agricultural
practices. Agricultural systems traditionally dependent on the
removal of biomass by burning (i.e., long-term shrub-fallow
systems and high-yield grain crops) may be modified to
incorporate the biomass directly into the soil, thereby improving
soil organic matter, in addition to reducing emissions from
burning, or removal for use as an alternative fuel source.

Conversion of forest land to agricultural land may be
reduced by adopting sustainable agricultural practices which
optimize yields, or adopting intensive practices on suitable

Page 0-18



2. Steps to Improve Emissions Estimates

2.1

. Substantial uncertainty remains in methane
emissions from landfills. To improve the understanding
of these emissions, research is required to:

. Understand how the rate of methane emissions is
influenced by key landfill characteristics, such
as landfill design and operation; waste
characteristics (e.g., composition; degradability;
and moisture content); landfill size; and local
conditions (e.g., climate and ground cover).

. Characterize current and expected future landfills
in terms of those characteristics that influence
methane emissions.

. Obtain field measurements of methane emissions
from landfills in different regions using
different management practices and receiving
different types of wastes. Measurement techniques
must be developed to collect these data.

. Examine how methane oxidation influences methane
emissions.
. Develop a carbon balance for landfills that

describes the fate of the carbon added to
landfills over time. This carbon balance should
describe: carbon storage; methane and carbon
dioxide generation; methane oxidation; and methane
and carbon dioxide emissions. This balance should
be sensitive to various landfill characteristics
such as: waste composition (e.g., lignin/cellu-
lose ratios); moisture content; and landfill
design.

. Develop methods for scaling up limited
measurements and data to develop national and
global emissions estimates that reflect
differences in cultures, waste generation, and
waste management practices.

Wi water atment S ms. The management of
wastewater effluent from domestic, commercial, and
industrial facilities has the potential to produce
globally significant amounts of methane emissions.
While in many cases wastewater is managed in a manner
that is presumed to produce negligible methane
emissions, emissions data from individual facilities in
developed and developing countries indicate that
emissions are large in certain circumstances. To

45



|

Wastewater Treatment Lagoons. CH, emissions from

wastewater treatment lagoons have not been published.
CH, emissions have been measured from individual
lagoons and other wastewater treatment facilities. The
CH, is produced by the anaerobic decomposition of
organic matter that is found in the wastewater stream.

Estimates at the IPCC Workshop indicated that CH,
emissions from wastewater treatment lagoons may be on
the order of 20 to 25 Tg per year. It was suggested
that emissions are principally expected at specific
facilities with wastewater that has a high organic
matter content, such as food processing facilities.

Other sources of CH, emissions. Oceans and freshwater
have been estimated to be small sources of CH,

emissions (Ehhalt (1974)). However, Cicerone’ and
Oremland indicate that the basis for Ehhalt's estimates
are dated, and that recent increases in the atmospheric
abundance of CH, necessitates that these estimates be
revisited.

Zimmerman et al. (1982) identified termites as a
potentially large source of CH, emissions. As occurs
in ruminant animals, bacteria within termites produce
CH, as part of the termite's digestive process. Given
the large number of types of termites, and the
uncertainties associated with the sizes of their
populations, the emissions from termites is extremely
uncertain. Oremland and Cicerone report 40 Tg per year
of emissions, with a range of 10 to 100 Tg.

Methane hydrates (CH, molecules trapped in water
molecule structures) occur in coastal sediments and
permafrost (see for example, Revelle (1983) for a
review). It has been hypothesized that global warming
could lead to the release of large quantities of CH,
from these structures. Current emissions from this
source are not well quantified, and potential future
emissions (associated with a global warming) remain
speculative.

Emissions from these sources are expected to continue
increasing over the next decades. Projections of methane
emissions from the major energy-related and agricultural sources
are provided in Exhibit A-2 and Exhibit A-3.

Given this overview of sources of CH, emissions, it is clear
that increasing emissions from human activities are contributing
to the observed increases in CH, concentrations. Because of

Page A-8



EXHIBIT B-1

CO, EMISSIONS FROM FOSSIL FUEL USE

Fuel Type Carbon Content Energy Content C02 Emissions
(percent) (Btu/kg) (kg/MMBtu)
Natural Gas 72.8% 48,900 54
Crude Oil
API 31 85.3% 42,950 73
API 14 83.7% 41,350 74
Diesel #2 87.4% 42,500 75
Diesel #3 90.0% 40,250 83
Gasoline 84.6% 45,800 68
Methanol 37.5% 21,500 64
Bituminous Coal
Low Volatility 59.6% 23,100 98
High Volatility 79.5% 30,900 98

1 Btu = 1 British thermal unit = 1.054 x 10° joules = 2.93 x 10%
kilowatt-hours

MMBtu = 10° Btu

Sources:

Marland, G. and R.M. Rotty (1984), "Carbon Dioxide Emissions
from Fossil Fuels: A Procedure for Estimation and Results for
1950-1982," Tellus, Vol. 36B, pp. 232-261.

Unnasch, S. and C.B. Moyer (1989), "Comparing the Impact of
Different Transportation Fuels on the Greenhouse Effect,"
prepared for the California Energy Commission by Acurex
Corporation, March 1989.

Page B-2



. One of the most important goals of future research
will be to improve the methane emission factors
that relate the methane content of the mined coal
to the amount of methane emitted from the mine.
Among the variables that should be investigated
are: depth and rank of coal, geologic and
erosional conditions, mine type (underground or
surface), mining method (room and pillar or
longwall), and age of mine.

. Different models should be developed to
approximate emissions in different mining
environments and in different coal basins and/or
countries.

These estimates should be further refined by pursuing
other research areas, including: (1) improving the
instrumentation and techniques used in measuring
methane emissions and in-situ gas content; (2)
improving data quality (i.e., by collecting better data
on methane emissions through ventilation air and
degasification systems; (3) improving models for
predicting emissions; (4) assessing the relationship
between mining practices and emissions; (5) refining
estimates of methane emissions from surface mining
activities; and (6) investigating emission levels from
abandoned mines.

The methodology used in future studies of methane
emissions from coal mining should be clearly documented
so that it can be verified by independent analysis.
Further, attempts should be made to standardize methane
emission measurement methods and estimation techniques
to ensure that studies conducted by different
researchers are comparable. To this end, consideration
should be given to establishing a collaborative
international data base on coal and mining
characteristics and methane emissions to facilitate the
development of global emission estimates.

To the extent financial resources are limited, future
work should focus on those countries where
opportunities for recovering methane from coal mining
are likely to be large. These countries can be
identified based on the "order of magnitude" emission
estimates in preliminary studies and based on industry
information about the relative gassiness of various
coal mines.

Methane emissions during coal utilization should also
be assessed and opportunities for reducing these
emissions explored as appropriate. While methane

39



Application of Mineral Fertilizer. Due to the nature of the

reduction sequence in flooded soils, the addition of chemicals
such as nitrate or sulfate may suppress CH, production. Since
the reduction of these chemicals takes place at potential levels
above that required for methanogenesis, the methanogenic bacteria
cannot function until nitrate and sulfate reductions are complete
and the redox potential has fallen below -200mV. In addition,
the presence of sulfate may inhibit CH, production due to
competition for substrates between the’ sulfate reducing bacteria
and methanogens, and due to the possibility that CH, is oxidized
to CO, by the sulfate reducing bacteria (see Yagi and Minami 1989
and Bouwman 1989).

Early studies indicated an increase in CH, emissions following
the application of mineral fertilizer (Cicerone and Shetter
1981). However, Yagi and Minami (1989) found a short but
profound decline in methane emissions following mineral
amendments. Other recent work indicates that the relationship
between CH, flux and mineral fertilizer is a complex one
depending on rate and mode of application (e.g., incorporation
vs. surface application), (Schutz et al. 1989). In particular,
the effects of nitrate and sulfate in raising the soil redox
potential and possibly suppressing methanogenesis need to be
further investigated. It should also be noted that the processes
of nitrification and denitrification in soils fertilized with
nitrogen fertilizer lead to the evolution of the greenhouse gas,
nitrous oxide.

High Yield Plant Varieties. The Green Revolution of the

1960's resulted in high yield varieties with shorter growing
seasons that have helped to reduce the volume of CH, produced per
unit of rice. The shorter growing season, however, allows
multiple plantings, thus increased adoption of such varieties may
cause an increase in total CH, emissions.

is for Re: ing Emi

Due to the importance of rice as a food staple, it is
necessary to develop emission reductions options that also
maintain the productivity of the rice paddies. It is believed
that this can be accomplished through a comprehensive approach
including better water management, efficient use of fertilizers,
selection of cultivars, and other management practices, and that
emissions can by reduced by 10 to 30 percent.

A great deal of additional information is needed on CH,
emissions from rice paddies in order to develop reliable options
for stabilizing or reducing atmospheric CH, concentrations.
Improved understanding of the processes contributing to CH,
emissions from flooded rice fields can only be achieved by’

Page 0-9



include: vegetable and fruit processing plants; meat
packing plants and slaughter houses; sugar processing
Plants; distilleries; and creameries.

. As a general rule, one can expect about 300 liters
(0.22 kilograms) of CH, per 10° mg of BOD.

Based on these assessments, and an inventory of wastewater
lagoons in the Kingdom of Thailand, CH, emissions from wastewater
lagoons in Thailand was estimated at 0.5 Tg per year. Although
few data are available, using the Thai estimates as a guide it
may be estimated that global emissions are about 20 to 25 Tg per
year globally.

An inventory of food processing facilities and their methods
of wastewater treatment is required to estimate emissions from
this source more precisely. These emissions will also be a good
candidate for control because the CH, can be captured easily and
used as a fuel at the processing plant. Such systems have been
demonstrated and it is recommended that they be used more widely.

c.3 Animal Wastes
Emission

Animal wastes provide a large potential source of CH,
emissions (Gibbs et al., 1989). Most animal wastes contain
organic material. If this material is decomposed under suitable
anaerobic conditions, methanogenic bacteria may produce
considerable amounts of CH,.

The potential for animal wastes to produce CH, may be
expressed in terms of the CH generated per kilogram of volatile
solids (VS) of waste material. Exhibit C-2 presents values in
the literature for the potential amounts of CH, produced per
kilogram of VS in different animal wastes. As shown in the
exhibit, these values range from .17 to .49 cubic meters (m3) of
CH, per kilogram of vS.

2 volatile solids are that part of the waste that is
combustible.

Page C-11



In general, estimates of global CH, fluxes from rice paddies
have been based on measurements in temperate regions; however,
more than 90 percent of the world's rice cropping area lies in
the Far East where environmental conditions and agricultural
Management practices differ significantly. Little data are
available on CH, emissions from these areas, but recent studies
have been conducted in China by Seiler et al. (1989). These
measurements yield a global estimate for emissions from paddies
of 70-110 Tg of CH,/year (mean of 90 Tg of CH,/year). In
addition, a 30 day study by Khalil et. al. (1989) at zu in
China measured local CH, fluxes in the range 2-240 mg/m*/hr, much
higher estimates than those observed by previous studies in
Europe. In the absence of more comprehensive field studies from
Asia, however, even the more recent estimates of global CH,
emissions from rice must be regarded as uncertain.

Regardless of the current uncertainties, it is likely that
global emissions of CH, from rice cultivation will increase as
the total rice cropping area worldwide increases to meet the
growing demand for rice. Based on projections of global
population levels, it is estimated that the demand for rice will
increase by 50% over the next 30 years, from 440 million tons in
1985 to 680 million tons by 2020. (Exhibit D-1 and Exhibit D-2).
As 90 percent of rice production is from wetland rice (including
irrigated, rainfed and deepwater rice), wetland rice production
is likely to be expanded and intensified in rice growing areas.
In addition, since constraints exist on the potential global land
area available for cropping, it seems likely that the projected
increases in rice production will also be met by shifts in rice
production systems, e.g., conversion of rainfed rice lands to
irrigated rice lands which are more productive and which may also
emit more CH,.

Part of the uncertainty in global estimates of CH, emissions
from rice cultivation is due to the sensitivity of CH, flux
patterns to environmental conditions. CH, is produced in flooded
rice paddy soil by the anaerobic decomposition of organic matter.
The CH,-generating (methanogenic) bacteria involved are strict
anaerobes and require highly reduced conditions for growth. Rice
paddy soils, offering conditions of oxygen depletion, moisture,
and high organic substrate levels present ideal environments for
the proliferation of such methanogens. Recognized substrates
metabolized by methanogenic bacteria include hydrogen reduction
of CO,, acetate, formate, methanol, methylated amines and Co
(Cicerone and Oremland, 1988). The main pathways of CH
production using these substrates are presented in Exhibit D-3.

Field studies indicate that the major portion of the CH,
released to the atmosphere (over 90 percent) is transported
through the rice plants and that the escape of CH, by ebullition
(bubbling) and diffusion through the water column is less
significant. Furthermore, not all the CH, produced in paddy
soils may be emitted to the atmosphere; for example, the

Page 0-2



EXHIBIT D-4

Waterlogged Soil

Highly Reduced Moderat Oxidized
Reduced nad

Reduced
Fe3*—e Fe2*
— ma2*
so s* NO3-PNo
CO, >CH, / O,-eH9
l
‘ re th _

7-300 -200 -100 © +100 +200 +300 +400 +500 +4600 +700

Oxidation-Reduction or Redox Potential, Millivoits
(Corrected to pH 7)

The critical redox potential at which oxidized inorganic
redox systems begin to undergo reduction in flooded soils.

Source: W. Patrick (1989)

Page 0-7



Merritt W. Sprague
U.S. Dept. of Interior
Office of Policy Analysis
18th and C Streets, NW
Washington, D.C. 20240
USA.

Phone: 202-343-4939

Norton D. Strommen

USS. Dept. of Agriculture

World Agricultural Outlook Board
Room 5133 S. Bldg.

Washington, D.C. 20250

USA.

Phone: 202-447-9805

Fax: 202-472-5805

Ir. Aca Sugandhy

Assistant Minister for Ministry
of Population and Environment
Jalan Merdeka Barat 15 B
Jakarta Pusat

INDONESIA

Phone: 62-21-374-307

Fax: — 62-21-380-2183

Parv Suntharalingam
ICF Inc.

9300 Lee Highway
Fairfax, VA 22031-1207
USA.

Phone: 703-934-3233
Fax: 703-934-9740

Robert J. Swart
National Institute of Public Health
and Environmental Protection

Laboratory for Waste Materials and Emissions

P.O. Box 1, 3720 BA
Bilthoven

THE NETHERLANDS
Phone: 31-30-743-026
Fax: — 31-30-250-740
Telex: 47215 RIUM NL

David Swift

Colorado State University
Natural Resources Ecology Lab
Fort Collins, CO 80523
USA.

Phone: 303-491-1643

George Thurtell

University of Guelph

Department of Land Resource Science
Guelph, Ontario NIG2W1

CANADA

Dennis Tirpak

U.S. Environmental Protection Agency
PM-221

401 M Street, SW

Washington, D.C. 20460

USA.

Phone: 202-475-8825

MCC. Trexler

World Resources Institute
1709 New York Avenue, NW
Washington, D.C. 20006
USA.

Phone: 202-638-6300

Fax 202-638-0036

Henry Tyrrell

USDA Ruminant Nutrition Lab
BARC-East

Beltsville, MD 20705

USA.

Phone: 301-344-2409

K. Shaine Tyson

Solar Energy Research Institute
1617 Cole Boulevard

Golden, CO 80401

USA.

Phone: 303-231-1316

Fax 303-231-1199

G.K. Veeresh

University of Agricultural Science
Division of Plant and Soil Science
UAS. G.K.U.K. Bangalore 560065
INDIA

Phone: 91-812-330-153

Fax 91-812-320-840

Telex: 8458393 UASKIN



Gokhan Dincel

Ministry of Energy and Natural
Resources

Konyayolu, Bestepe

ankara Turkey

Tel: 90-402136951
Fax: 90-4-2236984

Bettye F. Dixon

The Australian Gas Association
7 Moore st.

Canberra 2600

Australia

Tel: 61 62 473955
Pax: 61 62 497402
Telex: AA 62137

Charles A. Dixon

Jim Walter Resources, Inc.
Route 1, Box 133
Brookwood, AL 35124

Tel: 205-556-6000

Salwa El Bussioni

Mine Safety and Health Admin.
4015 Wilson Blvd.

Arlington, VA 22203

Tel: 703-235-1915

8Bven-Olov Ericson
Vattenfall/UM
8-162 87 Vallingby
Sweden

Tel: +46 8 7397065
Pax: +468 374840
Telex: 19653 SVTELVXS

Ken Feldman

Office of Energy/USAID
8A-18, Room 508
Washington, DC 20523-1810

Tel: 202-875-4052
Fax: 202-875-4053

Bruce Findlay

Canadian Climate Centre
Environment Canada (AES)
4905 Dufferin street
Downsview Ontario M3H5T4
Canada

Tel: 416-739-4330
Fax: 416-739-4380

Gerry Finfinger

U.8. Bureau of Mines
P.O. Box 18070
Cochrans Mill Road
Pittsburgh, PA 15236

Tel: 412-892-6550
Pax: 412-892-6614

Robert L. Frants

Asso. Dean for Continuing
Education

and Industry Programs

Penn State University

126 Mineral Sciences Building
University Park, PA 16803

Tel: 814-865-7471
Fax: 814-865-3248

David Friedman

Interstate Natural Gas Asso.
of America

555 13th Bt., NW
Washington, DC 20004

Tel: 202-626-3234
Pax: 202-626-3239

Page €-13



United States Air and EPA/400/9-90/007
Environmental Protection Radiation September 1990
Agency (ANR-445)

SEPA Methane Emissions and
Opportunities for Control

& Printed on Recycled Paper



Ken DeMoyse

Utah State University
Biometeorolgy Department
Box 785

Hyde Park, UT 84318
USA.

John Duxbury

Cornell University

Dept. of Agronomy, Bradfield Hall
Ithaca, NY 14853

USA.

Phone: 607-255-1732

Gary Evans

U.S. Department of Agriculture
Science and Education

Room 217 W

Washington, D.C. 20250

Phone: 202-447-5035

Fax: 202-755-7842

Paul Faeth

World Resources Institute

1709 New York Ave, NW
Washington, D.C. 20006
USA.

Phone: 202-662-3499

Fax 202-638-0036

Telex. 64414 WRIWASH US

David Foster

Science and Policy Associates
1333 H Street, NW

The Landmark Building, Suite 400
Washington, D.C. 20005

USA.

Phone: 202-789-1201

Fax —- 202-789-1206

Robert Frye

Senior Research Scientist
Environmental Research Lab
University of Arizona
ERL-2601 East Airport Drive
Tuscon, AZ 85706

USA.

Phone: 602-741-1990

Leslie Gallo

Science and Policy Associates
1333 H Street, NW

The Landmark Building, Suite 400
Washington, D.C. 20005

USA.

Phone: 202-789-1201

Fax: 202-789-1206

Michael Gibbs

ICF Consulting Associates, Incorporated
10 Universal City Plaza

Suite 2400

Universal City, CA 91608-1097

USA.

Phone: 818-509-7150

Fax. 818-509-3925

Thomas J. Goreau

United Nations

Center for Science and Technology Development
324 North Bedford Road

Chappaqua, NY 10514

USA.

Phone: 914-238-8788

Peter Groffman

University of Rhode Island

Department of Natural Resources Science
Kingston, RI 02881

USA.

Phone: 401-792-2902

Fax 401-792-4017

Thurman Grove

US. Agency for International Development
S$ & T/AGR

Room 403 SA-18

Washington, D.C. 20523

USA.

Phone: 703-875-4045

Fax 703-875-4384

Tesfaye Haile

Training and Research Services

National Meteorological Services Agency
Box 1090

Addis Ababa

ETHIOPIA

Phone: 251-1-512-299 ext. 256

Telex, 21474 TMET ET

Page E-3



- surface water infiltration;
-- groundwater infiltration;
-- water released during decomposition; and

-- liquid additions to the landfill (e.g., sludge,
septic tank pumpings, leachate recirculation).

Refuse is normally 20 to 30 percent water by weight
(Pacey and DeGier, 1986; Noble et al., 1988). There is
disagreement in the literature as to what moisture
content leads to optimal CH, generation. For example,
Pacey and DeGier (1986) indicate 40 to 45 percent (by
weight) as the optimal value. cChian and Dewalle (1979)
state that maximum gas production occurs when the
moisture content is 75 percent or greater, while
Pohland and Harper (1986) suggest that increasing the
moisture content above 60 percent results in no change
in CH, production. Researchers do agree, however, that
decomposition is optimized when water is distributed
evenly throughout the landfill. The formation of "wet"
and "dry" regions within the landfill, a phenomenon
that is likely to occur when the refuse is baled prior
to disposal, can limit overall CH, generation.

Temperature. Because anaerobic digestion is an
exothermic process, landfill temperatures tend to be
higher than ambient air temperatures. The extent to
which ambient air temperatures influence CH, generation
rates depends mainly on the depth of the landfill. In
shallow landfills, microbial activity may be responsive
to ambient air temperatures; CH, generation is greatly
reduced when temperatures are below 10°C to 15°C (Pacey
and DeGier, 1986). In deeper landfills, however,
ambient air temperature effects are less significant.

A self-regulating average landfill temperature of 35°C
within the anaerobic zone can be expected (Gunnerson
and Stuckey, 1986).

pH and Buffer Capacity. Landfill cH, generation is
greatest when near neutral pH conditions exist within a
landfill. A pH range of 6.8 to 7.2 is considered
ideal, but CH, production takes place in pH
environments ranging from 6.5 to 8.0 (Pacey and DeGier,
1986). In acidic environments (i.e., pH below 6.0),
the activity of methanogenic bacteria is inhibited.
Although landfills are typically acidic when wastes are
first buried, the pH usually reaches near-neutral
conditions within the first or second year after
placement. This is largely due to the buffering

Page C-4



Key national and international authoritative bodies
should cooperate in identifying and evaluating the best
techniques for reducing CH, emissions from livestock
systems.

Potential CH, emissions reductions associated with
modifications to eating habits of humans are beyond the
scope of the meeting, and is primarily a question of
social choice and human nutrition and health needs.

62



Animal Wastes. Technologies and practices exist that
can reduce methane emissions by 50 to 80 percent from
animal waste management systems that are used for large
numbers of confined animals. These approaches
primarily involve anaerobic treatment (e.g., in a
lagoon) with methane recovery and utilization. These
approaches appear to be cost effective in many
circumstances, due to the value of the energy produced.
To promote the reduction of methane emissions from
animal wastes, the following are required:

° The best waste management practices for reducing
methane emissions that are consistent with other
environmental objectives, including groundwater
protection, water management, and nutrient
Management, need to be defined.

. Approaches for reducing methane emissions need to
be demonstrated under a wider range of conditions
than has been demonstrated to date.

. To improve the existing approaches, further work
is needed to identify and demonstrate gas
utilization opportunities in the agricultural
setting.

4. Policy Options for Reducing Methane Emissions from Waste
Management Systems

4.1

Market and institutional barriers exist that limit the
implementation of cost-effective technologies and
practices that will reduce methane emissions from waste
Management facilities. These barriers should be
identified and evaluated. Approaches, including
financial incentives, should be identified to overcome
these barriers.

° A lack of financing and the unavailability of some
technologies are important barriers that must be
overcome in some areas.

. In the design of incentives to overcome identified
barriers, the incentives should reflect the
environmental benefits that will accrue from the
implementation of the technologies and practices.

48



EXHIBIT B-3

METHANE EMISSIONS FROM COMBUSTION SOURCES

Emission Source Emissions Factor Source
(grams CH, per GJ)

Mobile Sources:

Gasoline 130 Unnasch and Moyer
Diesel 20 Unnasch and Moyer
Gasoline’ 36 - 60 Radian

Diesel 2- 8 Radian

Jet Aircraft 2 Radian

Rail Engines 13 Radian

Ships 20 Radian
Stationary

Sources:

Natural Gas Boiler 0.5 Radian

Coal Boiler 0.3 Radian

Oil Boiler 2 Radian

Wood Stoves 70 Radian

Represents uncontrolled sources (e.g., automobiles without
catalytic converters) .

Sources:

Radian Corporation (1987), "Emissions and Cost Estimates for
Globally Significant Anthropogenic Combustion Sources of NO,,
CH,, CO and CO,," Prepared for the U.S. EPA.

Unnasch, S. and C.B. Moyer (1989), "Comparing the Impact of
Different Transportation Fuels on the Greenhouse Effect,"
prepared for the California Energy Commission by Acurex
Corporation, March 1989.

Page 8-15



Exhibit 8: Global Warming Potential of
Methane as a Function of Time Over
Which Warming is Compared.

Global Warming Potential

120

100

80

of Methane

D

© This Workshop
5 IPCC (WG1)

T T T 1
0 200 400 600 800 1000

uration (years) over which warming caused is
compared to that caused by carbon dioxide.



emissions reduction is consistent with the estimates derived
above based on the known rate of increase of methane in the
atmosphere.

Similar results are seen in Exhibit 6 for the SCW scenario.
In this scenario emissions must again be reduced by about 30 Tg
to achieve stabilization in the near term. Exhibit 7 displays
the estimates of methane concentrations using these emissions.
The uncontrolled RCW and SCW scenarios show increasing methane
concentrations over time with concentrations increasing by 2100
to about 4,200 ppbv and 3,200 ppbv, respectively. The
concentrations are stabilized at about 1,700 ppbv by reducing
emissions in the near term, and then restraining growth in the
longer tern.

This analysis with the ASF indicates that methane
stabilization can be achieved and maintained with fairly modest
reductions in emissions in the near term and restraints on
emissions growth in the long-term. Over the next 30 years this
requires that methane emissions be reduced by about 30 Tg by the
year 2000, and that subsequent growth in emissions be restrained
to under 3 percent per decade in the following 25 years.
Furthermore, by limiting emissions growth over the long-term to
about 2 to 3 percent per decade, stabilization may be maintained
for longer periods of time. This range for the estimates of
reductions necessary to stabilize concentrations is fairly robust
across the wide range of potential future emissions of other
greenhouse gases that is examined.

Despite the various uncertainties in the overall estimate of
global methane emissions, it is clear that relatively small
reductions in emissions can be expected to halt the increase in
methane concentrations. The comprehensive observational record
on atmospheric methane concentrations provides confidence in the
level of emissions reduction that needs to be achieved, and
methane's relatively short lifetime helps to ensure that the
effects of emissions reductions will be observed quickly. These
elements indicate that stabilization of atmospheric methane
concentrations is feasible in the near-tern.'

"the ability to stabilize methane concentrations could be
undermined by other changes in emissions and atmospheric
composition, for example associated with increases in methane
emissions from natural sources or changes in the atmospheric
lifetime of methane. Although the ability to achieve
stabilization of atmospheric methane may be jeopardized in these
circumstances, the value of methane emissions reductions would
actually increase as a result of these changes.

18



Landfill gas, which is composed mainly of CH, and carbon
dioxide (CO,), results from the anaerobic decomposition of
organic degradable wastes which begins after the waste has been
in the landfill for a period of 10 to 50 days (Van Heuit, 1986).
While the rate of CH, production varies over the first 180 to 500
days (Van Heuit, 1986), eventually an equilibrium is achieved
within the landfill and steady state CH, generation occurs. Most
of the CH, generated in a landfill is produced during this steady
state phase. Although the majority of CH, generation typically
takes place within 20 years of landfill completion, it can
continue for 100 years or more. At this point transition occurs
from anaerobic back to aerobic conditions as the supply of
degradable organic material is depleted and air infiltrates the
landfill.

Additional work is necessary to obtain better estimates of
CH, emissions and to better understand the effects of a number of
important site-specific factors. These include

. Was Composition. Probably the most important factor
affecting CH, generation rates and quantities is the
composition Of the landfilled waste. The waste
represents the "raw material" for CH, generation, as it
provides degradable organic materials and nutrients for
the system. The presence of certain constituents in
the refuse could inhibit CH, production, such as heavy
metals or other toxic substances that retard bacterial
growth (Pacey and DeGier, 1986). In addition,
different types of wastes are known to decay at
different rates, although the actual rates depend on
site-specific conditions. Food wastes, for example,
are considered readily biodegradable, while paper
wastes degrade at a more moderate rate. Textiles and
the lignin fraction of wood are considered slowly
biodegradable (Wilson et al., 1988; Gunnerson and
Stuckey, 1986).

. Moisture Content. The amount of moisture within a
landfill is another important factor affecting gas
generation rates, as an aqueous environment is required
for anaerobic degradation of waste. Not only do
methanogenic bacteria perform better as the moisture
content increases, but water acts as a transport medium
that carries nutrients and bacteria throughout the
landfill while moving intermediates away from the
bacteria-substrate interface. Several factors affect
the moisture content of landfills:

-- moisture content of the waste at the time of
disposal;



Don schellhardt
American Gas Association
1515 Wilson Boulevard
Arlington, VA 22209

Tel: 703-841-8464
Pax: 703-841-8406

Jeff Schwoebel
Resource Enterprises, Inc
400 Wakara Way
Salt Lake City, UT 84108

Tel: 801-584-2436
Pax: 801-584-2424

Dr. Horst Selzer

Ludgwig Bolkow System Technik
GmbH

Dimlerstr. 15

D-8012 Ottobrun

West Germany

Tel: 089-60811026
Fax: 089-6099731

Paul Shapiro

Us EPA

RD-681

401 M Street, SW
Washington, DC 20460

Tel: 202-382-5747
Fax: 202-245-3861

Toufiq A. Siddiqi
Environment and Poalicy
Institute

East-West Center

1777, East-West Rd.
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Tel: 808-944-7233
Pax: 808-944-7970
Telex: 230-989-171

Hema J. Siriwardane
Professor, West Virginia
University

College of Engineering

637 Engineering Science Bldg.
wvu

Morgantown, WV 26506

Tel: 304-293-3192

Fred A. Skidmore, Jr.
Controlled stimulation &
Production, Inc.

3604 Wentwood

Dallas, Texas 75225

Tel: 214-361-4704 or
214-720-9850

Lowell smith

U.8. EPA

RD-682

401 M Street, SW
Washington, DC 20460

Tel: 202-382-5717
Fax: 202-382-6370

Barry Ssolomon

Us EPA

401 M Street, SW

PM 221

Washington, DC 20460

Tel: 202-382-4334
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Dr. Lasslo Somos
Hungarian Geological Institute
1022 Bimbo U. 9619

Tel: 36-1-183 69 12
Telex: 225 220 Mafi h.

Page E-20



Hilmar von Schonfeldt
Island Creek Corporation
250 West Main street

PO Box 11430

Lexington, KY 40575

Tel: 606-288-3595

Hubert Wank

Canadian Gas Research
Institute

55 Scarsdale Road

Don Mills

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Tel: 416-447-6465
Fax: 416-447-7067

John W. Warner
Amoco Corp.

PO Box 3092

580 West Lake Blvd.
Houston, TX 77253

Tel: 713-556-4259
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Dr. Ian A. Webster
UNOCAL Corp.

1201 West Sth Street
Suite MK-35

Los Angeles, CA 90051

Tel: 213-977-6382
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D. J. Williams

CSIRO Div. Coal Technology
PO Box 136

MN. Ryde, NSW 2113
Australia

Tel: 61-2-887-8666
Pax: 61-2-887-8909
Telex: AA 25817

Jonathan Woo

ICP Consulting Associates,
Inc.

10 Universal city Plaza
Suite 2400

Universal City, CA 91608

Tel: 818-509-7157
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J. Remko Ybena

Netherlands Energy Research
Foundation

PO Box 1

1755 26 Petten

The Netherlands

Tel: 02246-4428
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Yuan Benhang

Head of Ventilating Dept.
K.M.A./

Senior Mining Engineer

Xinhua Zhongdao Tangshan Hebei
People’s Republic of China
Kailuan Mining
Adnininistration

Tel: Tangshan 23811-2129

Hung Zhu

IcP Resources
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Tel: 202-382-7750
Fax: 202-382-6344

0.8. Government Printing office + 1992 - 312-014/40066 Page E-23



4. FRAMEWORK FOR CONTROL

4.1 Approaches

A variety of approaches have been used to control pollution
emissions for purposes of achieving environmental protection
goals. In terms of international controls, the Montreal Protocol
on Substances that Deplete the Ozone Layer is currently the only
example in which the international community has limited air
emissions of a class of substances, in this case CFCs and halons.

The Montreal Protocol was signed in 1987 and has been
ratified by all the major CFC producing and consuming countries
of the world. Under the Protocol, each nation agrees to limit
its production and consumption of two separate groups of
compounds, CFCs and halons, to specific levels. The
participating nations are each free to achieve their production
and consumption limits in any manner that they prefer. Included
in this flexibility is the opportunity to trade off among the
CFCs or among the halon compounds at agreed on rates. For
example, 1 kilogram of CFC-11 may be traded off for 1 kilogram of
CFC-12 or 1.25 kilograms of CFC-113. However, trade offs between
CFCs and halons are not permitted.

In the U.S. and elsewhere, approaches for protecting the
environment have also included technology requirements, ambient
standards, and performance standards. Under these approaches
specific equipment or practices are identified as the preferred
method for preventing discharges of pollutants into the
environment, and steps must be undertaken to install the
identified equipment and implement the practices. Flexibility is
often provided that allows alternative equipment and practices to
be implemented that achieve the same performance in terms of
emissions reductions achieved.

The recently completed Basel Convention on the Control of
Transboundary Movements of Hazardous Wastes and Their Disposal is
an example of an international agreement that relies on
technology requirements to protect the environment. The purpose
of the Basel Convention, which was completed in 1989, is to
control the transboundary movement of hazardous wastes. To
achieve this objective, the convention establishes a system for
defining and tracking international movements of hazardous
wastes.

Additionally, the convention sets out a process whereby the
parties to the agreement will define the waste disposal
technologies and practices that are considered "environmentally

30



As an illustrative example, a high producing dairy cow
produces about,1000 kilograms of VS of wastes per year. Ata
rate of 0.25 m*> of methane per kilogram of VS, the potential
methane emissions from this waste is about 175 kilograms. This
level of emissions is about twice the methane anticipated to be
produced within the rumen of the same cow.

While the potential CH, emissions from animal wastes are
large, the realized emissions are likely to be much smaller. If
aerobic conditions exist (when the manure is in contact with
oxygen) then CH, production is minimal. If the manure is held
under anaerobic conditions (in the absence of oxygen), then the
manure can produce CH,.

Several of the systems used to manage animal wastes include
the following:

. Fertilizer. In many parts of the world, manure is used
as a fertilizer. If it is spread on dry soils and
decomposes aerobically, then little CH, production is
likely. If the manure is spread on anoxic soils (e.g.,
flooded rice paddies) then CH, production is likely.

. Fuel. Manure is dried and used as a fuel source.
Burning dried manure probably creates little CH, as the
organic material oxidizes directly to carbon dioxide
(measurements are required to confirm this expectation)
In other cases the manure is collected and used in a
biogas (i.e. CH,) generator where the organic material
in the manure is deliberately converted into CH,,
collected and burned as a fuel. CH, will only be
emitted to the extent that it leaks’ from the biogas
system or was incompletely burned.

. Waste Handling. In locations where large number of
animals are held in a confined area (dairies and
feedlots, swine and poultry facilities) animal waste
required proper handling and disposal. The waste may
be piled up until it can be hauled away or washed into
ponds for treatment. In either case anaerobic bacteria
exist, and some portion of the organic matter in the
wastes will be converted to CH,.

. Pasture and Range. Animals that are grazing on pasture
or ranges are not on any true waste handling system.

The wastes from these animals dry out and decompose.
Minimal amounts of CH, are expected from these wastes,
although measurements are lacking to quantify the CH,
releases.

Page C-13



° Emissions reduction: the extent to which emissions are

reduced.

. Impact on animal productivity: the manner in which
implementing the option would affect production of animal
products.

. Costs: the cost of implementing the option.

° Implementation: methods of implementing the option,
including any special challenges posed, such as social
constraints.

Some of the promising options for reducing emissions include:

trategic su) ementation of extensiv: mana .
Large numbers of cattle consume forages of variable quality,
particularly seasonally, under grazing conditions. These diets
may be deficient in certain vital nutrients (e.g. nitrogen) that
hinder animal productivity and reproductive efficiency.
Supplementing the diets of these animals (through range
enhancement or bolus) can reduce the amount of CH, produced by
providing a better balance in the rumen and by increasing the
efficiency and productivity of the animal (thereby reducing the
size of the animal population necessary to produce a given level
of products).

Diet modifications i nsivel. ni imals.
Experimental data from whole animal calorimetry experiments
demonstrate that CH, emissions vary under different diets. Both
increasing the intake of the animals and modifying the
composition of the diet can reduce CH, emissions per unit of
product produced (e.g., per kilogram Of meat produced). Other
feed inputs also appear to have promising impacts on CH,
emissions levels (e.g., whole cotton seeds or polyunsaturated
fats). Modifying feeding practices toward low-methane rations
could potentially reduce CH, emissions by large amounts in
certain circumstances.

s_to asi roduction per cow.
The use of bST or productivity enhancement agents reduces CH,
emissions per unit of product produced by increasing the
productivity of the animal. For example, bST would reduce CH,
emissions per amount of milk produced by:

. further diluting the maintenance requirements of individual
lactating cows (resulting in a 3 to 5 percent reduction in
CH, emissions per amount of milk produced); and

Page D-16



9. FINDINGS FOR LIVESTOCK

The following are the findings that were adopted by
consensus by those attending the workshop. These findings
indicate that there are promising opportunities for reducing
methane emissions from livestock management systems. Such
opportunities remain to be assessed and demonstrated in the
field. Undertaking such assessments and demonstrations is a
recognized priority.

1. GENERAL

1.1 Given the fact that methane (CH,) concentrations are
increasing globally and will affect global climate and
tropospheric air quality, it is recognized that
opportunities for reducing CH, emissions must be
identified, evaluated, and applied in order to reduce
global warming and increases in tropospheric ozone.

1.2 Given the diverse set of CH, emissions sources
globally, emissions reductions from any single country
or source will be small compared to total CH
emissions, and small compared to total emissions of all
greenhouse gases. Consequently, programs to reduce CH,
emissions from many sources will be required in many
countries.

1.3 Although emissions-reduction programs will be required
in many countries to achieve significant emissions
reductions, individual countries can make valuable
contributions by developing, demonstrating, and
implementing emissions-reduction technologies.

2. THE ROLE OF MANAGED LIVESTOCK IN THE GLOBAL METHANE BUDGET

2.1 Livestock, and in particular ruminants, are
comparatively an important source of CH, emissions on a
global scale.

2.2 Animals produce significant quantities of CH, as

part of their digestive processes. emissions
from the digestive processes of all sninels have

54



collection and diverting the waste to another process
may be an effective option for reducing CH, emissions.
For example, waste paper recovery can greatly reduce
the amount of organic waste being landfilled and the
collected paper can be used in secondary paper
products, biofuel facilities, or composted.

. Incineration. Waste incineration may be a very
effective pretreatment method for the reduction of CH,
from landfills because it can reduce total waste
volumes to be landfilled. However, waste incineration
is itself a source of greenhouse gas emissions in
addition to pollutants such as NO,. Use of
incineration as a CH, reduction technology requires
careful setup and monitoring of operating parameters
such as combustion temperature, air mixture, gas
residence time, secondary combustion chamber, and
appropriate methods for reducing air pollutants.

c.2 Wastewater Treatment

Wastewater treatment can produce CH, emissions if organic
constituents in the wastewater are treated anaerobically (i.e.,
under conditions in which no oxygen is present), and if the CH,
produced is released to the atmosphere. Wastewater treatment
plants in developed countries rely principally on aerobic
treatment, or anaerobic treatment in enclosed systems where the
CH, is recovered and utilized. Consequently, wastewater
treatment in most developed countries is not considered a major
source of CH, emissions.

In developing countries and at individual facilities in
developed countries wastewater treatment using anaerobic lagoons
is expected to produce large quantities of CH, emissions. At
facilities with high organic waste loads, a series of anaerobic
lagoons is often used to treat the wastewater. The organic waste
is converted by anaerobic bacteria to CH, and CO,, which are
released into the atmosphere.

Virtually no data are available with which to produce
precise estimates of these emissions. A rough estimate was made
using the following:

. The organic waste load in wastewater can be described
in terms of milligrams of biochemical oxygen demand per
liter (mg/l of BOD).

. Food processing facilities generally produce wastewater
with very high organic loadings, in the range of 30,000
to 100,000 mg/l of BOD. Food processing facilities

Page C-10



A recent study performed for EPA (ICF Resources (1990) )
indicates that CH, emissions from coal mining is on the
order of 50 Tg per year. The majority of these
emissions are estimated to be in five countries: the
United States; the People's Republic of China; the
Soviet Union; Poland; and South Africa. This study
also indicates that CH, emissions from coal mining can
increase substantially in the next 20 years as:

(1) increasing amounts of underground coal is mined;
and (2) the coal mined underground is withdrawn from
deeper and gassier coal seams.

Discussion at the IPCC Workshop included a wider range
of emissions estimates. The workshop participants
agreed that CH, emissions may be on the order of 30 to
50 Tg per year, with some estimates as low as 20 Tg per
year and some as high as 60 Tg per year.

Natural gas production and distribution and oil
production. Natural gas resources (which are mostly
CH,) are exploited around the world. During the
production, transmission, and distribution of this gas,
quantities may be released accidentally (e.g., during a
pipeline rupture or as the result of a slow leak) or
intentionally (e.g., during maintenance and repair of a
pipeline). When oil is produced, natural gas is also
often found and when gas production facilities are not
available, this gas may be vented to the atmosphere or
flared.

Total emissions from these sources are quite uncertain.
Recent estimates of emissions from natural gas
production and distribution systems have relied heavily
on estimates of "unaccounted for" gas, which is defined
as the difference between the total gas produced and
the total gas sold. The assumption underlying these
estimates is that all the unaccounted for amounts are
released to the atmosphere. Using this approach, these
emissions are on the order of 2 to 4 percent of total
gas production annually, or about 25 to 50 Tg.

Other factors that may account for unaccounted for gas
include theft and meter inaccuracies. A recent study
by Pacific Gas and Electric Company (PG&E (1989) )
indicates that emissions to the atmosphere may be a
very small portion of the total amount of gas that is
routinely referred to as unaccounted for. If the PG&E
analysis is correct, then actual emissions from this
source may be much smaller than recent estimates would

Page A-6



3. OPPORTUNITIES FOR EMISSION REDUCTION

Control of methane may be more feasible than once perceived.
Because scientists are unable to quantify emissions from each
source precisely, and because there is uncertainty regarding the
relative importance of past increases in emissions and increases
in methane's atmospheric lifetime in causing the observed
increase in concentrations, it has been frequently thought that
methane concentrations could not be controlled. However, this
logic fails to recognize that to stabilize methane concentrations
we do not need to know precisely the emissions from each source
nor the relative importance of past changes in emissions and
atmospheric lifetimes. To stabilize concentrations we only need
to know the amount by which emissions exceed destruction in the
atmosphere and how to reduce emissions.

As described earlier, the extent to which methane emissions
exceed methane destruction in the atmosphere can be estimated
from the observational record. These data indicate that reducing
anthropogenic emissions by about 10 percent will stabilize
atmospheric concentrations of methane. It is not necessary ‘to
characterize all the anthropogenic sources of emissions precisely
nor to estimate all their growth rates. It is only important
that an adequate level of emissions reductions are achieved from
some combination of sources. It will be most cost effective to
undertake the least costly opportunities for reducing emissions,
as opposed to reducing emissions from all sources of from the
fastest growing source. As discussed at the IPCC workshops, many
options for reducing methane emissions have low costs, or may
even be profitable because methane is actually lost energy, and
systems may be redesigned to capture and use this energy in many
cases.

Opportunities for reducing methane emissions from its major
anthropogenic sources will need to be identified as no one source
can provide the reductions required to stabilize atmospheric
concentrations. The IPCC workshops identified a set of promising
approaches for reducing emissions. These emissions reduction
opportunities include:

. Landfills: Methane recovery systems can reduce
emissions by 30 to 60 percent in existing landfills and

2 programs may also be necessary to limit emissions of

pollutants such as carbon monoxide which compete with methane for
the hydroxyl ion in the atmosphere. While these pollutants may
hinder the stabilization of methane concentrations, the
reductions in methane concentrations that are achieved will still
have benefits in terms of limiting warming.

24



. Replace venting with flaring of natural gas. Natural
gas can be vented or flared during the withdrawal and
field separation of oil and gas at production
facilities. CH, emissions can be reduced by replacing
venting systems with flares and by improving the
combustion efficiency in flares.

. Replace cast iron pipes. Cast iron pipes leak far
larger amounts of natural gas than most other types of
pipes. Replacing these pipes or repairing the leaks
(by sealing the pipe joints) will significantly reduce
CH, emissions from this source.

. Increase odorant concentrations. Mercaptan is added to
natural gas to give it a distinctive odor. By
increasing the concentration of mercaptan, leaks will
be detected sooner. In Japan, the mercaptan
concentration is typically ten times greater than the
concentration in most U.S. natural gas systems.

Natural gas leakage is consequently expected to be much
lower in Japan.

. Install "smart" residential meters. Smart meters
detect unusual natural gas usage patterns (caused by a
leak for example) and shut off the supply. These
meters are being installed in Japan and are expected to
reduce residential leakage of natural gas.

It also was suggested that abandoned oil and gas wells may
emit significant quantities of CH, to the atmosphere. In
addition, the leaky casings in producing oil and natural gas
wells may allow significant quantities of CH, to be emitted to
the atmosphere.

B.2 Coal Mines
Emissions

Coal mining is a significant source of CH, emissions. CH,
is found to occur naturally in coal seams, having been formed
while the coal itself was formed. When coal is mined from
underground seams, CH, is released. The amounts released vary by
the type of coal and the depth of the coal seam. CH, may also be
released when shallow deposits are mined (i.e., surface-mined
coal), although these quantities may be relatively low.

Recent estimates indicate that approximately 50 Tg of CH,,
or about 10 percent of the total CH, budget, are released into
the atmosphere annually as a result’ of coal mining and processing

Page B-8



1. INTRODUCTION

This report compiles the work that has been performed on
emissions of methane (CH,) from anthropogenic sources and options
for reducing these emissions by two subgroups of the Intergovern-
mental Panel on Climate Change (IPCC) Response Strategies Working
Group:

. Agriculture, Forestry, and Other Human Activities
Subgroup (AFOS) and

° Energy and Industry Subgroup (EIS).

Two international workshops held in support of the IPCC
process provided the information for this report. The first
workshop, held on December 12-14, 1989, by the U.S. Environmental
Protection Agency and the U.S. Department of Agriculture examined
greenhouse gas emissions from agriculture in support of AFOS.
This workshop examined emissions of methane from livestock
systems and rice cultivation, among other agricultural sources of
emissions. The second workshop was held on April 9-13, 1990.
Funded jointly by the Environment Agency of Japan, the U.S.
Environmental Protection Agency and the U.S. Agency for
International Development, this workshop examined methane
emissions from natural gas systems, coal mining activities, and
waste management.

This report summarizes and synthesizes the analyses
presented at these workshops in the following manner. Chapter 1
provides an overview of the report. Chapter 2 discusses
methane's contribution to global warming. This chapter also
summarizes the data that show that atmospheric methane
concentrations are increasing and the contribution that these
increases are making to global climate change. This chapter
estimates the emissions reductions that are needed to stabilize
atmospheric methane concentrations. Finally, the unique near-
term benefits of controlling methane emissions are discussed.

Chapter 3 summarizes the information presented at the
workshops on the manner in which methane emissions can be reduced
from its primary anthropogenic sources. The information
presented in this section indicates that the emissions reduction
techniques discussed at the workshops are adequate to stabilize
atmospheric methane concentrations at approximately current
levels.

Next, Chapter 4 discusses issues involved in designing a
framework for controlling methane emissions internationally. The

5



indicate. Engineering analyses performed for EPA (PSI
(1990)) also indicate that these emissions may be
smaller than had previously been anticipated.

CH, emissions from venting and flaring of gas during

4 production are also not well characterized.
Marland and Rotty (1984) estimate total amounts of gas
that are flared and vented. Cicerone and Oremland
estimate total CH, emissions from vented and flared
gas, plus "other stray and explosive losses" to be
about 14 Tg per year.

Fuel Combustion and Biomass Burning. Many combustion

processes emit hydrocarbons, including CH,. For
example, CH, is found in automobile exhaust, and has
been estimated to be found at quantities on the order
of 170 ppmv (Campbell (1986)). Combustion of fossil
fuels in mobile and stationary sources is consequently
a source of CH, emissions, although preliminary
estimates indicate that the emissions are small (less
than 10 Tg per year).

In analyses of overall CH, emissions, CH, emissions
from biomass burning (i.e., forest clearing and
agricultural waste burning) have been studied.

Cicerone and Oremland indicate that such estimates are
very uncertain and that additional measurements are
required. Based on analyses by Seiler (1984) and
Crutzen (1987), Cicerone and Oremland report a range of
50 to 100 Tg per year for this source, with a central
estimate of 55 Tg.

Landfills. The decay of organic wastes in landfills
and dumps is known to produce CH, gas. In the U.S.,
such gas (when uncontrolled) has been the source of
problems at landfills. Consequently, in many
locations, such cH, gas is either vented, flared, or
recovered as an energy source. Bingemer and Crutzen
(1987) estimate total emissions from this source to be
30 to 70 Tg per year.

The factors that lead to _CH, production in landfills
and the subsequent emission of that CH, have been
studied extensively. At the IPCC Workshop the range of
CH, emission estimates presented was 25 to 40 Tg per
year. This lower range was developed because
landfilled waste does not seem to be decomposing as
quickly as the assumptions in the earlier estimates
reflect.

Page A-7



Blaxter, K.L. and J.L. Clapperton (1965), "Prediction of the
Amount of Methane Produced by Ruminants," British Journal of
Nutrition, Vol. 19, pp. 511-522.

Bolle, H.-d., W. Seiler and B. Bolin (1986), "Other Greenhouse
Gases and Aerosols: Assessing Their Role for Atmospheric
Radiative Transfer." In: Bolin, B., B.R. Doos, B. Warrick and
D. Jager (eds.), The Greenhouse Effect Climatic Change and
Ecosystems, New York, John Wiley & Sons, pp. 157-203.

Campbell, I.M. (1986), Energy and the Atmosphere, John Wiley &

Sons Ltd., New York, New York, 2TM Edition.

Casada, M.E. and L.M. Safley, Jr. (1990), "Global Methane
Emissions from Livestock and Poultry Manure," presented at the
International Workshop on Methane Emissions, April 9-13, 1990,
Washington, D.C., sponsored by the Environment Agency of Japan
and the U.S. Environmental Protection Agency.

Cicerone, R.J. and R.S. Oremland (1988), "Biogeochemical Aspects
of Atmospheric Methane," Global Biogeochemical Cycles, Vol. 2,
No. 4, 299-327, December 1988.

Cicerone, R.J., J.D. Shetter, and C.C. Delwiche (1983), "Seasonal
Variation of Methane Flux From a California Rice Paddy," Journal
of Geophysical Research, Vol. 88, pp. 11022-11024.

Cicerone, Ralph J. and J.D. Shetter (1981), "Sources of
Atmospheric Methane: Measurements in Rice Paddies and a
Discussion," Journal of Geophysical Research, Vol. 86, pp. 7203-
7209.

Crutzen, Paul J., I. Aselmann and W. Seiler (1986), "Methane
Production by Domestic Animals, Wild Ruminants, Other Herbivorous
Fauna, and Humans," Tellus, 38B, pp. 271-284.

Crutzen, P.J. (1987), "Role of the Tropics in Atmospheric

Chemistry." In: Dickinson, R. (ed.), Geophysiology of Amazonia,
New York, Wiley & Sons, pp. 107-132.

Ehhalt, D.H. (1974), "The Atmospheric Cycle of Methane," Tellus,
Vol. 26, pp. 58-70.

Harriss, R.C., E. Gorham, D.I. Sebacher, K.B. Bartlett, and P.A.
Flebbe (1985), "Methane Flux from Northern Peatlands," Nature,
Vol. 315, p. 652-654.

Holzapfel-Pschorn, A. and W. Seiler (1986), "Methane Emission
During a Cultivation Period From an Italian Rice Paddy," Journal

of Geophysical Research, 91, pp. 11803-11814.

Page A-13



FINDINGS

Two international workshops held in support of the
Intergovernmental Panel on Climate Change (IPCC) provided
information on current methane emissions and opportunities for
reducing these emissions. The first workshop, held on December
12-14, 1989, by the U.S. Environmental Protection Agency and the
U.S. Department of Agriculture, examined greenhouse gas emissions
from agriculture in support of the Agriculture, Forestry, and
Other Human Activities Subgroup (AFOS) of the Response Strategies
Working Group.

The second workshop was held on April 9-13, 1990. Funded
jointly by the Environment Agency of Japan, the U.S.
Environmental Protection Agency and the U.S. Agency for
International Development, this workshop examined methane
emissions from natural gas systems, coal mining activities, and
waste management in support of the Energy and Industry Subgroup
(EIS) of the Response Strategies Working Group.

The information presented at these two workshops provided
the information compiled in this summary report. Based on the
synthesis of the information presented at the workshops, the
following findings are identified.

1. Atmospheric levels of methane are increasing and will affect
tropospheric air quality and global climate change.

1.1 Methane is an important greenhouse gas that, based on
model calculations, accounts for about 15 percent of
the current increase in commitment to global warming.

1.2 The global average methane concentration is currently
increasing by about 1 percent per year. This rate of
increase is well characterized for the recent past. In
addition, ice core data show that methane
concentrations have more than doubled in the last two
centuries and that they are now substantially higher
than they have been in the past 160,000 years.

' his statement is adopted from the IPCC Workgroup 1

Science Assessment Report. The group discussion at the AFOS
workshop attributed about 20 percent of the recent increase in
radiative forcing to methane based on the work of Hansen et al.
(1988).



. developing strategies that combine gas enhancement and
other landfill practices with increased collection
system efficiency;

° identifying techniques to encourage more widespread use
of recovery systems;

. developing techniques for enhancing methane generation
in cases where the methane can be captured and
utilized;

° developing cost beneficial uses of recovered methane

from landfills (particularly small landfills), such as
lower cost electricity generation technologies.

These advancements would allow the identification of best
control/recovery/utilization technologies and practices that are
appropriate for various landfill situations, including new versus
existing landfills.

CH, emissions from landfills may also be reduced by reducing
the amount of municipal solid waste generated and disposed in
landfills. For example, roughly 80 percent of the municipal
solid waste generated each year in the United States is currently
landfilled. Although a majority of municipal waste can be
expected to be landfilled in the future, a considerable effort to
find alternatives to landfilling is currently taking place
because of a variety of environmental concerns such as surface
water contamination, leaching of contaminants into ground water,
increased regulation, and increased costs of landfilling (the
average charge to dispose a ton of waste in the United States
increased from $11 in 1982 to $29 in 1988 (Pettit, 1989)).
Current efforts are examining the potential for waste reduction,
recycling and incineration techniques for management of solid
waste.

It is necessary to examine the effect of alternative waste
management and treatment programs on emissions of methane and
other greenhouse gases, including: waste stream separation and
recycling; and incineration with energy recovery. The individual
options are as follow:

. Waste Reduction. Reduction of the total waste volume
is the first step toward reducing CH, emissions from
waste management. This could first be accomplished by
eliminating wasteful use of resources in living and
business activities.

. Recycling. Because it is the organic portion of
disposed waste that generates CH,, sorting waste during

Page C-9



their increasing levels of activities, CH, emissions have
probably increased over the last 200 years from: rice
cultivation, animal husbandry, coal mining, waste management, and
oil and gas production, distribution, and use. Reductions in the
rate at which CH, is destroyed in the atmosphere may also be
playing a role. However, it is important to understand that
regardless of the role played by changes in the rate of
destruction of CH, in the atmosphere, reductions in emissions
will be effective’ in reducing the rate of increase of CH,
concentrations and stabilizing or further reducing its
concentration.

A.3 Emissions Reduction Opportunities

Initial assessments of these CH, sources have identified
cost-effective or low cost techniques for reducing emissions.
Preliminary results are as follow:

. Coal Mining. CH, from coal mining is often pipeline
quality and can be recovered as a resource. It is
likely that up to 50 percent of CH, emissions can be
reduced through pre-mining degasification at gaseous
mines in the primary coal producing countries.

. Landfills. CH, recovery at landfills is becoming
recognized as cost effective at many locations and
techniques to enhance CH, generation and recovery are
being continually refined. CH, recovery can reduce CH,
emissions by 30 to 90 percent, the recovery percentage
dependent upon site-specific factors. Recovery will
occur at U.S. landfills in response to air emission
regulations from landfills to be promulgated over the
next year or two.

. Livestock. Livestock generate a large portion of
annual CH, emissions (80 Tg/yr). Through changes in
diet and 4nimal management, emissions may be reduced by
25 to 75 percent per unit of product.

. Animal Wastes and Wastewater treatment. Recovery of
CH, from anaerobic waste treatment lagoons is cost
effective at sites with large concentrations of animals
(such as feedlots and dairies) and highly concentrated
waste streams (such as food processing plants).

. Rice. Recent work shows that CH, emissions may be
reduced by decreasing use of animal manures as
fertilizer. Recently experts agreed that CH, emissions
could likely be reduced by 10 to 30 percent by an

Page A-t1



effects of liquid within the landfill. Studies have
shown that the addition of buffering agents can enhance
CH, production (Pohland, 1986), although others argue
that the results of adding buffers are inconclusive.

Nutrients. Certain nutrients are necessary for
anaerobic digestion to occur. These include carbon,
hydrogen, nitrogen, and phosphorus. Potassium, sodium,
magnesium, calcium, and sulfur also have a role in the
process. In general, municipal solid waste contains
the nutrients necessary to support methanogenesis.

Refuse Density and Particle Size. The particle size

and density of the waste also influence CH, generation,
as these factors affect the transport of nutrients and
moisture throughout the landfill (Noble et al., 1988).
Although there is some disagreement in the literature
on the exact effects of waste density, it is commonly
agreed that as density increases, gas generation also
increases (Pacey and DeGier, 1986). For example,
shredded refuse, which has a high density and a small
particle size, retains moisture better and creates a
larger surface area for bacterial activity than doés
non-shredded waste. Shredding may also release
microbes from the waste and increase the mass transfer
of nutrients. However, increased compaction of the
waste may decrease liquid mobility, thereby hindering
gas production.

These factors act in combination to define the gas
generation capacity and the gas generation rate constant for a

landfill.

Scientists have used a variety of methods to estimate

the gas generation capacity and have produced a range of values
as indicated below in a list compiled by Ham and Barlaz (1987):

8.2 ft? of gas per pound of refuse - theoretical
maximum, calculated stoichiometrically based on typical
composition of U.S. municipal refuse;

1.6 to 4.7 £t?/1lb - theoretical estimate based on
degradability of typical waste;

3.3 to 4.1 £t3/1b - laboratory measurement, anaerobic
digestion of refuse with sewage sludge; considered the
best that could be achieved in a landfill;

0.008 to 0.63 ft/lb - lysimeters or closed containers;
considered to underestimate the amount of CH, generated
in landfills;

Page C-5



EXHIBIT B~-2

METHANE EMISSIONS FROM THE
NATURAL GAS SYSTEM IN THE U.8.
(10” grams)

Normal Routine Upsets

Operations Maintenance and Mishaps Total
Withdrawal and
Field Separation 117 <1 1,000 1,117

L.
Gathering, |
Processing, 948 551 96 1,595
Transmission
Distribution 374 5 47 426
Total 1,439 556 1,143 3,138

Source: PSI (1989), “Annual Methane Emissian Estimate of the Natural Gas and
Petroleum Systems in the United States," prepared for the U.S. EPA by Pipeline Systems
Incorporated.



cattle wastes are likely to be of the same magnitude as
the CH, emissions from the cattle digestive processes.
Animal’ wastes under aerobic conditions do not produce
CH, emissions. Additional analyses should be performed
over the next year to quantify the magnitude of CH,
emissions from animal wastes. Preliminary analyses
indicate that emissions from this source may be on the
order of 15 Tg/year globally, or about 20 percent of
the CH, emissions from the digestive processes of
animals.

Reductions in CH, emissions from animals will assist in
reducing the rate of CH, increases, and may be one
important component in attempts to stabilize
atmospheric CH, concentrations.

EMISSIONS REDUCTION OPPORTUNITIES

3.1

While many uncertainties exist, it appears that there
are a number of technologies that can likely reduce CH,
emissions from livestock systems by 25 to 75 percent
per unit of product.

Total reductions achievable depend on how effectively
available interventions are deployed, and whether
interventions lead to increases in consumption of
livestock products.

Emerging and available technologies for reducing CH,
emissions from livestock systems should be widely
tested under applicable field conditions as soon as is
practical. With adequate resources these tests would
identify the best technologies and practices that could
be implemented where appropriate.

Promising avenues of investigation have been identified
that could result in additional opportunities for
reducing CH, emissions from livestock systems.

Better estimates of CH, emissions will allow targeting
of cost effective interventions to reduce emissions.
The emissions reductions achievable with the best
technologies will vary within and among countries with
variations in animal, management, and feeding
characteristics.

Animal production research that aims at increasing
efficiency of animal production will have considerable
impact on CH, emissions. This research must be
stimulated in all countries with large livestock
populations.

56



3.4 These reductions should be obtained while maintaining
the productivity of the rice fields in all instances.

A comprehensive approach including management of water
regimes, development of cultivars, efficient use of
fertilizers, and other management practices can be
postulated to achieve the proposed reduction in methane
emissions. However, current understanding of the complex
interaction between methane production and oxidation, as
well as on the exchange of methane between the atmosphere
and rice fields, is insufficient. This understanding is a
prerequisite for determining potential options on reduction
of methane emission rates. In the long-term a 10-30%
reduction may be possible if a comprehensive research
approach is developing the required technologies.

4.1 Better understanding of processes contributing to the
methane emissions from rice fields can only be achieved
by integrated, interdisciplinary projects which will
focus on studies of process related factors and which
will allow valid extrapolations.

Research is needed on:
. Biogeochemistry of methanogenesis in flooded rice
fields
-- methane production
-- methane oxidation
- factors regulating methanogenesis
. Methane fluxes from flooded rice fields
-- effect of climatic factors
-- effect of soil and water factors
-- effect of cultivars
-- effect of organic and chemical fertilizer
-- effect of cultural practices
-- site, seasonal and diurnal variation
-- relationship with other greenhouse gases
(e.g., nitrous oxide)

Research is necessary to develop field level
measurement techniques to assess spatial variability.
Simulation models are needed to synthesize the process
and field level data and to assess regional and global
impacts.

4.2 Since preliminary studies show that methods which
reduce emissions of methane could increase emissions of
nitrous oxide, these interactions should be
investigated. In particular, measurements of nitrous
oxide emissions in alternately wet and dry soils (rain-
fed rice ecosystems) are needed.

52



As shown in Exhibit 2, Blake and Rowland estimate that the
global average methane level in the atmosphere is increasing at
an annual rate of about 1 percent (16 ppbv). This estimate is
based on measurements of methane levels in "clean air" areas.
Consequently, the estimates are not influenced by potential
trends in local methane sources, and are representative of trends
in the overall global methane abundance.

Steele et al. (1987) report the results of two years of
weekly sampling at 23 locations around the globe. These data
provide the most detailed picture of the distribution of
atmospheric methane across all latitudes, and its seasonal
changes. The results of this detailed two-year assessment
included that methane levels were found to be increasing wherever
sufficiently long records were available. Steele et al. reported
an annual average global increase of 0.8 to 1 percent for the
period 1983 to 1985. They also reported evidence that the rate
of increase may have slowed in the Antarctic region, while no
evidence of a slowing was reported at other southern or northern
hemispheric locations.

In addition to the recent detailed analyses of atmospheric
methane that show recent and ongoing increases in abundance, a
series of ice core studies indicate that methane levels have been
increasing for about 200 to 300 years, and that levels were
fairly constant for the previous 700 to 2,700 years.
Additionally, analyses of solar spectra provide estimates of
rates of methane increases since 1961 that are consistent with
the ice core and recent observational data (Rinsland et al,
1985). Based on these analyses, it is well established that the
concentration of methane has more than doubled in the last 300
years and continues to increase today.

7 For example, if ambient measurements were taken over time

near an area where methane emissions were increasing (e.g., near
a coal mine that was being developed for the first time), then
increasing concentrations shown in the measurements could be
associated with the new source that is near where the air samples
were taken. In such a hypothetical case, the air samples would
be affected by a local source. The analyses that indicate that
global methane levels are increasing were performed in remote
locations to ensure that local sources do not influence the
measurements. Additionally, diverse locations measured around
the world all indicate an increase in methane levels; further
supporting the claim that methane levels are increasing globally.

® careful analyses of methane in ice cores indicates that
the increase in the last 200 to 300 years is not an artifact of
the analysis methods or the reaction of methane in the ice.
Ongoing studies are developing more precise relationships between
levels of methane in the atmosphere and in the ice.

14



7. FINDINGS FOR WASTE MANAGEMENT SYSTEMS

1. Emissions Estimates

1.1 There are currently large uncertainties in estimates of
methane emissions from waste management systems,
including landfills, animal waste management systems,
and wastewater treatment lagoons.

1.2 Despite these uncertainties, waste management systems
appear to be significant anthropogenic sources of
methane emissions.

° Landfills emit an estimated 25 to 40 million
metric tons of methane globally each year. This
methane is produced by the anaerobic decomposition
of wastes in the landfills. Although landfill gas
monitoring and other detailed landfill analyses
have been performed in various countries, global
methane emissions from landfills are uncertain
because the factors driving the level of methane
emissions are highly site specific, including:
the waste composition; the extent and rate of
waste decomposition; the pathways of methane
transport out of the landfill; and the extent of
methane oxidation prior to release from the
landfill.

. Preliminary analysis and limited monitoring
indicate that anaerobic wastewater treatment
lagoons that treat wastewater with high BOD
(biochemical oxygen demand) loading can produce
large amounts of methane emissions. Global
emissions from wastewater treatment lagoons may be
on the order of 20 to 25 million metric tons each
year. This estimate of global methane emissions
is very uncertain due to a lack of data on the
amount and type of wastewater treated in anaerobic
lagoons.

° Preliminary analysis and limited monitoring
indicate that animal wastes emit about 30 to 40
million metric tons of methane each year. Wastes
managed under anaerobic conditions as part of
confined animal management systems are the major
source of these emissions. This estimate of
global methane emissions is uncertain due to a
lack of data on the amount of wastes managed under

43



provide other significant environmental and safety
benefits. Additionally, when utilized as an energy
source, the methane recovered from landfills to reduce
emissions may displace more carbon intensive fuels,
thereby also reducing carbon dioxide emissions. To
promote the reduction of methane emissions from
landfills, analyses of existing technologies and
practices would be useful, including:

. Defining the best control/recovery/utilization
technologies and practices that are appropriate
for various landfill situations, including new
versus existing landfills.

. Examining the effect of alternative waste
management and treatment programs on emissions of
methane and other greenhouse gases, including:
waste stream separation and recycling; and
incineration with energy recovery.

To improve the currently available technologies and
practices, research is necessary to:

. Develop techniques for enhancing methane
generation in cases where the methane can be
captured and utilized.

. Develop cost beneficial uses of recovered methane
from landfills (particularly small landfills),
such as lower cost electricity generation
technologies.

Wastewater Treatment Systems. Technologies and
practices exist to manage wastewater without producing

methane emissions, including aerobic treatment and
anaerobic treatment with methane recovery and
utilization. Therefore, methane emissions from
wastewater treatment systems can technically be almost
entirely eliminated. In many circumstances, anaerobic
treatment with methane recovery and utilization appears
to be cost effective due to the value of the energy
produced. To promote the reduction of methane
emissions from wastewater treatment systems, the best
wastewater management practices should be defined based
on the demonstrated technical and economic feasibility
and the other environmental benefits of the various
existing approaches for managing wastewater. The
approach of collecting and utilizing the methane
produced by anaerobic wastewater treatment should be
examined as part of the process of defining best
practices. In some areas, existing wastewater
management technologies may need to be demonstrated.

47



EXHIBIT A-3

METHANE EMISSIONS FROM AGRICULTURAL SOURCES

THROUGH 2025

METHANE EMISSIONS FROM RICE

160

§ 126 SJ

: Ss

s L

g

$ 100 SS) SSE Asia

2 N)

3 7 ~

4

§ 50 NS

3S 7 Other Developing

:

28 cP Asia
° Seca USSR & E. Europe
1986 1990 2000 2010 2020 202°?

Year

METHANE EMISSIONS FROM ANIMALS:
ENTERIC FERMENTATION AND WASTES

200
180
160
140
120
100

80

60

Other Developing

Latin America
CP Asia

USSR & E. Europe

Teragrams Methane/Vear

40
20

)
1966 1990

Bf united states
2000 2010 2020 2025
Veer

Page A-10



Seiler W. and R. Conrad (1981), "Contribution of Tropical
Ecosystems to the Global Budgets of Trace Gases, Especially CH4,
H2, CO and N20," In: any E. Dickinson (Ed. ).

tat Climate era , Wiley and Sons,
New York, ves 133-160,

Seiler, W. (1989), "Role of Rice Cultivation in Global Emissions
of Trace Gases," Proceedings of the Workshop on Greenhouse Gas
Emissions from Agricultural Systems of the IPCC Response
Strategies Working Group, December 12-14.

Washida, N. (1989), "Methane Measurements and Alternative
Management Practices: Recent Work in Japan II," Proceedings of
the Workshop on Greenhouse Gas Emissions from Agricultural
Systems of the IPCC Response Strategies Working Group, December
12-14.

Yagi, K. and K. Minami (1990), “Effects of Organic Matter
Applications on CH4 Emissions from Japanese Paddy Fields," Soils

and the Greenhouse Effect, A.F. Bouwman (ed.), John Wiley & Sons,
New York, pp. 467-473.

Page D-22



quality feeds. The number of animals in this situation
(at least part of the year) is large, including many of
the world's grazing animals (e.g., in parts of North
America, Africa, and Australia) and many animals fed
crop residues in Asia. Measurements of CH, emissions
from these animals under realistic field conditions are
needed.

The data developed under these analyses could then be used ina
model of animal and waste management practices to improve the
estimates of CH, emissions.

To develop these data needed to improve estimates of CH,
emissions, techniques for taking field measurements of CH,
emissions from livestock need to be developed and implemented.
These measurements will not only provide better estimates of
current emissions but will also validate the effectiveness of
emissions reductions techniques.

Indirect calorimetry is the laboratory technique currently
used to measure CH, emissions from animals. The method involves
placing an animal ‘in confinement for a period of several days,
and measuring the amount of inputs (feed, oxygen, carbon dioxide,
water) and outputs (feces, CH,, heat) from the chamber. Field
techniques are required as companions to calorimetry that can be
implemented under field conditions and for grazing animals.

Emissions Reductions

While many uncertainties exist, it appears that there are a
number of technologies that can potentially reduce methane
emissions from livestock systems by 25 to 75 percent per unit of
product. The reductions that are achieved depend upon how
effectively interventions are deployed and how interventions
affect the supply and demand for livestock products.°

Potential options for reducing CH, emissions should be
evaluated in terms of:

. Time frame: the period when the option may become viable
(near term vs long term).

. Applicability: the categories of animals for which the
option may be used to reduce emissions (e.g. dairy cows in
India).

6 Interventions could potentially lead to an increase in

methane emissions by increasing the consumption of livestock
products.

Page 0-15



EXHIBIT 2

OBSERVED INCREASES IN METHANE CONCENTRATIONS

1.7

15

Source:

CH,
PPMV
= J. 4. it ut 1 [oe | i A 7
1978 79 80 81 82 83 84 85 86 87 88

YEAR

Blake, D.R. and F.S. Rowland, "Continuing Worldwide

Increase in Tropospheric Methane, 1978 to 1987," Science,

March 4,

1988.



. reducing (by about 15 percent) the size of the herd
necessary to support the lactating cows (i.e., dry cows and
growing heifers).

Economic evaluations indicate that the use of bST can be economic
in its own right. Similar analyses of other productivity
enhancing agents should also be performed.

Strategic supplementation of ruminants fed crop residues and
byproducts to correct nutrient deficiencies. Large numbers of

cattle and buffalo are fed crop residues and byproducts. In many
areas, these feeds may be lacking in certain vital nutrients
(e.g. nitrogen), inhibiting digestive efficiency and
productivity. Research and practice in India has shown that
supplementing the diets of these animals with locally produced
supplements dramatically improves rumen performance and animal
productivity. These supplements reduce CH, emissions per amount
of product produced by:

. balancing the fermentation patterns in the rumen so that the
CH, yield (the amount of CH, produced per amount of feed
consumed) is reduced;

. increasing the reproductive efficiency of the animals so
that the maintenance requirements of the breeding herd are
diluted significantly;

. increasing the milk yields per cow so that the maintenance
requirements of the individual lactating cows are diluted
significantly; and

. reducing the time required to reach maturity for individual
animals (particularly cows) so that they spend a larger
portion of their lives in a productive mode.

Large reductions in CH, emissions per amount of product produced
appear to be achievable with the supplementation strategies
currently being adopted in India. The feasibility and benefits
of implementing these strategies in additional locations should
be assessed.

i efficiency to
requirements. Increasing the reproductive efficiency of animals
will reduce CH, emissions by reducing the size of the brood herd
needed to sustain a given population of animals.

Alter microbial conditions in the rumen. CH, emissions may

be reduced by balancing the microbiological processes in the
rumen so that maximum efficiency is achieved. Techniques for
achieving this balance included better feeds, feed combinations,
feed treatments and bio-engineering. Options for promoting

Page 0-17



remaining emissions are from natural sources which are
associated with swamps, marshes, lakes, and oceans.

The most important anthropogenic methane sources are
related to agricultural activities, which account for
about 50% of the total methane emissions or 70% of the
anthropogenic methane released.

Rice fields are an important source of methane emissions on
a global scale.

2.1

Flooded rice fields emit significant quantities of
methane produced by microbial, anaerobic decay of
organic matter. Current estimates, based on limited
measurements, suggest that rice fields account for up
to 20% of global methane emissions and 30% of the total
anthropogenic emissions from agricultural activities.

To meet the rice requirements of increased population,
rice production has to increase from the current level
of 450 million tons to 550 million tons by the year
2000 and to 750 million tons by the year 2020. Since
the projected increase can only be achieved by
increasing the yield and harvest area of flooded rice,
methane emissions may increase by 20% in the next
decade.

Reductions in methane emissions are needed to stabilize
atmospheric concentrations of methane and/or return them to
lower concentrations.

3.1

Based on the current imbalance between methane
emissions and destruction in the atmosphere, a 10-20%
reduction in anthropogenic methane emissions is
required to stabilize atmospheric concentrations at
their current levels. Additional reductions would be
necessary to reduce atmospheric concentrations.

Due to the variety of methane emissions sources,
reducing emissions from one or two sources will not be
sufficient for stabilizing atmospheric concentrations.
Reductions in each of the major sources is likely to be
necessary.

A 10% reduction in methane emissions from rice fields
will contribute about 15-20% of the emissions
reductions required to stabilize atmospheric
concentrations of methane. A 20% reduction in methane
concentrations will contribute about 30-50% of the
needed reductions.

51



Acknowledgements

Several organizations have contributed to the workshops upon
which this report is based. These include the Japan Environment
Agency, the United States Department of Agriculture, the United
States Agency for International Development and the United States
Environmental Protection Agency. The following individuals from
these organizations deserve special acknowledgement for their
contributions: Katsuya Sato (Japan Environment Agency), Shuzo
Nishioka (Japan Environment Agency), Dennis Tirpak (US EPA), Gary
Evans (USDA), Ken Feldman (US AID), and David Mobley (US EPA).

In addition, the session chairs and overview speakers who
contributed to the success of the workshops need to be thanked:
Heinz-Ulrich Neue (International Rice Research Institute), Pedro
Sanchez (North Carolina State University), Richard Morgenstern
(US EPA), Dan Lashof (Natural Resources Defense Council),
Wolfgang Seiler (Fraunhofer Institute), John Reilly (USDA), David
Norse (FAO), Elaine Matthews (NASA), Ken Andrasko (US EPA), Alan
Miller (Center for Global Change), Rob Swart (National Institute
of Public Health and Environmental Protection, Netherlands),
Cathy Zoi (US EPA), Dina Kruger (US EPA), and Kathleen Hogan (US
EPA).

The organizational and management efforts of Lauretta Burke
(US EPA), Kathy Ackley (ICF Incorporated), Shirley Toth (US AID),
Leslie Gallo (Science and Policy Associates), David Debusk (US
EPA), and Alex Greenwood (ICF Incorporated) were greatly
appreciated. Finally, Michael Gibbs of ICF Incorporated deserves
special thanks for developing a first draft of this report.



Peet Soot, PhD
northwest Fuel Development,

Ine.
PO Box 25562
Portland, OR 97225

Tel: 503-297-6291
Fax: 503-297-1802

Kathleen Stephenson
The World Bank

1818 H Street, NW
Washington, DC 20433

Tel: 202-477-2770

Dr. David Streets

Argonne National Laboratory
BID/362

9700 South Cass Avenue
Argonne, IL 60439

Tel: 708-972-3448
Pax: 708 972-3206

Nicholas A. sundt

Office of Technology
Assessnent

600 Pennsylvania Avenue, SE
Washington, DC 20003

Tel: 202-544-4058

Bent R. Svensson
International Energy Agency
2 gue Andre - Pascal

76775 Paris

France

Tel: 33-1-45249455
Fax: 31-1-45249988

Prof. Robert J. swart
RIVKM

PO Box 1

372 BA Bilthoven
Netherlands

Tel: 31 30 743026
Fax: 31 30 250740
Telex: 47215 rive nl.

Istvan Ssucs

Mecsek Coal Mining Co.
7629 Pecs

Komjat, Hungary

Tel: 36 72 25930
Fax: 36 72 25880

Yasuo Takahashi

Climate Change Division

Us EPA

7500 Woodmont Avenue, #8-602
Bethesda, MD 20814

Tel: 301-907-9568

Kazuhiko Takemoto
The World Bank

1818 H Street, NW
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Tel: 202-477-4674
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Telex: ITT 440098

Shiro Takenaka
Osaka Gas Co., Ltd.
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Suite 2805

New York, MY 10152

Tel: 212-980-1666
Pax: 212-832-0946

Page E-21



Using these estimates, Cicerone and Oremland report annual
CH, emissions to be in the range of about 450 to 640 Tg per year,
with a central estimate of about 540 Tg per year.” The
uncertainty in Cicerone and Oremland's estimate of total annual
emissions is driven primarily by uncertainty regarding the
destruction (or loss) rate of CH, in the atmosphere. For
example, if the lifetime of CH, in the atmosphere is as short as
8.1 years (i. e., the destruction rate is faster), then total
steady-state emissions would have to be 4,800 Tg + 8.1 years =
593 Tg per year. When added to the observed rate of CH,
increase, the total emissions are about 640 Tg. Similarly, a
lifetime of 11.8 years implies total annual emissions (including
the observed increase) of about 450 Tg per year.

As this example indicates, the uncertainty in total annual
CH, emissions (540 Tg + approximately 100 Tg) is primarily
associated with the estimated destruction rate for CH, in the
atmosphere. The contribution to the overall uncertainty from the
uncertainty in the rate of change in the atmospheric CH,
abundance is small-by comparison.

A.2 Emissions Sources

Although total annual global CH, emissions are reasonably
constrained by measurements, no such constraints can be applied
to most of the known sources of CH, emissions. Consequently, the
individual contribution of the identified sources is uncertain.

The major sources of CH, emissions (summarized in Exhibit
A-1) include:

3(.. continued)
average residence time of the compound in the atmosphere. For
example, a lifetime of 10 years implies that approximately 1/10
or 10 percent of the atmospheric abundance of the compound is
destroyed each year through various processes (e.g., chemical
reactions).

* Cicerone and Oremland report a range of 400 to 640 Tg
(p. 315 and Table 4). However, they also report a range of 405
to 595 Tg for the emissions necessary to maintain the currently
observed concentration of CH, at near steady state (p. 312).
When combined with the emissions necessary to produce the
observed increase in concentrations (40 to 46 Tg per year),
annual emissions must be in the range of 450 to 640 Tg per year.
The source of the discrepancy is not evident at this time.

Page A-2



-- that of slowing warming and that of ultimately limiting
warming. Actions to stabilize global climate change should
pursue simultaneous strategies that limit the emissions of
different trace gases with these widely differing impacts.

23





Kathleen Hartnett

National Cattlemen’s Association
1301 Pennsylvania Ave, NW
Suite 300

Washington, D.C. 20004
USA.

Phone: 202-347-0228

Fax: 202-347-6380

Kate Heaton

U.S. Environmental Protection Agency
PM-221

401 M Street, SW

Washington, D.C. 20460

USA.

Phone: 202-382-5648

John Hoffman

U.S. EPA

Office of Air and Radiation

401 M Street, SW

Rm. 739, West Tower, ANR 445
Washington, D.C. 20460
USA.

Phone: 202-382-4036

Fax: 202-382-6344

Kathleen Hogan

US. EPA

Office of Air and Radiation

401 M Street, SW

Rm. 739, West Tower, ANR 445
Washington, D.C. 20460

USA.

Phone: 202-475-9374

Fax: 202-382-6344

Steven Holman

U.S. Environmental Protection Agency
Environmental Research Laboratory
200 SW 35th Street

Corvallis, OR 97333

USA.

Phone: 503-757-4692

Mary Horne

CGIAR

1818 H Street, NW
Washington, D.C. 20433
USA.

Phone: 202-334-8017

David Howarth

ICF Inc.

9300 Lee Highway
Fairfax, VA 22031-1207
USA.

Phone: 703-934-3586
Fax: 703-934-9740

Braulio D. Jimenez

Oak Ridge National Laboratory
Environmental Sciences Division
P.O. Box 2008

Oak Ridge, TN 37831-6036
USA.

Phone: 615-574-7321

Fax: 615-574-4946

Anthony S. R. Juo

Texas A & M University

Department of Soil and Crop Sciences
College Station, TX 77843

USA.

Phone: 409-845-8841

Fax: 409-845-0456

Telex: 880544 TWX

Donald D. Kaufman

US. Department of Agri
Soil Microbial Systems Lab
Building 318, Room 108
Beltsville, MD 20705
USA.

Phone: 301-344-3163

Peter Kettle

National Science Program Manager

Ministry of Agriculture and Fisheries Technology
P.O. Box 2526

Wellington

NEW ZEALAND

Phone: 64-04-720-367

Fax: 64-04-744-163

Telex: 31532 NZ MAF

Trish Koman

ICF Inc.

9300 Lee Highway
Fairfax, VA 22031-1207
USA.

Phone: 703-934-3701

Page E-4



-- Techniques for achieving defaunation should be
defined and demonstrated under field conditions.
The costs of administering these techniques should
be estimated and balanced against the benefits of
improved animal performance. Initial assessments
are that the costs of the defaunation may be
economically justified solely by improvements in
performance.

-- The overall system-wide CH, emissions reduction
anticipated must be estimated.

ti f i t (2)
sidui ~products to correct nutrien
deficiencies. Research and practice in India and other

developing countries indicate that improved rumen
performance can be achieved through the use of locally-
produced supplements. This improved rumen performance
allows for significantly improved animal productivity
and increased digestion efficiency, both of which can
contribute to significant CH, emissions reductions per
unit of animal product. Based on experience in India,
strategic supplementation systems can be self-
sustaining and economic investments.

-- While it has been estimated that strategic
supplementation can reduce CH, emissions
significantly in individual segments of animal
populations (e.g., by over 60%), evaluations of
overall system-wide performance must be performed
that reflect the diverse products produced by
cattle and buffalo. In particular, the economic
responses to changes in costs of production and
demand must be examined. Also, social impacts
must be evaluated. Preferred strategies that
reduce CH, emissions through the use of
supplementation should be identified, as well as
the obstacles to their implementation.

- Key areas where strategic supplementation should
be investigated include those countries with large
cattle and buffalo populations. Examples include:
additional expansion in India; Pakistan;
Bangladesh; Sub-Saharan Africa; and China.
Assessments of these areas should be performed
that include infrastructure and marketing needs as
well as potential local sources of supplementation
inputs.

59



models that have been used in analyses of global climate change
performed for EPA and as part of the IPCC process, '° The model
was used for the analysis presented here because it estimates the
composition of the atmosphere (including methane concentrations)
based on the interactions among the full set of greenhouse gases.

This analysis relied on two scenarios of future emissions
that bracket the Business-as-Usual Scenario developed by the
Ipcc:

. Rapidly Changing World scenario (RCW) includes rapid
economic growth and increases in greenhouse gas
emissions from fossil fuel use and land use changes
(deforestation); and

. Slowly Changing World scenario (SCW) includes slower
economic growth and smaller increases in greenhouse gas
emissions.

These two scenarios describe a wide range of potential future
emissions and useful for providing sensitivity analyses. These
scenarios are described in detail in EPA (1989).

These two scenarios were used to estimate the level of
methane emissions that must be achieved in order to stabilize
methane concentrations at approximately current levels. The
levels of emissions of all the other greenhouse gases were not
changed from the values specified in the RCW and SCW scenarios.

Exhibit 6 presents the estimates of methane emissions in the
cases examined. As shown in the exhibit, the uncontrolled
methane emissions in the RCW and SCW scenarios are estimated at
about 505 Tg per year in 1985. This level of emission is
slightly lower than the middle estimate provided in Cicerone and
Oremland (1988), but is toward the middle of the accepted range
of global annual emissions. Regardless, the precise magnitude of
the initial emissions does not affect the result of this
analysis.

In the RCW scenario emissions are estimated to grow to about
1,000 Tg per year by 2100. To stabilize concentrations at about
1.7 ppmv (1,700 ppbv), the ASF indicates that methane emissions
must be reduced to about 475 Tg in the near term. This is a
reduction of about 30 Tg from current levels of emissions. This

10 See EPA (1989) for a description of the ASF. The ASF

was used in analses for the May 3lst, 1990 Intergovernmental
Panel on Climate Change Energy and Industry Subgroup Report.

16



from gob areas. The parameters that define the
circumstances under which this methane can be produced
for use must be defined. Demonstration of techniques
to use ventilation air in turbines is also a high
priority. Techniques for safely collecting and flaring
gas that cannot be recovered for use must also be
described.

. Standard methods for evaluating and estimating methane
emissions from individual landfills is needed. Such
methods would enable the potential methane emissions
from individual landfills to be evaluated and
controlled or recovered as appropriate.

. The transmissions losses from the USSR gas
transmissions system need to be quantified and
evaluated. The opportunities to reduce these emissions
need to be identified.

. The resources available locally to provide strategic
supplementation to cattle that are feeding on poor
quality forages must be identified. The system for
formulating and producing these feeds must be
described.

. Techniques for recovering and utilizing methane
emissions from anaerobic waste lagoons need to be
described. The experience with existing systems should
be summarized. The number and size of potential target
lagoons needs to be described.

By undertaking these and similar research efforts, the preferred

approaches for reducing methane emissions can be defined and
described in detail.

33



Kathleen Hogan

U.8. EPA, AMR 445
402 KM Street, SW
Washington, DC 20460

Tel: 202-475-9304
Pax: 202-382-6344

John Homer

The World Bank

1818 H Street, NW
Washington, DC 20433

Tel: 202-477-1234

Mangesh Hoskote

AID Office of Energy

Private Sector Energy Develop.
Pro.

1611 M. Kent st.

Buite 200

Rosslyn, VA 22209

Tel: 703-524-4400
Pax: 703-524-3164

Art Jaques

Environment - Canada
Place Vincent Massey
18th Floor

351 St. Joseph Blvd.
Ottawa, Ontario K1A OH3
Canada

Tel: 819-994-3098
Fax: 819-953-9542

Jia Yunshean

Ministrry of Energy (MOE)
137 FPuyou street
Beijing, 10031

China

Tel: 054131-566
Pax: 0016077
Telex: 222866 MEDIC CN

Dr. Catherine A. Johnson
British. Gas plc.

London Research station
Michael Raod

Fulham, London, SW6 2AD
England

Tel: 01-736-3344

Julian W. Jones

USEPA

Air and Energy Engineering
Research Laboratory

Global Emission & Control Div.
(MD-62)

Research Triangle Park, NC
27911

Tel: 919-541-2489

Miecsyslaw Kacsmarcsyk
Polish Oil and Gas Company
Warsaw, Poland - 00.537
ul. Krucsa 6/14

Tel: (004822) 28-16-42
Fax: 29-08-56
Telex: 81-34-66 pl

Bent Karll

Nordic Gas Technology Centre
Dr. Neergaards Ve} SA
DK-2970 Horsholm

Denmark

Tel: 45 45 76 69 95
Fax: 45 42 57 16 44

James L. Kelley

U.8. Dept. of Energy
PE-70, Rm 4G-036

1000 Independence Ave., SW
Washington, DC 20585

Tel: 202-586-8420
Fax: 202-586-2062

Page €-15



4.3 Technologies and practices for reducing emissions from
flooded rice fields need to be developed, demonstrated,
and assessed. In addition, the costs and benefits need
to be evaluated.

4.4 Technologies such as new cultivars and improved water
management may have little impact on farm costs, while
increased use of fertilizer may add to the costs.
Future assessments should attempt to identify the full
costs and benefits of new technologies.

In order for the benefits of future research on technologies
and practices to achieve their potential, governments should
examine existing agricultural policies. Analyses of many
alternative policies are needed, including: economic
policies such as subsidies, taxes, and pricing and trade
barriers; cultural practices; technology transfer measures;
education programs; and international financial assistance
measures.

53



Methane Concentration (ppbv)

EXHIBIT 7

METHANE CONCENTRATIONS AND METHANE STABILIZATION

4,400

4,000 -

3,600 +

3,200 +

RCW Scenano

RCW and SCW Scenarios with Stabilization Emissions

1985

2010 2035 2060 2085
Year

Two base scenarios of methane concentrations were
estimated: Rapidly Changing World (RCW) and
Slowly Changing World (SCW) from EPA (1989).
These scenarios represent a wide range of
potential future emissions for greenhouse gases.

The methane concentrations estimated using the
emissions needed to stabilize concentrations are
shown as the "Stabilization Emissions" scenarios.
As shown, these scenarios produce methane
concentrations on the order of 1,700 ppbv.

19



Gary Breitenbeck

Louisiana State University
Department of Agronomy
Baton Rouge, LA 70803-2110
USA.

Phone: 504-388-1362

Fax: 504-388-1403

William Budd

Washington State University
Program in Environmental
Science and Regional Planning
Troy Hall - 305

Pullman, WA 99164-4430
USA.

Phone: 509-335-8536

Martin Buechi

Swiss Embassy

2900 Cathedral Ave., NW
Washington, D.C. 20008-3499
USA.

Phone: 202-745-7947

Fax: 202-387-2564

Matthew Buresch
ICF Inc.

9300 Lee Highway
Fairfax, VA 22031
USA.

Phone: 703-934-3000

Lauretta Burke

U.S. Environmental Protection Agency
PM-221

401 M Street, SW

Washington, D.C. 20460

USA.

Phone: 202-475-6632

Floyd Byers

Texas A & M University
Department of Animal Sciences
College Station, TX 77843
USA.

Phone: 409-845-5065

Bernard H. Byrnes

International Fertilizer Development Center
P.O. Box 2040

Muscle Shoals AL 35662

USA.

Phone: 205-381-6600

Fax: 205-381-7408

Telex: 810-731-3970 (IFDEC MCHL)

Whitney Carroll

Science and Policy Associates
1333 H Street, NW

The Landmark Building, Suite 400
Washington, D.C. 20005

USA.

Phone: 202-789-1201

Fax: 202-789-1206

Robert W. Clare

Ministry of Agriculture, Fisheries, and Food
Rosemaund EHF

Herefordshire, HRI 3PG

UNITED KINGDOM

Phone: 820-444

Fax: 44-1-238-6700

Michael Colby

World Bank

Strategic Planning Division, $12-042
1818 H Street, NW

Washington, D.C. 20433

USA.

Phone: 202-473-8221

Fax. 202-477-0174

Roger Dahlman

US. Dept. of Energy
ER-76

Washington, D.C. 20545
USA.

Phone: 202-353-4951
Fax: 202-353-3884
Omnet: R.DAHLMAN

Wayne L. Decker

University of Missouri-Columbia
701 Hitt Street

Columbia, MO 65211

USA.

Phone: 314-882-6592

Page €-2



These estimates of CH, emissions are based on rough assumptions
about overall leakage rates. Several industry studies have
recently provided some new insights into potential emissions.

Pac s & E ic Uni For Gas Stud

Pacific Gas & Electric (PG&E) prepared a study on its
"unaccounted for" gas (UFG) at the request of the California
Public Utility Commission (CPUC). Pipelines and gas distribution
companies routinely report figures for UFG. These figures are
accounting-oriented, essentially a difference account to make the
"volume in" equal the "volume out."

The CPUC was concerned about the unexplained variation in
PG&E's UFG account which had been as low as 0.94 percent of
PG&E's throughput volumes in one year and as high as 4.65 percent
in another while averaging 2.2 percent. This UFG cost ratepayers
approximately $54 million in 1985.

The PG&E study found that in 1987 total leakage from the
PG&E system was about 1,182 MMcf (million cubic feet), or about
0.14 percent of the total gas receipts in 1987. Of this total,
about 223 MMcf was associated with the operation of pneumatic
instruments, 307 MMcf was associated with maintenance activities,
and 647 MMcf was leaked from the PG&E distribution and
transmission system (498 MMcf from leaks in the distribution
system). This leakage rate estimate, which includes gas
transmission and distribution, but not gas production or
processing, is much lower than the 2 to 4 percent estimates used
by the atmospheric science community to develop global CH,
emissions estimates for natural gas systems.

PSI Engineering Analysis

Pipeline Systems Incorporated (PSI) has recently completed
an engineering-based estimate of CH, emissions from the
collective components of the oil and natural gas systems in the
U.S., and is considered to be an initial "order-of-magnitude"
estimate of emissions (PSI, 1989). Based on available
engineering data, and results from the PG&E UFG study, PSI
estimated that about 3.1 Tg of CH, were emitted from the U.S.
natural gas system in 1988. This amounts to about 160 bcf
(billion cubic feet or thousand million cubic feet), or on the
order of 1.0 percent of total gas usage in the U.S. This
emissions estimate is considered to be quite uncertain because
data are lacking in many areas needed to estimate emissions
precisely. Additionally, emissions rates likely vary across the
hundreds of gas facilities in the U.S., making it difficult to
define a single representative emissions rate for the entire
country.

Page 8-4



3.

emissions from large utility and industrial coal-fired
boilers are low (perhaps less than 10 ppm), it appears
that emissions from domestic coal combustion processes
could be significant (perhaps on the order of 10-100
Pp).

Technical Potential for Reducing Emissions

3.1 Degasification technologies are used successfully in
many countries to maintain mine safety and enhance
productivity in mines with high methane emission
levels. The benefits of using these technologies
include increased safety, reduced downtime, and reduced
ventilation costs and capacity requirements.

3.2 Current recovery operations at some mines in the United
States and other countries have reduced methane
emissions to the atmosphere associated with mining
operations by 30-40 percent. The effectiveness of
degasification operations at these and other mines must
be assessed on a site-specific basis and will depend on
many factors, including the methane content of the coal
and surrounding strata, the magnitude of the methane
emissions, the type and age of the mine, the time
available for degasification, and geologic conditions
at the site. At some mines with high methane
emissions, degasification systems might be able to
recover higher levels of methane, while at other mines
the recovery potential will not exist at all.

3.3 Most current degasification programs are not being
undertaken because of the methane recovery potential,
but instead are essential to maintain mine safety.
Thus, the current experience with methane recovery
might represent economically attractive recovery
levels, as opposed to the recovery levels that could be
technically achieved.

3.4 Additional benefits result from utilization of the
recovered methane. These benefits can include revenue
or fuel cost savings from production of the gas and
reduced methane emissions to the atmosphere.

3.5 Strategies for using recovered methane should seek to
minimize methane emissions to the atmosphere. Many
technologies are available to use methane recovered
during coal mining. Choices among these technologies
depends on methane production rates, gas quality, local
energy markets and other factors.

40



Washida, N. (1989), "Methane Measurements and Alternative
Management Practices: Recent Work in Japan II," Proceedings of
the Workshop on Greenhouse Gas Emissions from Agricultural
Systems of the IPCC Response Strategies Working Group, December
12-14.

WMO (World Meteorological Organization) (1986), Atmospheric Ozone
1985, Global Ozone Research and Monitoring Project Report No. 16,
NASA, Earth Science and Applications Division, Washington, D.C.

Zimmerman, P.R., J.P. Greenberg, S.O. Wandiga, and P.J. Crutzen
(1982), "Termites: A Potentially Large Source of Atmospheric
Methane, Carbon Dioxide, and Molecular Hydrogen," Science, Vol.
218, pp. 563-565.

Page A-15



4.4

feeding practices toward low-CH, rations could
potentially reduce CH, emissions by large amounts in
certain circumstances.

-- The size and location of the animal populations
for which feed modifications are a promising
alternative must be identified.

-- Promising strategies for lowering CH, should be
identified for these populations of animals,
taking into account the costs and availability of
the candidate feeds. Opportunities for reducing
costs and increasing the availability of the
candidate feeds should be explored.

-- The potential CH, emissions reduction from these
approaches should be quantified (e.g., using rumen
digestion and animal production models) and
verified with experimental data.

Us bs' ia nt: ncre duct i

cow. The use of bST (or similar technologies) can
reduce CH, emissions per amount of product produced by:
(1) further diluting the maintenance requirements of
individual lactating cows (a reduction of about 3 to
5%); and (2) reducing (by about 15%) the size of the
herd necessary to support the lactating cows (i.e., dry
cows and growing heifers). Economic evaluations have
indicated that the use of bST is economic in its own
right in some circumstances.

-- The potential system-wide reduction in CH,
emissions associated with the use of bST should be
estimated so that its importance in this regard
can be assessed. This assessment should be
performed with a range of accepted values for the
anticipated performance response from the
administration of bST.

-- The CH, emissions implications of using other
growth regulating agents should also be evaluated.

Defaunation of the rumen. Based on experimental data,
under certain feeding systems, the elimination of
protozoa in the rumen results in lower CH, emissions
and may enhance animal performance.

-- The population of animals whose performance could

be increased and whose CH, emissions could be
decreased through defaunation should be estimated.

58





APPENDIX D

AGRICULTURAL SOURCES

D.1 Flooded Rice Cultivation

Recent work on global emissions of methane (CH,) from
flooded rice fields estimates that 60 to 170 Tg of CH, are
emitted annually. This accounts for about 20 percent of the
global CH, budget. These estimates incorporate very little
available’ data on CH, fluxes from rice fields in Asia, an area
from which little data have been available and where over 90
percent of the world's rice is produced. Until more measurements
from Asia are available, CH, emissions from rice cultivation need
to be regarded as highly uncertain.

Other estimates of CH, emissions from rice cultivation have
been developed over the last twenty years, and it is useful to
understand their particular limitations. Some of the earliest
reported estimates are based on Koyama's measurements of CH, flux
from laboratory cultures of rice paddy soil. Extrapolation of
this data to other soils yielded a global estimate of 190 Tg per
year of CH, from rice paddies. Revisions by Ehhalt (1974) and
Ehhalt and Schmidt (1978) to account for increases in rice
cropping area resulted in global estimates of 220 to 280 Tg/yr.
Since methanogenesis is highly sensitive to environmental
conditions it seems likely that these estimates which are based
on laboratory experiments do not adequately reflect the wide
array of situations found in the field.

The first set of emission estimates based on field
measurements was provided by Cicerone and Shetter (1981) from
work in a California rice paddy. Extrapolation of their results
to a global scale yielded a much lower estimate of 59 Tg/yr of
CH,. Comprehensive field measurements in Spanish and California
rice paddies by Seiler (1984) resulted in global estimates of 30
to 75 Tg/yr of CH,. Somewhat higher global emission rates (70 to
170 Tg/yr) were found by Holzapfel-Pschorn and Seiler (1986) when
using semi-continuous field measurements of fluxes from Italian
rice paddies over a whole vegetation period. It is now believed
that the lower rates observed in Spanish paddies may be due to
the inflow of Mediterranean water containing sulfate which may
suppress CH, formation. Recent measurements have also been made
by Yagi and’ Minami (1990), Minami (1989), and Washida (1989) in
Japan which may represent the extent of emissions from Japanese
soils.

Page 0-1



EXHIBIT D-2

ACTUAL AND PROJECTED HARVESTED RICE AREA AND RICE PRODUCTION

BY RICE ENVIRONMENT IN SOUTH AND SOUTH EAST ASIA

1980 2000
Area Production Area Production
Environment 1000 ha % mt % 1000 ha % mt %
Irrigated 28,867 33 94.2 52 52,741 42 232.1 59
Shallow Rainfed 30,375 35 54.7 30 39,905 32 104.6 27
Medium Deep Rainfed 11,587 13 16.2 9 13,114 11 30.8 8
Tidal Wetland 5,290 6 5.3 3 6,046 5 9.1 2
Upland 11,593 13 11.6 _6 12,793 10 18.0 _5
Total 87,712 100 182.0 100 124,599 100 394.5 100

Source: IRRI, 1988.

Page D-4



EXHIBIT 9 (Continued)

OPPORTUNITIES TO REDUCE METHANE EMISSIONS

Reductions
Technically Needed for
Feasible Stabilization
Emissions Source/ Reductions by 2000
Reduction Option (ig/yr) (Tg/yr) Comments
Ani Was and Wastewater 50 to 90 percent 50 percent of Animal waste lagoons are
Treatment: Recover methane from of Lagoon emis- the feasible primarily used in situations
uncontrolled anaerobic treatment sions: 5 to9 Tg reductions from with large concentrations of
lagoons. from animal animal wastes animals. The recovered methane
wastes and 5 to and 25 percent is a useful energy source. The
9 Tg from waste- of the feasible estimates for anaerobic treat-

Rice Cultivation: Improved
irrigation, fertilizer use and
cultivar selection.

water treatment. reductions from ment of wastewater are parti-
wastewater: 4 to cularly uncertain, and may be
7 Tg. primarily at food processing
facilities in developing
countries.

10 to 30 percent None. Long-term
of emissions per reductions only.
product: 6 to

50 Tg at current

levels of rice

production.

Total Emissi Reduction

64 - 163 Tg 24 - 49 Tg

27



Jerry Gardetta

southern California Gas Co.
810 8. Flower st.

Los Angeles, CA 90017

Tel: 213-689-3365
Pax: 213-689-17126

Michael J. Gibbs

IcF Incorporated

Suite 2400

10 Universal sity Plasa
Universal City, CA 91608

Tel: 818-509-7186
Fax: 818-509-3925

Roger Glickert

Energy Systens Associates
1130 17th Street, NW
Buite 520

Washington, DC 20036

Tel: 202-296-7961

John M. Goldsmith, Jr.
The New River Gas Company
921 Vicar Lane
Alexandria, VA 22303

Tel: 703-751-9258

Kjell Hagemark
statoil
7004 Trondheim
Norway

Tel: 47-7-584248
Pax: 47-7-564618
Telex: 55278 STATD N

Thor Havryluk

Geo Met. Inc

2 Penn Center West
suite 120
Pittsburgh, PA 15276

Tel: 412-788-4755

Nelson E. Hay

American Gas Association
1515 Wilson Blvd.
Arlinngton, VA 22209

Tel: 703-841-8475
Pax: 703-841-8406

Tetsuo Hayakawa

Waste Management Div.
Ministry of Health & Welfare,
Japan

1-2-2, Kasumigaseki, Chiyoda
Tokyo, 100 Japan

Tel: 03-503-1711 ex 2474
Pax: 03-502-6879

Stephen Hirsfeld

GRCDA

8750 Georgia Ave.

Suite 140

Silver Spring, MD 20910

Tel: 301-585-2898
Fax: 301-589-7068

John Hoffman

U.S. EPA, ANR 445
401 M Street, SW
Washington, DC 20460

Tel: 202-382-4036
Fax: 202-382-6344

Page E-14



emissions from many sources would be required in many
countries.

Although emissions-reduction programs would be required
in many countries to achieve significant emissions
reductions, individual countries can make valuable
contributions by developing, demonstrating, and
implementing emissions-reduction technologies.

Stabilizing methane concentrations at or below approximately
current levels may be achievable with identified emissions
control options that are profitable or low cost, but
additional analyses are necessary.

3.1

The recent comprehensive observational record indicates
that reduction in methane emissions of about 30 to

45 Tg’ per year will stabilize atmospheric methane
concentrations assuming that the rate of methane
destruction in the atmosphere remains unchanged. This
level of emissions reduction is about 10 percent of
current anthropogenic emissions.

Analyses using models indicate that following a
reduction in emissions of 30 to 45 Tg per year,
stabilization could be maintained if the long-term
growth in methane emissions was restrained to about 2
to 3 percent per decade.

Using the emissions reduction techniques identified at
the IPCC Workshops it appears technically feasible to
reduce methane emissions by about 67 to 170 Tg per
year. While feasible, it is unlikely that this level
of emissions reduction can be achieved fully in the
next 10 years. Further detailed evaluation of these
potentials is needed.

Based on information presented at the workshop it is
possible that profitable and low cost options can be
implemented to reduce emissions by about 25 to 50 Tg in
the next 10 years. These emissions reductions will be
adequate to stabilize atmospheric methane
concentrations at approximately current levels.
Additional analysis is required to improve the estimate
of emissions reductions that can be achieved in the
next 10 years.

3

1 Tg = 1 teragram = 10 grams = 10° kilograms = 1 million

metric tons.



agricultural soils. Emissions from burning crop residues and the
routine burning of savannahs may be reduced though stable
agriculture, including use of chemical and organic amendments,
and improved forage species and management systems.

Policy options developed to reduce methane emissions from
biomass burning must have value to the farmer beyond the
greenhouse gas-reducing benefits. Policies must not hamper
national food security goals and should have value to the nation
in reducing net costs of competition on the world market. The
pressure to convert forest land to crop and pasture land needs to
be reduced, in turn reducing emissions from burning, soil
exposure and erosion. Increasing the productivity of croplands
on suitable soils using appropriate, intensive systems will have
that effect. Reclaiming and restoring degraded agricultural
lands should also be explored, in addition to enhancing the
indigenous uses of native forests and establishing forest
cropping systems to reduce the demand for further deforestation.

Education programs which teach improved organic-residue
management, and provide an understanding about the consequences
of soil degradation, need to be developed and proliferated.

Collaborative research among scientists in developed and
developing countries is needed to assure consideration of
regional and local physical and cultural factors, with special
focus on carbon and nitrogen cycling, burning practices and
soils. In addition, research is required in the following areas:

. Remote-sensing and monitoring methodology development is
needed to evaluate the effects of policies to reduce these
practices.

. Better estimates are needed on amounts of biomass burned

annually, instantaneous emissions from the fire front and
longer-term biogenic emissions from a burn.

. Improved efficiency of technologies and devices for
broadcast burning, charcoaling and use of fuel wood for
heating and cooking. These devices and technologies need to
be practical and affordable to indigenous populations.

. Appropriate tree species for agro-forestry by sites and
regions, and the effects of these trees on soils and
cropping systems.

° Potential sinks for greenhouse gases in agricultural systems
of the tropics and the interactions between sources and
sinks. Long-term studies are needed to quantify the effects
of different agricultural management systems on these sinks
and especially on soil properties.

Page 0-19



Rattan Lal

Ohio State University
Dept. of Agronomy
2021 Coffey Road
Kottman Hall
Columbus, OH 43210
USA.

Phone: 614-292-9069
Fax: 614-292-7162

Daniel Lashof

Natural Resources Defense Council
1350 New York Avenue, NW

Suite 300

Washington, D.C. 20005

USA.

Phone: 202-783-7800

Fax: 202-783-5917

George Ledbetter
UNISYN

P.O. Box 2304
Seattle, WA 98111
USA.

Phone: 206-622-6788

R.A. Leng

University of New England
Department of Biochemistry,
Microbiology and Nutrition
Armidale, NSW 2351
AUSTRALIA

Phone: 61-67-73-2707

Fax: 61-67-73-3122

Joel S. Levine

NASA Langley Research Center
Atmospheric Sciences Division
Mail Stop 401 B

Hampton, VA 23665

USA.

Phone: 804-864-6326

Fax. 804-864-6326

Sicui Liang

Office of International Affairs

National Environmental Protection Agency
People’s Republic of China

CHINA

Ariovaldo Luchiari, Jr.
Embrapa/CPAC

KM 18 BR-020

CP 700023

70330 Planaltina - DF
BRAZIL

Phone: 55-61-389-1171
Telex: 61-1621 EBPABR

Elaine Matthews
NASA-GISS
2980 Broadway
New York, NY 10025
USA.
Phone: 212-678-5628
fax. 2\2-y4B- 9552

S. Ahmed Meer

Senior Science Advisor

Dept. of State, OES

Bureau of Oceans International
Scientific and Technological Affairs
Washington, D.C. 20520

USA.

Phone: 202-647-3073

Fax 202-647-5947

Leticia Menchaca

Investigator

Centro de Ciencias de al Atmosfera
Circuito Exterior

Ciudad Universitaria

CP. 04510

MEXICO

Fax 52-5-548-9781

Roger L. Mikeska

National Cattlemen’s Association
1301 Pennsytvania Ave, NW
Suite 300

Washington, D.C. 20004

USA.

Phone: 202-347-0228

Fax —- 202-638-0607

Katsuyuki Minami
National Institute of Agro-Environmental
Sciences
Kannondai 3-1-1
Tsukuba, 305
JAPAN
Phone: 81-298-38-8276
Fax 81-298-38-8199
Page E-5



Jacques Bodelle

Elf Aquitaine

suite 500

1899 L Street, NW
washington, DC 20036

Tel: 202-872-9581
Fax: 202-872-8201
Telex: 277566EXECUR

Jean Bogner

Argonne National Laboratory
Bldg. 362

9700 8S. Cass Avenue
Argonne, IL 60439

Tel: 708-972-3359
Fax: 708-972-7288

Charles M. Boyer II
ICF Resources

9300 Lee Highway
Fairfax, VA 22031

Tel: 703-934-3000
Fax: 703-691-3349

David Branand

National Coal Assocaition
1130 17th st., NW
Washington, DC 20036

Tel: 202-463-2637
Fax: 202-463-6152

Wojciech Brochwics-Levinski
Ministry of Environment
Protection, Natural Resources
and Forestry

Wawelska 52/54, 00-922
Warsaw, Poland

Tel: 253334
Telex: 812816

Charles W. Byrer

U.S. Dept. of Energy
Morgantown Energy Technology
Center

3610 Collins Ferry Road
Morgantown, WV 26507

Tel: 304-291-4547
Pax: 304-291-4469

Scott Bush

Center for Strategic &
International studies

1800 K Street, NW, Suite 400
Washington, DC 20006

Tel: 202-775-3295
202-775-3199

Darcy Campbell

Radian Corporation

PO Box 13000

Research Triangle Park, NC
27709

Tel: 919-541-9000

Francois Cagnon

Gas de France

361 Av. Pdt Wilson

BP 33

93211 La Plaise 8t. Denis
France

Tel: (1) 4922 S206
Fax: (1) 4922 5652
Telex: 236735F

Mark BE. Casada

North Carolina state
University

Bio and Ag Engineering Dept.
Box 7625

Raleigh, NC 24695-7625

Tel: 919-737-3121
Fax: 919-737-7760

Page E-11



identified in various countries. Industry, government
and environmental groups should work together to remove
barriers and to encourage the economic recovery and use
of methane from coal mining.

Government or other financial incentives that recognize
the environmental value of limiting methane emissions
could greatly increase the level of methane recovered
and utilized by mining and other companies.

Financing will be needed to implement methane recovery
systems in developing and Eastern European nations,
even for profitable projects.

International financing organizations should examine
energy and environmental policies and should consider
the economic costs and benefits of mine degasification
and methane utilization, the environmental benefits of
using gas instead of venting it, and the opportunities
for technology transfer, feasibility studies, and
demonstration projects.

42



Increasing emissions of methane are the primary cause
of increasing methane concentrations. Reduction in the
rate of methane destruction in the atmosphere is also a
factor.

Continued increases in methane concentrations will lead
to changes in the distribution and concentration of
tropospheric ozone, which will also contribute to
increases in the greenhouse effect. Furthermore, there
is concern that increasing methane concentrations could
enhance the formation of stratospheric polar clouds,
thus contributing to polar stratospheric ozone
depletion.

Methane's strong ability to absorb infrared radiation
combined with its relatively short atmospheric lifetime
makes methane control an important opportunity for
addressing global climate change.

2.1

On a kilogram for kilogram basis, methane is a more
potent greenhouse gas than carbon dioxide (63 times
greater after 20 years, 21 times greater after 100

years, and 9 times greater after 500 years) .*

Methane's short atmospheric lifetime enables the
control of methane emissions to quickly produce
benefits in terms of changes in atmospheric
concentration and radiative forcing.

As a consequence of its stronger short-term impact and
the short atmospheric lifetime, methane emissions
reductions made in the near term would be substantially
more effective than similar carbon dioxide emissions
reductions in slowing global warming.

Given the many methane emissions sources globally,
emissions reductions from any single country or source
will be small compared to total methane emissions, and
small compared to total emissions of all greenhouse
gases. Consequently, programs to reduce methane

2

These are the values presented are adopted from the IPCC

Working Group 1 Science Assessment Report. The values presented
at the EIS workshop valued the impact of indirect effects
somewhat differently. These include the effect that methane
emissions have on levels of tropospheric ozone and the effect
that methane concentrations have on the lifetime of methane
itself.
in the first year, 55 times greater over 60 years and 10 times
greater over 1000 years.

The values reported at the EIS workshop were 120 times



While many of these opportunities to reduce emissions
are not justified on the basis of current cost
accounting and recovery procedures, they may be
justified on an environmental basis. The environmental
benefits of reducing these leakages must be examined
further.

Additional efforts are necessary to achieve further
reductions in methane emissions from natural gas
systems. This includes the following:

. Mechanisms for transferring leak control
technologies to new users must be developed.
Targets of this technology transfer might be
systems which have been poorly maintained because
of size and/or financial constraints -- the
countries of Eastern Europe or smaller systems
within the U.S. are possible examples.

° Additional work on designing programs to encourage
comprehensive leak detection and mitigation needs
to be undertaken. The design of programs to
encourage economic replacement and/or upgrade of
old system components also needs to be
investigated.

. As venting of methane is an unknown and
potentially large source of methane emissions from
both oil and gas productions, flaring practices
and the potential to reduce these emissions must
be examined further.

. Fugitive methane from the well system itself
(prior to production measurement points) has not
been sufficiently investigated in light of new
technologies and may be significant. This is
especially true in basins of poorly consolidated
rock, and in old abandoned wells (gas and oil).

4. Natural Gas as a Transition Fuel

4.1

Fuel switching has the potential for significantly
reducing C02 emissions in the near and longer term and
could be used as one component of an integrated
strategy to reduce emissions of greenhouse gases. The
strategy would also include efforts to increase energy
efficiency and to decrease reliance on fossil fuels.

36



, Park Ridge, NJ: Noyes Data Corporation,
PP. 437-450.

Noble, J.J., T. Nunez-McNally, and B. Tansel (1988), "The Effects
of Mass Transfer on Landfill Stabilization Rates," in Proceedings
renc Landfi San
Olid W. , United Kingdom Department of Energy,
October 1988.

Pacey, John G. and Joseph P. DeGier (1986), "The Factors
Influencing Landfill Gas Production," in Energy From Landfill
Gas, proceedings of a conference jointly sponsored by the United
Kingdom Department of Energy and the United States Department of
Energy, pp. 51-59, October 1986.

Pettit, C.L. (1989), "Tip Fees Up More Than 30% in Annual NSWMA

Survey," Waste Age, March 1989, p. 101.
Pohland, F.P. and S.R. Harper (1986), Critical Review and Summary
of Leac! ean s_P: tion m Landfills, EPA/600/2-86/073,

U.S. EPA Hazardous Waste Engineering Laboratory, Cincinnati,
Ohio, August 1986.

Radian Corporation (1988), Memorandum from Y.C. McGuinn, Radian
Corporation, to Susan Thorneloe, U.S. Environmental Protection
Agency, "Use of a Landfill Gas Generation Model to Estimate voc
Emissions from Landfills," June 21, 1988.

Safley, M.L. and P.W. Westerman (1988), "Biogas Production from
Anaerobic Lagoons," Biological Wastes, Vol. 23, 1988, pp. 181-
193.

Van -Heuit, R.E., EMCON Associates (1986), "Estimating Landfill
Gas Yields," Proceedings of the 9th International Landfill Gas
Symposium, GRCDA, pp. 92-103.

Wilson, D.C., B.J.W. Manley, T. Nunez-McNally, S. Shaw, and H.S.
Tillotson (1988), "National assessment of Landfill Gas as a
Resource," in Proceedings of the International Conference on

Landfill Gas and Anaerobic Digestion of Solid Waste, United
Kingdom Department of Energy, pp. 369-379, October 1988.

Page C-18



2.2 Methane Stabilization

Although until recently the role of methane and the
possibility of reducing the rate of increase of methane in the
atmosphere have not been the subject of widespread discussion,
recent analyses presented at two IPCC workshops indicate that
methane control is possible and may be achieved at a low cost, if
not a profit. As a consequence of these emission control
opportunities, methane control may be a very cost-effective way
of limiting actual global warming in the next 30 to 60 years.

One reason why this is possible is that relatively small
reductions in methane emissions will lead to a halt in the
increase in methane concentrations relatively quickly. For
example, the observed rate of increase in atmospheric methane
concentrations discussed above indicates that methane in the
atmosphere is increasing at a rate of about 30 to 45 Tg per
year.” This result indicates that if the annual methane
emissions were reduced by about this amount and held constant,
methane concentrations would no longer increase, assuming that
the rate of methane destruction in the atmosphere also stayed
constant.

This estimate of the emissions reduction needed to stabilize
methane concentrations at approximately current levels is on the
order of about 10 to 15 percent of the total human-related
methane emissions. As a contrast, much larger emissions
reductions are required to halt the increasing concentrations of
the other trace gases, as follows:

Emissions Reduction

Trace Gas Needed to Halt Increase
Methane 10 - 15 percent
Carbon Dioxide 50 - 80 percent
Nitrous Oxide 80 - 85 percent
Chlorofluorocarbons 100 percent

To test the validity of this estimate of the emissions
reduction needed to stabilize methane concentrations, EPA's
Atmospheric Stabilization Framework (ASF) was used to estimate
the methane emissions reductions needed to stabilize atmospheric
concentrations. The ASF is a series of emissions and atmospheric

9 Bach 1 ppbv of increase in global atmospheric methane

equals about 2.77 Tg of methane in the atmosphere. Therefore,

because the global methane concentration is increasing at a rate
of about 10 to 16 ppbv per year, the global atmospheric abundance
of methane is increasing at a rate of about 28 to 45 Tg per year.

15



EXHIBIT 3

SOURCES OF METHANE EMISSIONS
10° Grams per Year

Annual
Emissions Range Comments Source
Animals 80 65 - 100 Livestock in developed Cicerone and
and developing Oremland
countries.
Animal Wastes 5 wr? Anaerobic decomposition IPCC
of organic wastes.
Wastewater NR 20 - 25 Anaerobic decomposition IPCC
of organic matter in the
waste water stream
Rice Paddies 110 60 - 170 Principally in Cicerone and
developing countries. Oremland
Coal Mining NR 30 - 50 Surface and (mostly) IPCC
sub-surface mining.
Oil/Gas Systems 45 25 - 50 Production, transmission Cicerone and
and distribution. Oremland
Landfills NR 25 - 40 Decay of organic wastes. IPCC
Biomass Burning 55 50 - 100 Forest clearing and Cicerone and
waste burning. Oremland
Natural Wetlands 115 100 - 200 Tundra, bogs, swamps, Cicerone and
alluvial formations. Oremland
Termites 40 10 - 100 Bacteria within termites Cicerone and
produce CH, as part of Oremland
the termite's digestive
process.
Oceans and 15 6-45 Cicerone and
Freshwaters Oremtand
Hydrates 5? 0 - 100 Potentially important Cicerone and
future source. Oremland
Total Emissions” 540 440 - 640 Well constrained. Cicerone and

Oremland

Biogeochemical Cycles, December 1988.

Sources: Cicerone and Oremland (1988), “Biogeochemical Aspects of Atmospheric Methane," Global

emissions.

data.

4 NR = not reported at the [PCC workshop

IPCC, December 1989 and April 1990 IPCC workshops on methane

b Total annual emissions of 540 Tg per year +100 Tg is well constrained based on observational
The point estimates of the individual source estimates presented here do not sum to 540 Tg.

10



FINDINGS

TABLE OF CONTENTS

1. INTRODUCTION . .. . - ee. ee ee ee

2. OVERVIEW OF METHANE'S CONTRIBUTION TO GLOBAL WARMING

2.1 Methane Concentrations Are Increasing. . .

2.2

2.3 Controlling Methane has Large Near-Term Benefits

Methane Stabilization. .....

3. OPPORTUNITIES FOR EMISSION REDUCTION .

4. FRAMEWORK FOR CONTROL... ..-+ +e e

4.1
4.2

5. FINDINGS

Approaches .......+4ee-.
Research NeedS ......+..--.

FOR OIL AND GAS SYSTEMS ...

6. FINDINGS FOR COAL MINES ......-..

7. FINDINGS FOR WASTE MANAGEMENT SYSTEMS .

8. FINDINGS FOR RICE CULTIVATION. ... .

9. FINDINGS FOR LIVESTOCK ....... .

REFERENCES . «1 6 e+ 6 ee ee ee we ee

APPENDICES
APPENDIX A OVERVIEW OF METHANE EMISSIONS .

A.1 Introduction .........-.

A.2 Emissions Sources ........

A.3 Emissions Reduction Opportunities

A.4 References .......-+-+46-4
APPENDIX B ENERGY-RELATED METHANE EMISSIONS

B.1 Oil and Gas Systems .......

B.2 Coal Mines .. 2... 1. eee ee

B.3 Combustion: Stationary and Mobile Sources

B.4 References ........24 26-4
APPENDIX C WASTE MANAGEMENT .......

C.1 Landfills ..........4..

C.2 Wastewater Treatment ......

C.3 Animal Wastes ..........

11

20

24

30

32

34

38

43

50

54



EXHIBIT D-5

ENERGY UTILIZATION IN RUMINANT ANIMALS

GROSS ENERGY

-
Foca Energy

OIGESTIALE ENERGY
(Reugrey comparacse © TON)

Energy METABOLIZABLE ENERGY

oN.
Heat neremers

NET ENERGY

Net Energy Mereenance Net Energy Proauceon

Source: Ensminger, M.E., The Stockman's Handbook, The
Interstate Printers & Publishers, Inc.: Danville, Illinois,

1983, p. 245.

Page D-12



be processed in a variety of ways, depending on the end use. CH,
produced by recovery systems can be used as a medium Btu fuel
(about 500 Btu per standard cubic foot, or scf) on-site or sold
to a nearby industrial customer, used to generate electricity to
sell to an electric utility, or upgraded to high Btu gas (about
950 Btu/scf or greater) and delivered to a natural gas pipeline
for blending with pipeline supplies. Revenues from sale of the
gas or of electricity generated from the gas can be profitable
for landfill owners, or can at least offset the costs of
complying with gas control regulations.

Gas recovery systems are not designed to capture all of the
gas generated at the landfill, but to focus on gas produced
deeper in the landfill, which is richer in CH, (Pohland, 1987).
According to industry experts (cited in Radian, 1988), from 30 to
65 percent of the generated gas is typically collected in
recovery systems. However, as discussed at the IPCC Workshop,
gas collection efficiencies of up to 90 percent can be achieved
at well-designed landfills equipped with bottom liners and
operated with leachate recirculation.

Alternatively, gas control systems have generally aimed at
minimizing subsurface lateral migration of gas, which can lead to
explosions in structures at considerable distances from the
landfill. These systems include (1) trenches or wells that vent
gas to the atmosphere passively, or (2) pumps that suction gas
from wells installed in the landfill, and either vent the gas to
the atmosphere or route it to a flare. Of these gas control
systems, only those that flare the collected gas have the
potential to reduce CH, emissions. In these systems, the amount
of generated gas intercepted by the collection system varies,
depending on the spacing between wells, the amount of suction
applied, the landfill design, and the surrounding soil type and

geography.

In addition to the reductions in methane emissions, steps
taken to reduce methane emissions from landfills provide other
significant environmental and safety benefits. Also, when
utilized as an energy source, the methane recovered from
landfills to reduce emissions may displace more carbon intensive
fuels, thereby also reducing carbon dioxide emissions.

Engineers, scientists, and landfill operators have made
major advances during the past two decades in understanding the
process of landfill gas generation, control, and recovery.
Further efforts in several research areas would help develop
effective strategies for controlling CH, emissions, including:

. evaluating the feasibility of enhancing CH, generation
on a practical and widespread scale (currently underway
in Europe) ;

Page C-8



APPENDICES

TABLE OF CONTENTS

APPENDIX A OVERVIEW OF METHANE EMISSIONS

PrP
PUNE

APPENDI

BDonno YP

x
1
2
3
4

APPENDI

loneononon-)

x
1
2
3
4

Introduction

Emissions Sources .......
Emissions Reduction Opportunities . .

References

B ENERGY-RELATED METHANE EMISSIONS .
Oil and Gas Systems ......

Coal Mines

Combustion:

References

Stationary and Mobile Sources

C WASTE MANAGEMENT ..... .

Landfills

Wastewater Treatment .....

Animal Wastes

References

D AGRICULTURAL SOURCES ....
Flooded Rice Cultivation ...
Managed Livestock .......
Biomass Burning ........

References

APPENDIX E LIST OF WORKSHOP ATTENDEES .



2.3 Controlling Methane has Large Near-Term Benefits

Large benefits can be derived by controlling methane
emissions and stabilizing atmospheric methane concentrations.
The ASF stabilization analysis presented in the previous section
also indicates that stabilizing methane concentrations will
reduce the radiative forcing added between 1990 and 2020 by about
20 percent. This reduction delays the equivalent buildup of all
greenhouse gases by about 10 years by this time.

Methane control represents an opportunity to slow the rate
of warming over the next 30 to 100 years. These types of
opportunities warrant attention because they could help to "buy
time" during which additional cost-effective techniques for
reducing carbon dioxide emissions and emissions of other
greenhouse gases can be identified, evaluated, and implemented.

The benefits of reducing emissions of a greenhouse gas, such
as methane, depend upon the global warming averted by that
reduction and upon.the speed at which the warming is averted.

The amount of warming averted by the reduction in emissions of a
unit of the greenhouse gas depends in turn on the potency of the
gas which may be characterized through the following factors:

. radiative absorbance;
. atmospheric lifetime;
. indirect effects on the concentrations of other

radiatively active gases; and

. past, present, and future emissions of other greenhouse
gases and their resulting concentrations.

The concept of the Global Warming Potential (GWP) attempts
to capture most of these considerations. A GWP is the ratio of
the warming caused by the emissions of a unit of a trace gas to
that caused by the emission of carbon dioxide at current
concentration levels. The definition of a GWP incorporates an
additional consideration over those listed above -- the ratio is
calculated over different time periods, comparing the warming of
the trace gas to that caused by carbon dioxide for a fixed number
of years following the emission.

The GWPs for methane which are calculated to reflect
different time horizons are all based on the following
information:

. Molecule for molecule, the instantaneous relative
radiative forcing of methane is 25 times that of carbon
dioxide or 70 times more gram for gram.

20



WORKSHOP ATTENDEES

WORKSHOP OF THE AGRICULTURE, FORESTRY,
AND OTHER HUMAN ACTIVITIES SUBGROUP (AFOS)

Y.P. Abrol

Division of Plant Physiology

Indian Agricultural Research Institute
New Delhi 110012

INDIA

Phone: 91-11-582-815

Telex: 3177161 IARI IN

Dilip Abuja

U.S. Environmental Protection Agency
401 M Street, SW (PM-221)
Washington, D.C. 20460

USA.

Phone: 202-382-6935

Ken Andrasko

U.S. Environmental Protection Agency
401 M Street, SW (PM-221)
Washington, D.C. 20460

USA.

Phone: 202-382-5603

Eric Arhenius

World Bank

1818 H Street, NW, Rm. S-5045
Washington, D.C. 20433
USA.

Phone: 202-473-3285

Lee Baldwin

University of California, Davis
Department of Animal Science
Davis, CA 95616

USA.

Phone: 916-752-1250

Fax 916-752-6363

E. Beauchamp

University of Guelph

Department of Land Resource Science
Guelph, Ontario N1G2W1

CANADA

David Beever

Institute of Grassland and Animal Production
Hurley, Maidenhead

Berkshire

UNITED KINGDOM

Phone: 062-882-3631

Fax: 062-882-3630

Lou Borghi

Clement Associates, Inc.
9300 Lee Highway

Fairfax, Virginia 22031-1207
USA.

Phone: 703-934-3255

Fax: 703-934-9740

Lex Bouwman

International Soil Reference
and Information Centre
P.O. Box 353

6700 A J Wageningen
THE NETHERLANDS
Phone: 31-8370-19063

Fax 31-8370-24460
Telex. ISOMUS NL

Susan Boyd

Concern

1794 Columbia Road, NW
Washington, D.C. 20009
USA.

Phone: 202-328-8160

Barbara Braatz

ICF Inc.

9300 Lee Highway
Fairfax, VA 22031-1207
USA.

Phone: 703-934-3603
Fax 703-934-9740

Page E-1



importance of international cooperation and the key research
steps needed to control methane emissions are identified.

Finally, the main body of the report concludes with the
findings from the IPCC workshops held on methane. These findings
were adopted by those attending the workshops.

Attached to the main body of the report are several
appendices. Appendix A presents an overview of methane
emissions. Appendices B, C, and D describe the emissions and

emissions reduction opportunities for:

. Appendix B: Energy-Related Methane Emissions: Oil and
Gas Systems; Coal Mines; and Combustion.

. Appendix C: Waste Management: Landfills;
Incineration; and Sewage Treatment.

. Appendix D: Agricultural Sources: Rice Cultivation;
Managed Livestock; Animal Wastes; and Biomass Burning.



Holzapfel-Pschorn, A. and W. Seiler (1986), "Methane Emission
During a Cultivation Period From an Italian Rice Paddy," Journal
of Geophysical Research, 91, pp. 11803-11814.

Holzapfel-Pschorn, A., R. Conrad, and W. Seiler (1986), "Effects
of Vegetation on the Emission of Methane from Submerged Rice

Paddy Soil," Plant and Soil, Vol. 92, pp. 223-233.
IRRI (1988), World Rice Statistics, 1987, The International Rice

Research Institute, Los Banos, Philippines.

Khalil, M.A.K., R.A. Rasmussen, and M.X. Wang (1989), as
presented by M.R. Riches, "Flux of Methane from Rice Paddies in
China," Proceedings of the Workshop on Greenhouse Gas Emissions
from Agricultural Systems of the IPCC Response Strategies Working
Group, December 12-14.

Minami, K. (1989), “Effects of Agricultural Management on Methane
Emissions from Rice Paddies," Proceedings of the Workshop on
Greenhouse Gas Emissions from Agricultural Systems of the IPCC
Response Strategies Working Group, December 12-14.

Neue, H.U. and W.W. Scharpenseel (1984), Gaseous products of
decomposition of organic matter in submerged soils, In: Organic

, International Rice Research Institute, Los
Banos, Philippines, pp. 311-328.

Moe, P.W. and H.F. Tyrrell (1979), "Methane Production in Dairy
Cows," Journal of Dairy Science, Vol 62, pp. 1583-1586.

Schutz, H., A. Holzapfel-Pschorn, R. Conrad, H. Rennenberg, and
W. Seiler (1989), "A Three Year Continuous Record on the
Influence of Daytime, Season and Fertilizer Treatment on Methane
Emissin Rates from an Italian Rice Paddy Field," Journal of

Geophysical Research.

Sebacher, D.I., R.C. Harriss, K.B. Bartlett, S.M. Sebacher, and
S.S. Grice (1986), "Atmospheric Methane Sources: Alaskan Tundra
Bogs, an Alpine Fen, and a Subarctic Boreal Marsh," Tellus, Vol.
38B, p. 1-10.

Seiler, W. (1984), "Contribution of Biological Processes to the
Global Budget of CH, in the Atmosphere." In: Klug and C. Reddy
(eds.), Per: ives Microbial Ecology, M. American
Society for Microbiology, Washington, D.C. pp. 468-477.

Seiler W., A. Holzapfel-Pschorn, R. Conrad, and D. Scharffe
(1984), "Methane Emissions from Rice Paddies," Journal of

Atmospheric Chemistry, Vol. 1, pp. 241-268.

Page 0-21



by 90 percent in new landfills, and existing commercial
operations show that these systems are profitable in
may cases.

: Pre-mining degasification using vertical
wells can profitably reduce emissions from underground
mines by up to 50 percent in some mines, as shown by
existing enterprises. It was also suggested that
emissions can be reduced further by using mine
ventilation air that contains less than one percent
methane as combustion air in gas fired turbines.

Oil and natural gas systems: Improved handling of

casing gas during oil production will reduce venting
and flaring emissions. It was suggested that emissions
from gas transmission in the USSR could be reduced by
improving the USSR gas transmission facilities. Other
options for unusually leaky systems may also be
possible.

Livestock: Strategic diet supplementation with
locally-produced resources and other animal management
practices can profitably reduce emissions by 25 to 75
percent per unit of product.

Animal wastes and wastewater treatment: Methane
recovery systems can profitably capture 50 to 90
percent of the methane emitted by anaerobic waste
management lagoons, as demonstrated by current systems.
Such lagoons account for one-third of total emissions
from animal wastes, and may account for the majority of
emissions from wastewater treatment.

Rice cultivation: -Over the long term emissions can
likely be reduced by 10 to 30 percent by an integrated
management approach to irrigation, fertilizer
application, and cultivar selection.

Biomass burning: Methane emission reductions can be
achieved through fire management programs and
encouraging the use of alternative agricultural
practices.

Depending on the extent to which each of the emissions reduction
opportunities is undertaken, the emissions reduction realized may
be adequate for stabilizing and possibly even reducing methane
concentrations below current levels.

Exhibit 9 presents an estimate of the potential magnitude of
emissions reductions that can be achieved. Based on the
information presented at the IPCC Workshops, it appears to be
technically feasible to reduce methane emissions on the order of

25





Gob Wells. Underground longwall mines (and some room and
pillar mines) can release large amounts of CH, from the
fractured gob area behind the working longwall face. In
cases where gas liberation is significant, wells can be
drilled from the surface to drain the CH, from the gob area
and prevent it from entering the mine workings. Generally,
these wells are drilled to a point 2 to 15 meters above the
mined seam prior to the mining of the longwall panel. As
mining advances under the gob well, the CH,-containing
strata around the well will begin to fracture. The CH,
emitted from this fractured strata flows into the gob well
(which often operates on a vacuum) and then to the surface.
CH, production rates associated with gob wells can be very
high (over 1 million cubic feet per day) immediately
following the fracturing of the strata, and then decrease to
levels around 100,000 cubic feet per day.

The quality of gas produced by gob wells, in terms of its
CH, concentration, is variable and depends on the strength
of the vacuum applied to the gob well and the degree to
which mine air is extracted along with the CH, in the gob.
Maintaining a high quality product requires precise
monitoring and adjustment and an ability to integrate gas
production and mining operations.

vertical Wells. The optimum technique for controlling CH,
emissions from a mine safety standpoint is to employ
vertical degasification wells to pre-drain the CH, from the
coal and surrounding strata before mining operations begin.
These wells are similar to conventional oil and gas wells
and are drilled into the coal seam before mine development.
Many of these wells typically produce large quantities of
water and small quantities of gas during their first several
months of production. As the water in the coal seam is
removed, however, the pressure on the coal seam is lowered
and the CH, begins to desorb, thereby increasing the CH,
production rate. Typical production rates for these wells
are on the order of 100,000 to 200,000 cubic feet per day
over their five to ten year lifetime.

Pre-drainage of CH, using vertical wells is a very effective
method of reducing the CH, content of coal beds and thus the
methane emissions associated with the eventual coal mining
operation. These wells have not been widely used in the
coal mining industry, due largely to their relatively high
up-front costs and the difficulties associated with
stimulating them and producing gas. Several conventional
oil and gas operators are currently producing natural gas
from coal seams using these wells in operations that are
independent of coal mining activities.

Page 8-12



D.4 References

Baldwin, R.L. and M.J. Allison (1983), "Rumen Metabolism,"
° a. cie: , Vol. 57, pp. 461-477.

Blaxter, K.L. and J.L. Clapperton (1965), "Prediction of the
Amount of Methane Produced by Ruminants," British Journal of
Nutrition, Vol. 19, pp. 511-522.

Bouwman, L. (1989), Proceedings of the Workshop on Greenhouse Gas
Emissions from Agricultural Systems of the IPCC Response
Strategies Working Group, December 12-14.

Cicerone, R.J. and R.S. Oremland (1988), "Biogeochemical Aspects

of Atmospheric Methane," Global Biogeochemical Cycles, Vol. 2,
No. 4, 299-327, December.

Cicerone, Ralph J. and J.D. Shetter (1981), "Sources of
Atmospheric Methane: Measurements in Rice Paddies and a

Discussion," Journal of Geophysical Research, Vol. 86, pp. 7203-
7209.

Crutzen, P.J., L.E. Heidt, J.P. Krasnec, W.H. Pollock, and W.
Seiler (1979), "Biomass Burning as a Source of Atmospheric Gases
CO,H2, N20, NO, Ch3Cl, and COS,: Nature, Vol. 282, pp.253-256.

Crutzen, P.J., I. Aselmann and W. Seiler (1986), "Methane
Production by Domestic Animals, Wild Ruminants, Other Herbivorous
Fauna, and Humans," Tellus, 38B, pp. 271-284.

Dalrymple, D. (1986), "Development and Spread of High-yielding
Rice Varieties in Developing Countries," Bureau for Science and
Technology, Agency for International Development, Washington,
D.c.

Delwiche, C. (1988), "Methane Emission Rates," Presented at U.S.
EPA Workshop on Agriculture and Climate Change, Washington, D.C.,
February 29-March 1.

Ehhalt, D.H. (1974), "The Atmospheric Cycle of Methane," Tellus,
Vol. 26, pp. 58-70.

Ehhalt, D.H. and U. Schmidt (1978), "Sources and Sinks of
Atmospheric Methane," Pageoph., vol. 116, p. 452-464.

Ensminger, M.E. (1983), The Stockman's Handbook, The Interstate
Printers & Publishers, Inc.: Danville, Illinois.

Page 0-20



The emissions estimates developed by PSI are shown in
Exhibit B-2 for three main parts of natural gas systems:
(1) withdrawal and field separation; (2) gathering, processing,
and transmission; and (3) distribution. For each of these three
segments, PSI estimated emissions associated with normal
operations, routine maintenance, and upsets/mishaps.“ The
largest sources of emissions appear to be the following:

. Upsets/mishaps during withdrawal and field separation.
The emissions from this segment are comprised primarily
of gas that is vented during withdrawal and field
separation. The estimates of the amounts of gas that
are vented are very uncertain because little data are
available for estimating this quantity. PSI indicates
that these emissions could be much larger or smaller.
Additionally, a significant portion of these emissions
may be related to oil production as opposed to natural
gas production.

. Normal operations during gathering, processing, and
transmission. The emissions from this segment are
primarily comprised of emissions associated with the
operation of pneumatic instruments and from leaks at
gas processing plants (i.e., fugitive emissions). The
emissions from pneumatic instruments are based on, the
PG&E UFG study results; the use of such instruments in
the U.S. and the emissions per instrument should be
examined to improve this component of the estimate.
The leaks from gas plants are based on: (1) emissions
rates for components such as valves and flanges
published by the American Petroleum Institute in 1980;
and (2) counts of components in a typical gas plant.
This component of the emissions estimate is considered
to be reasonably precise.

. Routine maintenance at transmission facilities. These
emissions are primarily related to pipeline purge and
blowdown activities. Consequently, the emissions will
vary with operating practices. This estimate, based on
the PG&E UFG study results, is considered to be
reasonably precise.

2 These categories of emissions are defined as: Normal

Operations: chronic emissions from the day to day operation of
the facility (e.g., leakage around valves); Routine Maintenance:
controlled emissions from activities regularly performed on the
facility (e.g., blowing and purging); Upset Conditions/Mishaps:
episodic emissions due to unplanned events in the proper
operation of a facility (e.g., emissions through relief valves)
and episodic emissions from abnormal events arising from outside
the system (e.g., dig-ins).

Page B-S



|

2. OVERVIEW OF METHANE'S CONTRIBUTION TO GLOBAL WARMING

Methane is an important greenhouse gas, accounting for about
15 percent of the "radiative forcing" added to the atmosphere in
the 1980s (see Exhibit 1). The radiative forcing is a measure of
the manner in which the radiative properties of the atmosphere
are changing in response to emissions of greenhouse gases.

Methane levels are increasing substantially as demonstrated
by comprehensive global measurements of atmospheric methane
concentrations. These measurements show that over the past 300
years atmospheric methane concentrations have more than doubled,
and that its concentration continues to increase by about 1
percent (10 to 16 ppbv’) per year (WMO, 1990). Exhibit 2
displays recent measurements of global atmospheric methane
concentrations.

These measured increases in methane concentrations are
highly correlated with increases in global population and human-
related activities that release methane to the atmosphere. The
major human-related sources of methane emissions include:

. rice cultivation;

. livestock and other animals (including animal wastes) ;
. biomass burning;

° coal mining;

. oil and gas systems; and

. landfills.

The approximate levels of emissions from each of these
sources are summarized in Exhibit 3 and described more fully in
Appendix A. These human-related methane sources account for
about 70 percent of total methane emissions from all sources.

As shown in the exhibit, the total global emissions of
methane from all sources are estimated at about 540 Tg per year.
Despite uncertainties in each of the major sources of emissions,
the total global emissions are well constrained by observational

5

* parts per billion by volume.

5 Tg = 1 teragram = 10 grams = 10° kilograms = 1 million

metric tons.



degasification systems are viewed simply as a supplement to the
ventilation system. There are four basic degasification
techniques available:

ventilation. The main technique for controlling CH,
concentration in coal mines is ventilation, and it is used
universally in underground coal mines. U.S. regulations
require that all coal mines be ventilated by continuously
operating mechanical fans which circulate fresh air across
the actively mined coal face. As a result of these
ventilation requirements, large quantities of CH, are vented
to the atmosphere in the ventilation air.

Currently, there are limited uses for the CH, in ventilation
air, which is vented at concentrations of less than 1
percent. It is possible that some of this ventilation air
could be used in mine-site powerplant boilers as combustion
air. Given the large amounts of air circulated through the
mine, however, it is unlikely that on-site generation could
use more than a fraction of this air. Another possibility
for capturing this CH, would be to separate it from the
ventilation air. Various techniques for separating the CH,
and producing a more concentrated product have been
considered, but none are economic under current market
conditions.

Horizontal and Cross-Measure Boreholes. This degasification
measure consists of drilling boreholes from within the mine
workings into the unmined areas of the coal seam being mined
or the adjacent strata above or below the mined coal sean.
These boreholes are typically tens of meters to hundreds of
meters in length and several hundred boreholes may be
drilled to control emissions in a single mine. Once
drilled, these boreholes are often connected to an in-mine
vacuum piping system which prevents the release of this CH,
into the mine workings and transports it to the surface.
This piping system reduces CH, emissions into the mine
workings when the coal is eventually mined. Alternatively,
long horizontal boreholes, roughly 1000 ft in length, have
been drilled which are connected to an undergroud pipeline
which is in turn joined to a vetical borehole that
terminates at the surface. Flow from these holes is aided
only by the lighter-than-air buoyancy of methane.

Many underground mines, both in the United States and
abroad, use horizontal and cross~measure boreholes to
supplement their ventilation system. In the United States,
horizontal boreholes typically produce pipeline quality gas
(with CH, concentrations over 95 percent).

Page B-11



B.4 References

A.D. Little (1989), "Methane Emissions from the Oil and Gas
Production Industries," Final report to Ruhrgas A.G., July 1989.

Alphatania Group, The (1989), "Methane Leakage from Natural Gas
Operation," July and August 1989.

Bolle, H.-J., W. Seiler and B. Bolin (1986), "Other Greenhouse
Gases and Aerosols: Assessing Their Role for Atmospheric
Radiative Transfer." In: Bolin, B., B.R. Doos, B. Warrick and
D. Jager (eds.), The Greenhouse ect C tic

Ecosystems, New York, John Wiley & Sons, pp. 157-203.

Cicerone, R.J. and R.S. Oremland (1988), "Biogeochemical Aspects

of Atmospheric Methane," Global Biogeochemical Cycles, Vol. 2,
No. 4, 299-327, December 1988.

Crutzen, P.J., (1987) "Role of the Tropics in Atmospheric

Chemistry." In: Dickinson, R. (ed.), Geophysiology of Amazonia,
New York, Wiley & Sons, pp. 107-132.

ICF Resources (1990), Methane Emissions to the Atmosphere from
Coal Mining, draft report prepared for the U.S. Environmental

Protection Agency Office of Air and Radiation by ICF Resources
Incorporated.

Marland, G. and R.M. Rotty (1984), "Carbon Dioxide Emissions from
Fossil Fuels: A Procedure for Estimation and Results for 1950-
1982," Tellus, Vol. 36B, 1984, pp. 232-261.

PSI (1989), “Annual Methane Emission Estimate of the Natural Gas
and Petroleum Systems in the United States," prepared for the
U.S. EPA by Pipeline Systems Incorporated.

Radian Corporation (1987), "Comparing the Impact of Different
Transportation Fuels on the Greenhouse Effect," prepared for the
California Energy Commission by Acurex Corporation, March 1989.

Sheppard, J.C., H. Westberg, J.F. Hopper, and K. Ganesan (1982),
"Inventory of Global Methane Sources and Their Production Rates,"

Journal of Geophysical Research, Vol. 87, pp. 1305-1312.

Unnasch, S. and C.B. Moyer (1989), "Comparing the Impact of
Different Transportation Fuels on the Greenhouse Effect,"
prepared for the California Energy Commission by Acurex
Corporation, March 1989.

Wernstedt, G. and G. Fernback (1989), "Releases of Methane from
Natural Gas Activity in Sweden," prepared for Swedegas by Thorell
+ VBB Energikonsulter AB, August 29, 1989.

Page B-16



. Asia and Far East: 8 Tg.

Due to a lack of data and measurements, these emissions
estimates are uncertain. In particular, the assumption that 11
percent of the CH, potential is realized from the wastes of
grazing cattle is very uncertain. Because of the large number of
cattle that are grazing, this assumption is an important factor
that influences the overall emissions estimate.

Emissions Reductions

The primary technique available for reducing CH, emissions
discussed to date is to modify the manner in which wastes are
managed from large concentrations of animals. Candidates for
reducing emissions would be:

. Swine and Poultry Facilities: Swine and poultry are
primarily raised in large concentrations in confined

structures throughout the world. The CH, from these
wastes could be recovered and used as fuel without
adversely affecting the fertilizer value of the manure.
A hog farm in the U.S. has an operating system that
recovers CH, and produces electricity.

. Dairies and Feedlots: Large dairies and feedlots that
treat wastes in lagoons or in drylots present an
excellent opportunity for recovering CH, emissions.
Demonstration projects are required to investigate the
preferred method of handling solids that are not broken
down anaerobically.

. Digestors: Small low-cost anaerobic digestors are
being developed to provide fuel to homes with a small
number of livestock. The principal objective is to
provide a reliable fuel source because wood is becoming
scarce in some locations. This technology could also
be promoted as a means of reducing CH, emissions from
animal wastes.

Opportunities have not yet been identified for reducing CH,
emissions from the wastes of grazing animals.

Page C-16



5.

under certain conditions, the systems are economic
to implement in their own right.

OTHER KEY RESEARCH NEEDS

5.1

Estimates of global CH, emissions from livestock should
be improved by enumerating the major livestock
managements systems (including animal waste management
systems) and performing more realistic assessments of
the major systems that drive global emissions. These
assessments should reflect the stages in animal growth
and production and prevailing levels of feed intake.

Techniques for taking field measurements of CH,
emissions from animal systems should be developed and
applied. Such techniques will be useful for verifying
estimates of emissions and validating the effectiveness
of emissions reduction techniques in the field.
Approaches that should be pursued include:

- Exploring direct and indirect methods of assessing
CH, emissions for field applications.

INSTITUTIONAL ISSUES

6.1

Reducing emissions from livestock is a particularly
attractive option because it usually is accompanied or
accomplished by improved animal productivity.

In designing interventions to reduce CH, emissions from
livestock, consideration should be given to the impacts
of these interventions on other greenhouse gases and
other environmental and social areas of interest.

The implementation of technologies to reduce CH,
emissions will, in general, succeed only if induced by:
incentives, technology transfer, and/or the provision
of adequate financing. A mandatory emissions
limitation is unlikely to be successful in reducing
emissions.

It is essential that countries maintain or build up the
scientific infrastructure required to greatly increase
levels of research to find solutions for limiting CH,
emissions from livestock.

Current funding specifically to investigate, develop,

test, and implement CH, reduction technologies and
programs does not exist.

61



APPENDIX A

OVERVIEW OF METHANE EMISSIONS

A.1 Introduction

The observation that methane (CH,) is increasing in the
atmosphere has sparked considerable interest in assessing the
sources and sinks of CH, emissions and the factors that are
contributing to the observed increase. Several comprehensive
reviews of the atmospheric balance of CH, have been published,
including: Cicerone and Oremland (1988), Bingemar and Crutzen
(1987), Bolle, Seiler, and Bolin (1986), WMO (1986), Blake
(1984), and Ehhalt (1974). These studies, in turn, draw ona
wide range of anaiyses of specific emissions sources and analyses
of CH, destruction processes.

As described by Cicerone and Oremland, estimates of total
annual global CH, emissions are constrained by available pieces
of data to fall within a fairly narrow range. Based on direct
measurements, the total atmospheric burden of CH, can reliably be
estimated at 4,800 Tg.! Similarly, during the early 1980s the
annual increase of atmospheric CH, can be estimated, based on
direct measurement, to be about 40 to 46 Tg per year. Finally,
based on independent analyses of methyl chloroform (CH;CC1,), the
atmospheric lifetime of CH, is estimated at 9.6 years, with a
range of 8.1 to 11.8 years.

1 Steele (1987); 1 Tg = 1 teragram = 10% grams = 10°

kilograms = 1 million metric tons.
2 wMo (1990) summarizes more recent estimates of the rate

of increase of atmospheric methane as ranging from 10 to 16 ppbv

(parts per billion by volume) per year. This range is about

30 to 45 Tg per year, which is a larger than the range reported

by Cicerone and Oremland (1988).

3 Based on analyses of emissions and atmospheric levels of
CH;CCl, over time, the rate of removal of CH; Cccl, from the
atmosphere by the hydroxyl radical (OH) has Deen estimated (see
Prinn et al. (1987)). Because the major mechanism by which CH,
is destroyed in the atmosphere is also by reaction with OH, the
atmospheric lifetime for CH, can be estimated from the
atmospheric lifetime for cH, ccl, and the relative reactivity of
the two compounds with OH. "Atmospheric lifetime" refers to the

(continued...)

Page A-1



EXHIBIT 4
BUSINESS AS USUAL SCENARIO FOR METHANE EMISSIONS

1100

1000 +

900 +

800 4

700 +

600 +

500 7

AKNQ4 OZO—-GHHO—-EM mz>rTamzs

400 T + T T T

1980 2000 2020 2040 2060 2080 2100
YEAR

Source: IPCC Working Group 1 Science Assessment Report

6(...continued)
(1983); Fraser et al. (1981); Khalil and Rasmussen (1982), and
Khalil and Rasmussen (1990), as well as various updates and
extensions of these estimates.

12



J. David Mobley

Us EPA

air and Energy Engineering
Research Lab MD-62
Research Triangle Park, NC
27722

Tel: 919-541-2612
Fax: 919-541-2382

Mark A. Moser

Resource Conservation Ngt.,
Inc.

PO Box 4715

Berkeley, CA 94704

Tel: 415-658-4466
Fax: 415-658-2729

John J. Mulhern

Mine Safety & Health Admin.
Dept. of Labor

Technical support

4015 Wilson Blvd.
Arlington, VA 22202

Tel: 703-235-1590

Sidney 0. Newman
U.s. Bureau of Mines
2401 EB Street, NW
Washington, DC 20241

Tel: 202-634-9892

R. J. Nielen

Netherlands Organization for
Applied scietnfic Research
TNO

Dept. of Environmental
Technology

PO Box 342

7300 AH Apeldoarn

The Netherlands

Tel: 31 55493493
Pax: 31 55419837
Telex: 36395 tnoap nl

Shuzo Nishioka
National Institute for
Environmental studies
16-2, Onogawa, Tsukuba
305 Japan

Tel: 81-298-51-6111 ext. 309
Fax: 81-298-51-4732

Dr. Jurgen Orlich

Head of Hazardous Waste Div.
Federal Environmental Agency
Bismarck Plats 1

D-1000 Berlin 33

Fed. Rep. of Germany

Tel: 30-8903-2807
Telex: 183 756 UBAD

John G. Pacey
Emcon Associates
1921 Ringwood Ave.
San Jose, CA 95131

Tel: 408-453-7300

Joao Luiz Pereira-Pinto
Science & Technology section
Brazilian Embassy

3006 Massachusetts Ave., NW
Washington, DC 20008

Tel: 202-745-2750
Fax: 202- 745-2728

Clyde Perry

Washington Gas Light Company
6801 Industrial Rd.
Springfield, VA 22151

Tel: 703-750-4851
Fax: 703-750-7570

Page E-18



Although these technologies have been demonstrated,
additional research is necessary to determine how best to
maximize CH, production from these systems. The amount of CH,
actually recovered by these systems will depend on several
factors, including:

. Te ola Em : Research is necessary to determine the
optimal combination of technologies and the timing of their
installation. The issues considered should include the cost
of gas recovery, the amount of gas produced, any geologic
factors that influence technology selection, and mining
needs.

. Well Spacing: Research is necessary to determine the
optimal well spacing depending on geologic and other site
characteristics. If wells are too far apart, gas recovery
will take too long, while if wells are too close together
the expense associated with gas recovery may be too high.

. Geologic Characteristics: Research is needed to explore the

relationship between a site's geologic characteristics and
the need for and use of degasification technologies. The
applicability of various degasification technologies, as
well as the CH, content of the coal and surrounding strata,
are highly influenced by geologic conditions.

Utilization

There are many options for using CH, recovered from coal
mines. In some cases, coal companies are selling high quality
gas (95 percent CH,) to pipeline companies. Recovered CH, can
also be used to generate power either at the mine site or at
nearby powerplants. Turbines and combustion engines have been
developed which can use medium or high quality CH, (roughly above
30 percent CH,). Further, recovered CH, could be "co-fired"
along with coal in coal-fired boilers.

The recovered CH, is not widely used, however, and in many
cases it is vented to’ the atmosphere. Additional work in this
area should focus on expanding the use of cost-effective
utilization. This includes work on

. maximizing CH, recovery using degasification
technologies;

. encouraging the wider application of utilization
technologies;

. integrating the use of mine degasification and CH,

utilization technologies; and



Methane Emissions Tg per Year

EXHIBIT 6

METHANE EMISSIONS SCENARIOS AND METHANE STABILIZATION

1,100

1,000 +

RCW Scenario

RCW and SCW Scenarios with Stabilization Emissions

Two base scenarios of methane emissions were
analyzed: Rapidly Changing World (RCW) and Slowly
Changing World (SCW) from EPA (1989). These
scenarios represent a wide range of potential
future emissions for greenhouse gases.

The methane emissions needed to stabilize
concentrations are labeled as the "Stabilization
Emissions" for each scenario. As shown, emissions
must be reduced by about 30 Tg by the year 2000 in
order to stabilize concentrations. Subsequent
growth in emissions must also be restrained over
the long-term.

17



better understand methane emissions from wastewater
treatment systems, research is required to:

. Collect available data on wastewater management
practices throughout the world.

. Identify those areas and facility types that are
potentially important sources of methane
emissions. Candidate facility types include food
processing facilities such as: fruit and
vegetable processing; meat packing; sugar
production; creameries; and distilleries.

. Characterize and measure the emissions at the
important facilities.

2.3 Animal Wastes. While animal wastes are potentially a
globally significant source of methane emissions, a
lack of field data leaves uncertainties as to the
quantity of emissions. To improve the understanding of
these emissions research is required to:

. improve current enumerations of animal numbers and
waste quantities managed with various practices;

. develop methane emissions measurement techniques;

. measure methane emissions from those situations

that appear to be most important from an overall
emissions perspective; and

. assess changes in methane emissions over time as
management practices change.

The measurements of methane emissions from animal
wastes must consider local and seasonal factors that
affect emissions.

3. Technical Potential for Reducing Emissions

3.1 Landfills. Technologies and practices exist to reduce
methane emissions from landfills by collecting and
flaring or utilizing the methane generated in the
landfill. In many circumstances these technologies and
practices appear to be cost effective. Use of these
technologies and practices is believed to reduce
methane emissions by 40 to 70 percent at existing
landfills. In new landfills, it is believed that
methane emissions can be reduced by 70 to 95 percent
using currently available technologies and practices.
Steps taken to reduce methane emissions from landfills

46



(ICF Resources, 1990). CH, emissions from this source are
expected to increase in the future, moreover, as shallower coal
reserves are depleted and the proportion and depth of underground
coal mining increases. It is estimated that by the year 2000,
CH, emissions from this source could reach 70 to 85 teragrams.

The majority of methane emissions from coal mining are
estimated to be in five countries: the United States; the
People's Republic of China; the Soviet Union; Poland; and South
Africa. The People' s Republic of China is estimated to have the
largest CH, emissions from this source, with about one-third of
global emissions. The Soviet Union, the United States, and
Poland, in addition to China, are estimated to account for almost
three-quarters of world-wide CH, emissions from this source.

Previous studies have estimated that CH, emissions from coal
mining range from 8 to 45 teragrams. The wide range in estimates
results from differing methodologies and input data used by these
studies, primarily in terms of coal production, coal type and the
average CH, emissions of the mined coal. None of the previous
studies have developed a methodology for relating the coal seam
CH, content to the CH, emissions resulting from mining
activities. In addition, some of these previous studies have
relied on historic levels of coal production, have estimated CH,
emissions from hard coal (bituminous and anthracite) production’
only, and have used undocumented estimates of average CH,
emissions associated with coal production.

The most accurate approach toward quantifying CH, emissions
from coal mines would be to measure actual CH, emissions at
underground and surface coal mines. Given the number of mines
involved, however, such an approach is not practical. Instead,
recent studies have begun developing relationships between the
CH, content of the mined coal and the CH, emissions measured from
the mine. Many geologic and other factors can influence the
actual CH, emissions from a particular coal mine, however, and
thus this’ approach is very approximate.

Furthermore, data on coal CH, contents, CH, emissions and
even coal production are not readily available for some
countries. Thus, recent studies have relied heavily on U.S. data
and have extrapolated U.S. CH, emission estimates to other
countries. The preliminary estimates generated by this approach
can be useful to policy makers and researchers in identifying
those countries with potentially significant CH, emissions from
this source and enables them to allocate scarce resource funds
more effectively. However, until more data are collected the
estimates prepared to date should be considered preliminary and
approximate.

Page B-9



emissions to ensure stabilization of methane concentrations can
also likely be achieved.

In order to realize the emissions reductions that have been
identified, the emissions reduction techniques need to be
evaluated fully, and the barriers that may inhibit their
implementation need to be identified. For example, while it may
be profitable to recover and utilize methane that would have been
emitted from coal mines, institutional questions of ownership and
constraints on receiving fair prices for gas or electricity may
block implementation. Similarly, strategic supplementation of
livestock may be economically profitable, but lack of capital and
infrastructure may block implementation. Efforts to realize
technologically possible and economically rational reductions
must recognize and overcome barriers and constraints to
implementation. In this context international approaches for
promoting the steps need to reduce emissions are discussed next.

29





CH, yield can be expressed as the CH, created as a percentage of
any of these energy quantities. Some previous estimates express
the CH, yield as a percentage of the gross energy consumed,
although there are indications that expressing the CH, yield as a
percentage of the digestible energy consumed may be preferred.
Most published CH, yield estimates for ruminants fall in the
range of 4 to 9 percent of gross energy intake.

Using an estimate of the CH, yield for an animal, its total
annual CH, emissions can be estimated by multiplying its relevant
annual energy intake by the appropriate percentage (e. g. 6
percent) and then converting the energy value (e.g. in megajoules
or MJ) to a mass basis (e.g. kilograms). For example, if a cow
consumes 60,000 MJ per year in gross energy and has a CH, yield
of 6 percent of gross energy, then total CH, emissions would be
equal to 3,600 MJ, or about 65 kilograms.°

Crutzen et al. (1986) have performed the most comprehensive
assessment of CH, emissions from ruminant animals to date and
estimate CH, emissions of 71 Tg/yr from ruminant animals.

Exhibit D-6 lists their estimates. Various deficiencies in these
estimates have been identified, particularly relating to the
emissions estimates from animals grazing on poor quality forages
and fed poor quality crop residues. Actual emissions from
animals in these situations may be much lower or higher.
Additionally, some have pointed out that the estimates by Crutzen
et al. do not reflect variations associated with different stages
of animal growth and development.

Analyses that would be useful for improving the estimates of
CH, emissions from livestock include:

. Charac ize t! nimal ation. The manner in
which an animal population is managed and the type of
feed they consume influences the overall level of CH,
emissions. Data are required that describe the
management of animals along dimensions that influence
CH, emissions. These analyses should focus on those
populations of animals that are good candidates for
emissions reduction.

: CH, yields associated with poor quality forages and
crop residues. Little data are available to describe
the CH, yields associated with animals consuming poor

5 of note is that the methane yield varies with the
quantity and quality of food energy consumed. Because feed
consumption by ruminant animals often varies throughout the year,
it will likely be preferred to estimate feed intakes and methane
emissions at least seasonally.

Page 0-13



EXHIBIT 5

BUSINESS AS USUAL SCENARIO FOR METHANE CONCENTRATIONS

4000

3500 4

3000 +

2500 +

2000 +

1500 4

cv0U Z2Z0O-A>DAZMONZON

1000 T T T T T
1980 2000 2020 2040 2060 2080 2100

YEAR

Source: IPCC Working Group 1 Science Assessment Report

13



4.

KEY RESEARCH NEEDED ON SPECIFIC EMISSIONS-REDUCTION

OPPORTUNITIES
4.1 Strategic supplementation of extensively managed

cattle. Large populations of cattle are consuming
forages of variable quality (particularly seasonally)
under grazing conditions. The relative productivity of
these animals (e.g., in terms of reproductive
efficiency) is low in some cases. By providing
strategic supplementation of nutrients to these
animals, CH, emissions could be reduced by: (1)
providing a better balance in the rumen, which would
reduce CH, emissions per amount of feed consumed; and
(2) increasing efficiency and productivity such that
given levels of production could be achieved with
smaller animal numbers.

-- The size of the animal population that could
benefit from this supplementation must be
estimated. It is expected that in some areas, the
applicable population may be a significant portion
of the total animal population.

-- The types of supplementation appropriate for each
area must be defined.

-- Techniques for delivering the technology
efficiently must be identified. Avenues to
explore include: range improvement; nutrient feed
blocks; bolus.

-- The monetary and energy costs of producing and
distributing the technology must be estimated and
balanced against improvements in animal
performance.

-- The reductions in CH, emissions and improvements
in animal performance (that lead to overall
system-wide CH, emissions reductions) must be
documented and’ validated under field conditions.

Diet modifications for i ve imals. A
significant literature of experimental data from whole
animal calorimetry experiments demonstrates that CH,
emissions vary under different diets. Both increasing
the intake of the animals and modifying the composition
of the diet can reduce CH, emissions per unit of
product. Other feed inputs also appear to have
promising impacts on CH, emissions levels (e.g., whole
cotton seeds or polyunsaturated fats). Modifying

57



integrated, interdisciplinary projects which focus on process
related factors and which will allow for valid extrapolation.
Research is needed on the following aspects:

. biogeochemistry of methanogenesis in flooded rice
fields including CH, production, CH, oxidation, and
methanogenesis regulating factors;

. factors affecting CH, fluxes from flooded rice fields
such as climate, soit and water, cultivars, fertilizer
application, and cultural practices;

. variations in CH, fluxes between sites, seasonally, and
diurnally;
. effects of techniques to reduce CH, emissions on

emissions of nitrous oxide; and

. field level measurement techniques to assess spatial
variability and simulation models to synthesize the
process and field level data.

Technologies and practices for reducing emissions from
flooded rice fields need to be developed, demonstrated and
assessed, including an evaluation of the costs and benefits. To
realize the full potential of the research, existing and possible
agricultural policies regarding rice production need to be
examined. This includes alternative economic policies such as
subsidies, taxes, pricing and trade barriers; cultural practices;
technology transfer measures; education and information programs;
and international financial assistance measures.

D.2 Managed Livestock
issions

Among livestock, ruminant animals produce significant
quantities of CH, as part of their normal digestive processes.
The rumen, a large fore-stomach, provides the opportunity for CH,
to be created within the animal. Within the rumen over 200
species and types of microorganisms have been identified,
although a smaller number (10 to 20 species) are thought to play
an important role in rumen digestive processes (Baldwin and
Allison, 1983). Rumen methanogenic bacteria are the source of
CH, produced within ruminant animals.

Rumen methanogenic bacteria are generally a very small
fraction of the total population of microorganisms in the rumen.
Although they can convert acetate (a fermentation product
produced in the rumen) to CH, and carbon dioxide (CO,), this

Page 0-10



EXHIBIT C-2

POTENTIAL METHANE EMISSION RATES
FROM ANIMAL WASTES
m> methane per kilogram volatile solids

Beef Cattle Dairy Swine Poultry
Cattle
Safley,
et. al.* 0.18 0.26 0.26 - 0.36 0.28
Hashimoto,
et. al. 0.17 - 0.33
Chandler,
et. al. 0.27 0.41 0.29
Jewell,
et. al. 0.33 0.22 0.38 0.49

® Safley, M.L. and P.W. Westerman, "Biogas Production from

Anaerobic Lagoons," Biological Wastes, Vol. 23, 1988,
pp. 181-193.

b Hashimoto, A.G., V.H. Varel and Y.R. Chen, "Ultimate
Methane Yield from Beef Cattle Manure; Effect of
Temperature, Ration Constituents, Antibiotics and Manure

Age," Agricultural Wastes, Vol. 3, 1981, pp. 241-256.

© Chandler, et. al., Second Symp. Biotech. Energy Prod.

Conversion, 1979.

q Jewell, et. al. Fuel Gas Production from Biomass, D.L.
Wise (ed.), CRC Press, Boca Raton, Vol. 1, p. 215.

Page C-12



Measurements of CH, emissions from waste ponds have been
undertaken as part of efforts to capture this CH,. Safley and
Westerman (1988) report the following estimates of biogas
production from waste ponds:

° Poultry digester effluent: 1.38 m/kgVS that is 65-85%
CH, ;

° Dairy wastes: 1.50 m/kgVS that is 80% CH,; and
° Swine wastes: 0.75-0.80 m/kgVS that is 85-95% CH,-

Thege data indicate that CH, emissions may be on the order of

1m per kilogram of VS added to the ponds during certain periods
of the year. These conversion rates are much larger than the
conversion rates listed in Exhibit C-2, and it is unlikely that
these rates can be sustained throughout the year.

The extent of CH, emissions from waste piles has yet to be
quantified or measured. Acid formation in the decomposition
process may inhibit CH, creation in waste piles.

Based on available data, Casada and Safley (1990) estimated
CH, emissions from animal wastes. Their estimates include the
following:

. Animal populations. Data were collected by country on
the number, size, and feed types for the following
populations of animals: beef and dairy cattle;
buffalo; swine; poultry; sheep; goats; and
horses/mules/donkeys.

. Waste quantities. The amount of waste produced per
animal was estimated for each country or region, taking
into account differences in animal size and feed. The
amount of VS produced was estimated, and the maximum
amount of CH, that can be produced from each waste
quantity for each animal type was estimated. This
maximum is used to estimate the CH, emissions

potential.

. Waste management. A set of waste management practices
was defined. The portion of waste handled using each
system was estimated. The systems used were:

-- —_- pasture/range;
-- daily spread;

34 m/kgVS = 1 cubic meter of biogas generated per

kilogram of volatile solids added to the pond.



TABLE OF CONTENTS

C.4 References ..... 5. see.

APPENDIX D AGRICULTURAL SOURCES .
D.1 Flooded Rice Cultivation
D.2 Managed Livestock... .
D.3 Biomass Burning.....
D.4 References .......

APPENDIX E LIST OF WORKSHOP ATTENDEES .

iv

C-17

D-1
D-1
D-10
D-18
D-20



. Distribution system normal operations. These emissions
are primarily associated with small leaks that develop
in distribution piping, e.g., due to corrosion. Very
little data are available for estimating these
emissions, and emissions could be much larger or
smaller.

Not included in these estimates are potential emissions
associated with gas appliances and industrial equipment.

Based on the data developed by PG&E and the PSI studies, it
appears that CH, emissions from natural gas system leakage may be
smaller than has been previously believed, at least for the y.s.
and potentially for other countries with similar operations.

It must be emphasized, however, that i
uncertainties remain. While these initial studies indicate that
leakage from natural gas systems may be on the order of 1.0
percent of annual gas throughput, field data are not yet
available to confirm these estimates. Consequently, CH,
emissions from natural gas systems could be larger or smaller
than indicated by these studies.

Emissions Reductions

Many opportunities exist for reducing CH4 emissions from the
production, transmission, distribution and use of natural gas.
Application of these methods could reduce CH, emissions from
natural gas systems to 0.1 to 0.5 percent of worldwide
throughput.

. Reducing emissions from the natural gas transmission
system in the Soviet Union. The Soviet Union has the
largest reserves of natural gas in the world and
exports large quantities of natural gas to Western
Europe. It has been suggested that the natural gas
transmission system in the Soviet Union may leak
significant quantities of CH,. Reducing these
emissions could lower not only current emissions but
future emissions as the Soviet Union expands natural
gas production.

3 see for example, A.D. Little, "Methane Emissions from the

Oil and Gas Production Industries," Final report to Ruhrgas A.G.,
July 1989; Wernstedt, G. and G. Fermback, "Releases of Methane
from Natural Gas Activity in Sweden," prepared for Swedegas by
Thorell + VBB Energikonsulter AB, August 29, 1989; and The
Alphatania Group, "Methane Leakage from Natural Gas Operation,"
July and August 1989.



5. FINDINGS FOR OIL AND GAS SYSTEMS

1. Emissions Estimates

1.1

Previously published estimates of global methane
emissions from oil and gas systems have relied on
estimates of 2-4% leakage (by assuming all "unaccounted
for" gas is emitted to the atmosphere), resulting in
global emissions estimates on the order of 25-45
million metric tons per year.

Recent preliminary studies based on extrapolating data
from selected gas systems indicate that methane
emissions from the U.S., Canada, Japan, and Western
Europe may be much smaller than previous estimates, and
are likely under 1% of throughput (with the possible
exception of some countries which rely heavily on old
gas systems). These studies are based on accounting
and engineering analyses that vary in detail and
methodology.

While projections of primary energy provided by natural
gas show significant increases, methane emissions from
gas systems are not expected to increase
correspondingly since newer, tighter piping and
production equipment will be used and older system
components will continue to be replaced.

2. Steps to Improve Emission Estimates

2.1 Many uncertainties remain regarding total methane
emissions estimates from natural gas systems and
regarding emissions in particular regions of the world.
The key uncertainties which need to be addressed are:

. emissions from abandoned and old wells;

° post-meter emissions;

. emissions from systems in Eastern Europe, USSR,
and developing countries; and

%3 4 million metric tons = 10° kilograms = 10" grams = 1

teragram

=1g
34



Richard L. Kerch
Consolidation Coal Co.
Consol Plasa

1800 Washington Rd.
Pittsburgh, PA 15241

Tel: 412-831-4527
Fax: 412-831-4916 or 4571
Telex: 247634

c. B. Kolb

Aerodyne Research, Inc.
45 Manning Road
Billerica, MA 01821

Tel: 508-663-9500
Pax: 508-663-4918

Adam Kotas

Btate Gelogical Institute -
Poland

ul. Bialego 1/11

41-200 Sosnowiec, Poland

Tel: 66 30 40
Telex: IGOG PL 0312295

Dina Kruger

U.S. EPA, AMR 445
401 & Street, sw
Washington, DC 20460

Tel: 202-245-3958
Pax: 202-382-6344

Vello Kuuskraa
IcP Resources
9300 Lee Highway
Yairfax, VA 22031

Tel: 703-934-3000
Fax: 703-691-3349

Daniel A. Lashof

Natural Resources Defense
Council

1350 New York Ave., NW
Washington, DC 20005

Tel: 202-783-7800
Pax: 202-783-5917
Telex: 4900010562 (NRD UI)

Abbie W. Layne

US Dept. of Energy
Morgantown Energy Technology
Center

3610 Collins Ferry Road
Morgantown, WV 26507

Tel: 304-291-4603
Fax: 304-291-4469

Robert Lott

Gas Research Institute
8600 W. Bryn Mawr
Chicago, IL 60631

Tel: 312-399-8302
Fax: 312-399-8170
Telex: 253812

Linda Lottman-Craigg
Seangas/Geomet, Inc.

Rt. 1, Box 98¢

Paeonian Springs, VA 22129

Tel: 703-777-0081
Fax: 703-771-4972

Lessek Lunarsewski

N.8.W. 2291
Australia

Tel: 61-49-296646
Pax: 61-49-296606

Page E-16



EXHIBIT D-3

PATHWAYS FOR CH, PRODUCTION

Complies substrates
‘A0P Fa NAO
arpa” ‘Seat tomate “wane

=e --
co, ed Electron occeptors:
subsionces
pyruvate
u —L ?
meianot 2 proponal, butonot ‘ethonol acetole Hy butyrate Glycerol formate
sactote succinaie 2, S dutun due,
glycerol loctote
co, C02
CH,
cH, CO, H, + acetone acelole = CH, ocelole propionate He co,
C02
CO, Con
CH.
cH, CO, ocetare,COz Ct
CH, CO,

Source: Neue and Sharpenseel (1984)

Page 0-5



. assessing the applicability of various utilization
options at mines with different gas quality, production
yates, and regional needs.

In addition, large quantities of CH, are currently removed
from mines in concentrations of 1 percent or less and vented to
the atmosphere. While wider application of degasification
systems and emphasis on maximizing CH, recovery may cause the
amount of CH, vented in this manner to decrease somewhat, coal
mines will always require ventilation, and CH, will continue to
be produced in this manner. Thus a final area for future
research could be to explore uses for the low quality CH, in
ventilation air streams. This CH, may be useable as combustion
air in nearby powerplants. Further, additional research could be
directed at exploring ways to separate low quality CH, from the
air stream to produce a more concentrated product.

B.3 Combustion: Stationary and Mobile sources
Emissions

Combustion sources include both stationary (e.g., fossil
fuel fired power plants and industrial boilers) and mobile
sources (e.g., automobiles, trucks, airplanes, and ships). CH,
emissions from these combustion sources are, in general,
associated with incomplete combustion of fossil fuels. Although
CH, may not be a component of the fuel, it can be created during
the combustion process.

While there is considerable uncertainty in the estimates of
CH, emissions from these combustion sources, existing data
indicate that CH, emissions associated with the combustion of
fossil fuels are much smaller than CH, emitted during fuel
production. A range of recent measurements are presented in
Exhibit B-3. It is useful to note that if the world's 300
exajoules of current energy demand resulted in CH, emissions at a
rate of 10 g/Gs’, that fossil fuel combustion would produce about
3 Tg of CH, annually. A more detailed estimate would involve
using the emissions factors listed in Exhibit B-3 and estimates
of the amount of energy consumed by each combustion source
globally. While many uncertainties remain, it appears likely
that combustion sources will be a large source of CH, emissions.

* 1 GJ =a gigajoule = 10° joules.

Page B-14



Fuel switching to natural gas leads to environmental
benefits in the form of lower emissions of S02, NOx,
and particulates.

Where possible, substituting the direct use of natural
gas for electricity generated by fossil fuels leads to
considerable CO2 emission reduction. The scope for
this should be evaluated further.

Before a fuel switching strategy can be adopted, it
must be clear that methane emissions from natural gas
operations will not counteract the CO2 reductions.

This would require estimates of both methane and COo2
emissions and a C02 equivalence for methane to be used
to calculate the actual reduction that is achieved from
fuel switching.

In determining the CO2 credit for fuel switching it
will be necessary for policy makers to assign the
appropriate global warming potential (GWP) to methane
in accordance with specific policy goals. It will also
be necessary to estimate methane emissions from the
fuel switching and the methane emissions from oil and
coal.

If methane emissions from natural gas systems are as
low as preliminary data imply, policies which will
encourage use of natural gas in appropriate cases need
to be developed. These policies need to address gas
use in all sectors -- electricity generation,
transportation, industry, and commercial and
residential appliances.

Information assessing world-wide resources of natural
gas should be improved ~-- large areas of the world
remain unexplored. If methane emissions from natural
gas systems are as low as preliminary data imply,
further exploration and identification of reserves
should be promoted. Natural gas potential from coal
seams should be assessed globally. Policies which will
encourage continued investment in natural gas
infrastructure may need to be developed.

37