1 For a landfill gas coefficient per thousand standard cubic foot,
multiply the methane factor by the share of the landfill gas that is methane.
2 These biofuels contain "biogenic" carbon. Under international
greenhouse gas accounting methods developed by the Intergovernmental Panel on Climate
Change, biogenic carbon is part of the natural carbon balance and it will not add to atmospheric
concentrations of carbon dioxide.3 Reporters may wish
to use an emission factor of zero for wood, wood waste, and other biomass fuels in which the
carbon is entirely biogenic. Municipal solid waste, however, normally contains inorganic
materials principally plastics that contain carbon that is not biogenic. The proportion of
plastics in municipal solid waste varies considerably depending on climate, season,
socio-economic factors, and waste management practices. As a result, EIA does not estimate a
non-biogenic carbon dioxide emission factor for municipal solid waste. The U.S. Environmental
Protection Agency estimates that, in 1997, municipal solid waste in the United States contained
15.93 percent plastics and the carbon dioxide emission factor for these materials was 5,771 lbs
per ton.4 Using this information, a proxy for a national
average non-biogenic emission factor of 919 lbs carbon dioxide per short ton of municipal solid
waste can be derived. This represents 91.9 lbs carbon dioxide per million Btu, assuming the
average energy content of municipal solid waste is 5,000 Btu/lb.
3 Intergovernmental Panel on Climate Change. Greenhouse
Gas Inventory Reference Manual: Revised 1996 IPCC Guidelines for National Greenhouse Gas
Inventories, Vol. 3, Pg. 6.28, (Paris France 1997).
4 U.S. Environmental Protection Agency, Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990-1998, EPA 236-R-00-001, Washington, DC,
April 2000.