|The pipeline from landfill to GM plant in Shreveport. One of seven GM LFG projects.|
General Motors is the largest direct, corporate user of landfill gas (LFG) as a replacement for natural gas in the United States. General Motors has reduced its natural gas consumption by 21% since 2000 and is expected to achieve its goal of a 25% energy reduction by the end of 2006.
At GM facilities, the LFG is piped to the plant and combusted in boilers, providing a cost-effective, renewable energy source. The sum of landfill gas capacity at the seven GM operations using the fuel is equivalent to the energy needed to heat over 25,000 households, which represents about 1.6 trillion BTUs per year.
Landfill gas is a natural product of the biological decomposition of organic waste. The resulting gas has a variety of chemical components, but at most sites the two principal components are methane (CH4) and CO2, with much smaller amounts of hydrogen sulfides (H2S), inerts and volatile organic compounds (VOCs).
A problem with LFG projects is the presence of trace components. Typical LFG contains heavy hydrocarbons (both aliphatic and aromatics such as benzene) as well as numerous chlorinated hydrocarbons. These trace compounds are in some cases toxic or hazardous and also cause rapid failure or engine and turbine components. There are now federal statutes which cover landfill emissions.
GM’s LFG use is being featured this spring on two television programs airing on public and cable television stations throughout the United States and on Voice of America programming internationally. Both programs look at how the rotting garbage in landfills generates a gas that is used as an energy source at seven GM facilities.
The “Learning About” educational series is hosted by actor Michael Douglas and will air during March. Later in the spring, GM will be featured on “The Global Learning Series” education program.
GM’s Orion Township, Michigan, assembly plant is highlighted in the “Learning About” and “The Global Learning Series” television programs.
Other GM facilities using landfill gas are: assembly plants located in Oklahoma City, Okla. ; Fort Wayne, Ind. ; Shreveport, La. ; and a powertrain plant located in Toledo, Ohio. Two additional warehouse sites in Grand Blanc and Flint, Mich., utilize landfill gas by purchasing 13 million kilowatt-hours of electricity annually, which is generated from a landfill gas-to-electricity program.
The US Environmental Protection Agency (EPA) awarded GM one of its Landfill Methane Outreach Program (LMOP) awards for the Ft. Wayne Truck Assembly Plant LFG project.
An 8-mile pipeline delivers LFG from the Macbeth Road Landfill to the plant, providing about 450,000 million BTU per year. This represents about 16% of the plant’s energy needs, saving GM $500,000 annually. The LFG use delivers annual greenhouse gas reductions equivalent to planting 6,000 acres of forest, removing the emissions of 4,200 vehicles, or preventing the use of 51,200 barrels of oil.