How is Landfill Methane Used?

Landfill methane gas is produced by waste as it decomposes. This gas has been identified as a greenhouse gas and is considered to be the second largest contributor to global warming. Gasses produced by landfills are between 40 to 60 percent methane and the remainder is mostly carbon dioxide. The methane that is produced in landfills can be reduced by proper landfill procedures but the gas can also be recovered for the production of electricity.

Gas to energy conversion is achieved by drilling wells in locations throughout a landfill. Gasses are vacuumed out and sent through a compressor. For there the gasses are sent to engine generators which burn the gas to create electricity. Methane landfill gas or biogas can also be used to produce heat. The burning of the methane gas produces only carbon dioxide and no other harmful gasses. Oil burning plants produce much more in the way of emissions and dirt than methane burning plants.

Methane gasses produced by landfills are considered to be a consistent source of energy. Conversion plants running on methane gasses are online close to 95 percent of the time and are reliable for providing a steady source of power. Power produced by methane gas conversion can be used by industries or homes.

A gas to energy plant in Ferris, Texas is generating 6 megawatts of energy. This is enough energy to power close to 6,000 homes. A plant at Cherokee Run landfill is producing approximately 4.8 megawatts, enough electricity to power almost 2,800 homes. Wells at the Cherokee Run plant should be able to pull in gas for ten to twenty years before they will need to be replaced or relocated. It is estimated that this one plant will be able to continue electrical production for between 30 to 40 years.

Other uses for captured methane gasses included heating greenhouses, fueling garbage trucks and firing brick kilns. Fuel is also provided for automobile and chemical manufacturing. Large and small scale reclamation projects are under way and funding for these projects comes from both public and private sectors.

The amount of methane emissions from landfills is estimated to be between 30 to 70 million tons per year globally. This is a large amount of useable energy that can be captured. Landfills continue to produce methane gasses even after they are closed due to the waste that still decays underground. These gas to energy plants not only help to reduce the greenhouse gasses emitted by landfills but also are able to provide a renewable energy source.

References:

http://www.examiner.org/index.php?option=com_content&view=article&id=7027%3Aelectricity-produced-at-cherokee-run-landfill&Itemid=55

http://www.msnbc.msn.com/id/19459535/

http://www.ghgonline.org/methanelandfill.htm

http://www.epa.gov/lmop/projects-candidates/index.html