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Landfill gas provides electricity
Methane-to-electricity facility begins operation

 The new renewable energy facility is located at the regional landfill in Stafford County.
ROBERT A. MARTIN/THE FREE LANCE-STAR
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Date published: 9/18/2008

BY HUGH MUIR

Officials cut a wide red ribbon at the Stafford-Fredericksburg landfill yesterday to start a renewable energy plant that will burn methane to generate electricity for the local grid, while producing income for the landfill.

"We have found truth in the old adage that one man's trash is another's treasure," Stafford Supervisor Paul Milde said in his remarks at the ceremony, attended by about 30 residents and officials.

Milde is also the chairman of the Rappahannock Regional Solid Waste Management Board, which owns the county-city facility.

The 2.4 megawatts per hour generated by the new installation will meet the annual power needs of 1,300 homes in the area. The board will receive $180,000 a year from a 20-year contract with Ameresco, a company that specializes in clean energy.

Methane, also called "greenhouse gas," is a renewable product that is constantly produced by the decaying matter deep within the landfill's hills of waste. Until now, the methane has been wasted because it was burned, or "flared off," to keep the heavy gas from building up on the ground.

The $3 million generating plant sits amid a cluster of landfill mounds, each of which is penetrated by pipes to siphon off the gas. The pipes hook up with larger pipes and finally, about 800 cubic feet per minute is fed into the generating complex.

There the methane is "cleaned up" through the extraction of impure elements that are carried with the gas. The fuel is then fed into one of two generating units, each a building about the size of a typical shipping container. The gas runs a large GE internal combustion engine, which in turn spins the turbines.

The electricity then is fed to power lines outside and sent along to a grid shared by Dominion Gas.

There are two such generating buildings. Each has a large cooling apparatus and a muffler sitting atop it to cool the interiors and keep the noise level down. If all goes well, officials say, a third generating building could go up, perhaps within a year.

The $180,000 received by the board will help maintain and expand the landfill operations. The landfill is self-supporting, with no funding from taxpayers.

There is a similar methane-burning operation in Fauquier County. A generating plant in Hopewell uses methane pumped to it through a 23-mile pipeline, the longest of its type in the country. A smaller landfill in Hanover uses the burning off of its methane to dry waste paint it receives before safely disposing of it.

Hugh Muir: 540/735-1975
Email: hmuir@freelancestar.com