The Prince William County Landfill produces enough methane to power 5,000 to 6,000 houses, but it hasn’t been using all of that methane to produce electricity. The two engines, which currently run on methane to generate the power, have been operating at capacity for some time and are unable to handle all of the methane the landfill produces.
When the two engines were installed in 1996, they were sufficient to handle most of the gas generated at the time. “Over time, as the landfill grows, more trash is in the landfill and we add more wells. So, we’ve been burning it off in a flare for years,” Smith said. This way, the gas is burned off before it gets into the atmosphere.
In November, three additional engines will be up and running to allow the landfill to produce roughly 65 percent more electricity, which will hook into to the electric power grid through the Northern Virginia Electric Cooperative (NOVEC).
The County has partnered with the renewable energy company Fortistar, which will finance, construct and run the power plant operation. “We get some of the revenues that come back and we’re helping to finance the infrastructure, but the full cost of the power plant is handled by our private partner,” Smith said.
Smith said home owners near the landfill could claim to be using the power of trash. “If you live around the landfill, the electrons in your house are very likely coming from this power plant. Whoever’s closest to the landfill will get the power first.”
Smith said capturing methane at landfills is a common practice, but many of the smaller operations simply burn the methane to get rid of it.
“Not all landfills make power onsite. Some of them will just flare it depending upon the quantities. There are bigger landfill gas power plants out there, but this expansion puts us in another level. This would be considered a large gas recovery facility,” he said.
The cost of the Landfill Gas Power Plant expansion, according to Fortistar, is $11 million. These costs are paid by Fortistar. The County will receive additional funds for gas rights and share of electric revenues, about $130,000 per year.