Methane from landfills to light up Seattle

Seattle's latest renewable-energy source is methane — landfill gas created as garbage decomposes. And the energy it produces costs half as much as wind power.

Seattle ships its trash — about 400,000 tons a year — by rail to a Waste Management-owned landfill in Arlington, Ore. As part of a contract reached last year, Waste Management agreed to begin turning the landfill's methane into energy and sell it to Seattle.

City Council members, utility officials and Waste Management executives announced Thursday in a Sodo rail yard that the plant has begun making electricity, completing the circle of waste-to-energy that was envisioned when Seattle started sending its garbage to Oregon in 1991.

"It's part of the path that Seattle is on," said City Council President Richard Conlin, who shouted over trains and a helicopter during his brief remarks and made a crack about batting "clean up" as the last speaker in the garbage news conference.

Seattle has sent rail cars full of garbage to the 700-acre Columbia Ridge Landfill in Arlington for 19 years. The landfill gets about 2 million tons of trash a year from Oregon and Washington.

In the past, the landfill burned off the methane produced by decomposing garbage. Now the methane is captured and piped to a plant where it powers combustion engines that generate electricity.

The energy plant will provide Seattle 5.78 average megawatts — enough to power 5,625 homes.

Seattle City Light is already a green utility, compared to other urban systems. It relies mostly on hydropower. In order to meet the goals of Initiative 937, though, Seattle City Light has to increase its renewable-energy supply by 238 megawatts by 2020.

Initiative 937, approved by voters in 2006, requires large utilities to get 15 percent of their energy from renewable sources by 2020.

"While it is a small part of a bigger challenge that Seattle faces, it is a very important part," said City Light Superintendent Jorge Carrasco.

Emily Heffter: 206-464-8246 or eheffter@seattletimes.com