Waste Management is doubling capacity at its landfill gas power plant south of Arlington, generating more energy for homes and businesses 260 miles away in Seattle.
The Columbia Ridge Landfill and Recycling Center handles approximately 2 million tons of garbage per year, approximately one-third of which is shipped in by rail from Seattle Public Utilities. Once transferred into the dump, organic waste starts to decompose, releasing methane gas as a natural byproduct.
Gas is collected via a system of 85 wells at Columbia Ridge, and fed into a power plant on site where it is used as fuel to generate electricity. The plant recently added four new engines, which are expected to come online in August.
With the expansion, capacity will increase from 6.4 megawatts to 12.8 megawatts — or enough to power roughly 12,500 homes. Seattle City Light, the country’s 10th-largest public electric utility serving more than 400,000 customers, has agreed to purchase all electricity produced at Columbia Ridge.
That means every time Seattle residents take out the trash, they’re helping keep the lights on for thousands of homes and businesses throughout the city.
“We’re pleased this is taking advantage of what would otherwise be a wasted product,” said Scott Thomsen, City Light spokesman. “You’re literally taking people’s trash, and turning it into a valuable resource.”
In addition, Washington state law requires large utilities to obtain 15 percent of their electricity from renewable sources developed after 1997. Investing in landfill gas is one way utilities like City Light can work to meet that goal, Thomsen said.
“It’s one of the strictest (energy) portfolio standards in the country, if not the strictest,” he said. “This project helps us get a small piece of that requirement taken care of.”
Columbia Ridge opened in 1990 under a licensing agreement with Gilliam County, though the landfill gas power plant did not begin operating until 2009. The 12,000-acre dump is also a platform for other green technologies, including wind turbines and a demonstration project converting household waste into fuel through plasma gasification.
Jackie Lang, Waste Management spokeswoman, said the company is always looking for ways to leverage infrastructure, especially in places like Gilliam County where they have formed a strong partnership over two decades.
The project also presented an opportunity to help the city of Seattle achieve its renewable energy objectives, she said.
“We are committed to being the best partner we can be, and continuing to invest in our local infrastructure,” Lang said.
Gilliam County Judge Steve Shaffer said the Columbia Ridge power plant shows how they can take products people throw away every day and turn it into something that benefits everyone in the region.
By bringing in a variety of wind, solar and landfill gas technology, Shaffer said he is proud of the county’s commitment to providing renewable energy.
“I feel we’re a very green-friendly county,” Shaffer said. “I think that’s where we have to look into the future.”
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