Qualco Energy biogas project is paying off

Located in Washington’s Tualco Valley, the Qualco Energy Corp. anaerobic digester project in Snohomish County has come a long way since the project was conceived in 2003. At the Pacific West Biomass Conference & Trade Show held in Seattle, attendees got the opportunity to see the fruits of its labor up close and personal.

Qualco Energy, a nonprofit organization formed jointly by representatives from the Sno/Sky Agricultural Alliance, Northwest Chinook Recovery and the Tulalip Tribes, officially began operation of the digester in 2008. The digester was first proposed to help consume waste from local dairy operations and to prevent runoff into local salmon streams on land that formerly housed a correctional facility, which closed in 2002 after 60 years of operation.

According to Daryl Williams, environmental liaison for the Tulalip Tribes, Qualco Energy uses a modified mixed plug flow mesophyllic digester capable of producing 600 cubic feet-per-minute of biogas that powers its 450-kilowatt generator. Manure is collected from 1,400 cattle at Werkhoven Dairy’s three dairy farms and is piped to Qualco’s 2 million gallon digester tank. Although manure is its primary feedstock, Williams said the digester can also take in expired beer and soda and waste trap grease.

“We’re producing a lot more gas than I thought we would before we built the facility,” Williams said. “Now that we’re using more [feedstock] in the digester I think it’s paying for itself.”

Qualco Energy sells its electricity to utility provider Puget Sound Energy Corp. and is negotiating a power-purchase agreement with the Snohomish County Public Utility District. Excess biogas that doesn’t go to the utilities is burnt off. Williams said about two-thirds of the company’s biogas gets released. The company is also selling carbon credits, Williams continued.

The solids leftover from the anaerobic digestion process, according to Williams, are collected and stored in a building where they are used as compost material. Although Qualco Energy currently gives its digestate material away for free, Williams said they will charge a fee once a market is found for it.

“We’ll hopefully sell the solids for about $10 per yard,” Williams said.

Waste liquid from the digester gets piped to a nearby lagoon where it’s held until the summer when it will be utilized for irrigation purposes.

Qualco Energy was able to leverage state and federal funding in order to launch the project. The company received a $500,000 grant from the U.S. DOE to conduct an environmental assessment and economic feasibility study in 2005. Additionally, the company received $500,000 from the USDA to help pay for the digester.

Williams said the economic and environmental impact of the anaerobic digester has been a tremendous boon for the county, adding that Qualco Energy intends to expand operations to include additional generators and installation of solar panels.

“This is an exciting benefit for the county,” Williams said. “We’re intercepting waste and diverting it for use as renewable energy. It doesn’t get much better than that.”