REXVILLE — It takes slightly more than three gallons of liquid cow manure to create one kilowatt-hour of electricity.
A lot of poop. A small amount of electricity. A big environmental boost to a dairy farmer.
A fledgling anaerobic manure digester is now running at roughly 80 percent capacity near Rexville in southwestern Skagit County. The plant produced its first power on Aug. 30 and will host Gov. Chris Gregoire at a ceremony next Monday.
The digester accepts the liquid manure in a big holding tank, where it gives off methane gas that is then burned to produce electricity.
It is the first or fourth of its kind in Washington — depending on how you catalog the device. Ferndale-based Andgar Corp. built all four.
Washington already has three conventional poop-to-methane-to-power digesters near Lynden, Monroe and Sunnyside. However, they essentially accept manure from one dairy farm each.
The Rexville operation — built and run by Farm Power — is different in a couple ways.
It is set up to accept manure from two or more dairy farms — enabling smaller operations to participate.
And it is designed to accept and extract methane from icky, slop-like wastes from seafood and chicken processing — as well as other food wastes. Farm Power had to get a bill passed in the Legislature this past spring to make combining the food and cattle wastes easier from a regulatory aspect.
Dairy farms produce huge amounts of manure that can ooze into groundwater and eventually into streams and rivers to cause pollution problems.
Farmers take many measures to deal with this problem, but digesters are a more cost-efficient way to tackle the matter, said Daryl Maas, one of two brothers behind the Rexville operation.
Kevin and Daryl Maas — who grew up around Skagit County dairy operations — saw Washington’s first digester built near Lynden in 2004 and became fascinated by its potential.
But they saw that very few farmers could afford to build similar digesters, Daryl Maas said.
The brothers created Farm Power in 2007, which raised $3.5 million — including $1 million in federal and state grants — to build the Rexville facility that is currently taking manure from two nearby dairy farms. The site has the capability to expand to accept manure from additional farms.
At full capacity, the Rexville site can handle 55,000 gallons of liquid manure a day. That translates to 750 kilowatt-hours — enough to power about 500 homes.
That’s one-tenth of 1 percent of the roughly 500,000 homes served by Puget Sound Energy.
The Rexville facility adds to what PSE can offer in “Green Power,” a program in which utility customers can request to have their electricity partly or totally supplied by renewable sources such as wind, solar and biomass facilities.
Roughly 24,000 of PSE’s 1.1 million overall customers have signed up for Green Power sources, said utility spokesman Andy Wappler.
“Now farmers have a brand-new product to sell — renewable energy,” Wappler said. Maas said the brothers have three more digesters on the drawing board — two in Whatcom County and one near Enumclaw. They hope to build an average of one per year.
Meanwhile, Maas said the manure can be returned to the farmers in better shape after the methane is extracted.
The returned manure has its nutrients broken down, which makes it a better fertilizer. Without going through the digester, the same manure would take longer to break down into essential nutrients for fertilizer.
Also, the process produces a mulch that can be used for livestock bedding.
Information from: Seattle Post-Intelligencer, www.seattle-pi.com/
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