Farm Power's digester will create electricity from cow manure

Aiming to harness the collective poop power of northwest Washington’s small dairy farms, Farm Power Northwest broke ground on its first anaerobic manure digester project in October.

Mount Vernon-based Farm Power partners with area farms—most of which are too small to operate individual digesters and market the resulting products—to create regional digesters, raise funds, build and operate the projects at no cost to farmers, Farm Power co-founder Daryl Maas says.

Farm Power’s project is intended to reduce odor and runoff while creating electricity by plugging a digester into the dairy farm’s nutrient loop. In the digester, manure and food waste are piped or trucked into a heated holding tank where they are digested by bacteria, releasing methane. Capturing and burning methane creates electricity, which can be sold back to the grid.

In April 2008, Farm Power announced an agreement with Puget Sound Energy (NYSE: PSD), to sell it the electricity and the associated renewable energy credits which the utility will use to help it meet Washington’s Renewable Portfolio Standard. Other byproducts from the process—nutrient-rich liquid manure and a clean fiber product that can be used for livestock bedding—are returned to the farmers.

The $3.5 million Mount Vernon digester, which will initially generate about 750 kilowatts, was funded by a $500,000 USDA grant, a $500,000 state grant and $2.14 million United States Department of Agriculture-backed loan from Ilwaco, Wash.-based ShoreBank Pacific. Through state legislation passed in March 2008, electricity-producing digesters are eligible for state property tax exemptions.

The Mount Vernon digester is expected to be up and running by mid-2009. Maas says he's heard a lot of interest in regional digester facilities in his talks with local farmers. So much so that the company has expanded its plans from three to five anticipated facilities to at least six more digesters in the Puget Sound region.

Each digester can process about 50,000 gallons of manure per day, or about 1,500 cows worth. With an estimated bovine population of about 100,000 in western Washington, Maas estimated potential for up to 20 digesters in the region.