Energy from Cow Manure: It’s not Just for Fertilizer Anymore

To the list of odd sources of power generation add another novel method:   cow manure.

CVPS Cow Power, the first manure-to-energy program in the country, was named Utility Green Power Program of the Year at "Renewable Energy Markets 2009," an international energy conference. The U.S. Environmental Protection Agency (EPA), the U.S. Department of Energy (DOE), and the Center for Resource Solutions (CRS) sponsor the Green Power Leadership Awards, which recognize the actions of individuals, companies and organizations that significantly advance the development of renewable electricity sources through green power markets.

The Cow Power program, part of Central Vermont Public Service (CVPS), solves several environmental problems at once by providing customers with clean, renewable energy, preventing methane from entering the atmosphere, and helping farms sustain themselves in an eco-friendly way.

Cow Power creates energy by holding manure and other agricultural waste in a sealed concrete tank at the same temperature as a cow’s stomach: 101 degrees. Bacteria digest the volatile components, creating methane and killing pathogens and weed seeds. The methane, a greenhouse gas which is roughly 20 times more harmful than carbon dioxide in trapping heat in the atmosphere, fuels an engine/generator.

The anaerobic bacteria digesters also solve the problem of manure management. Manure is processed through a mechanical separator; the solids are dried and can replace sawdust or sand as bedding for the animals because any pathogens are killed during digestion – as well as all manure odors. That use alone saves participating farms $80,000 to $150,000 annually. Cow Power also provides participating farmer-generators with a steady income stream that offsets fluctuations in milk prices. Farmers can use excess heat from the engine-generator to heat water and provide space heating, at a savings of $10,000 to $15,000 annually.

CVPS customers can choose to receive all, half or a quarter of their electrical energy through Cow Power, and pay a premium of 4 cents per kilowatt hour. The money goes to participating farm-producers, to purchase renewable energy credits when enough farm energy is not available, or to the CVPS Renewable Development Fund, which provides grants to develop on-farm power generation. Farm-producers are paid 95% of the market price for all of the energy sold to CVPS.

In announcing the award, the DOE said, "CVPS Cow Power, developed by Central Vermont Public Service, is one of the nation's first farm-to-consumer renewable energy programs that uses methane-based power generation from cow manure to provide clean, renewable energy while solving numerous environmental problems. Since the program's inception in 2004, a total of over 42 million kWh have been sold through customers participating in the program."

CVPS won the Utility Green Power Program of the Year award for designing and implementing the voluntary renewable energy program, which competed against hundreds of utilities, including municipal, electric cooperatives and investor-owned utilities that offer voluntary renewable energy programs to their customers.

Lt. Governor Brian Dubie, who was an early supporter of CVPS Cow Power and nominated CVPS for the award, said it was a model for others to emulate. "The thinking that created Cow Power, turning a waste stream into an asset, is just the kind of thinking we need as we face growing energy and environmental challenges," Dubie said. "We hope to inspire other states and regions to follow our success with the Cow Power program."

Image coutesy of Everything French Gardening