NOVEMBER 2008

Cow manure powers Ohio Electric Cooperative lines

A herd of 3,900 dairy cows in northern Ohio is producing renewable energy in the state’s first-ever project to capture methane from manure for generation of electricity.

Bridgewater Dairy in Williams County fired up two generators at its new anaerobic biodigester facility and began flowing green power to Buckeye Power, Inc., and Ohio’s rural electric cooperatives.

Cow manure from the dairy is used to “feed” bacteria that thrive in an airless environment. The organic waste decomposes. Gaseous byproducts, including methane, are produced. Methane, a greenhouse gas 23 times more potent than CO2, is captured and used to fuel a pair of engine-and-generator sets capable of cranking out a maximum of 1.2 megawatts of electricity.

Dairy cow manure in Ohio is being used to cultivate bacteria that thrive in airless environments. The bacteria break down the waste into gaseous byproducts including methane, used to power engine sets.

Buckeye Power, Inc., has a contract with Bridgewater Dairy to purchase all of the electricity and will use it to provide green energy to the state’s 24 electric cooperatives. North Western Electric Cooperative in Bryan, Ohio, provided the grid interconnection via a 3-phase circuit on its 12.4-kilovolt system.

“Bridgewater, we believe, is the first animal waste biodigester in Ohio to come online and generate substantial amounts of power,” said Buckeye Power chief operating officer Pat O’Loughlin, adding that several such facilities exist in Wisconsin and other states with high numbers of dairy producers.

The facility’s output is determined by the amount of methane gas produced by the anaerobic digestion process. Generation has started at the 400 kilowatt level but should steadily increase. Normal operation will produce enough electricity to supply an estimated 400 homes.

For the owners of Bridgewater Dairy, the biodigester generation system provides revenue from the sale of electricity but also solves the problem of what to do with animal waste. After cow manure decomposes in the digester and loses its nutrient value to the “bugs,” as the bacteria are called, it can be used as a high-grade fertilizer to be spread or sprayed on pastures. The anaerobic process kills pathogens and substantially reduces the odor normally associated with agricultural application of manure-based fertilizer.

For Ohio electric cooperative members, green power from Bridgewater Dairy presents an opportunity to help reduce greenhouse gas emissions by using a renewable form of energy. Biodigester generation becomes the primary source of supply for the Envirowatts green power program offered by Buckeye Power through participating electric cooperatives.

A second biodigester generation system - this one using waste from a poultry farm - is expected to come online soon to generate more renewable energy for members of Ohio’s family of electric cooperatives.