Cow Power

Vermont had 2,500 dairy farms in 1993; now it has 1,400. The low price of milk is one culprit: it’s down from $17 per hundredweight (12.5 gallons) at its peak to $12 today. To stay competitive, dairies have to be innovative. One way they do that is by going organic, since organic milk fetches $30 per hundredweight. Another way is by emulating Blue Spruce Farm in Bridport, Vermont and tapping into cow power.

Marie Audet of Blue Spruce Farm, which is turning cow manure into energy. The methane from the farm’s 1,000 cows runs grid-connected generators. © CVPS

The farm, long owned by the Audet family, is sizable for Vermont, with 1,000 Holstein milking cows. Not a confinement system (the cows can move around their barn), Blue Spruce isn’t organic, either. But it’s green in another way. The manure from all those pooping cows, collected by “alley scrapers” that run along the floor like a giant squeegee, is processed into renewable electricity.

There are other benefits as well. David Dunn, a senior energy consultant with cow power sponsor Central Vermont Public Service Company, sticks his hand into a giant pile of powdery waste, unfazed by its former life as cow manure. The odorless byproduct makes excellent fertilizer, potting soil (“Moo Doo”) and cow bedding. “This farm doesn’t have to spend $1,200 a week on sawdust for bedding anymore,” he says.

According to Marie Audet, the family spokesperson, 400 homes could be powered by the electricity produced on the farm. The waste goes into an anaerobic (oxygen-free) digester and sits there for three weeks, during which time it produces methane (a fuel doubling as an extremely potent global warming gas) that is captured and used to power two large Caterpillar electricity generators, totaling 275 kilowatts. The Audets have invested $1.3 million in the operation, but with $120,000 a year in electricity sales they expect to recoup their costs in seven years.

Green Mountain College in nearby Poultney has agreed to buy 1.2 million kilowatt-hours of the Audets’ cow power electricity annually, tacking a $48,000 surcharge on its bill. “It’s time to walk the talk,” says Green Mountain President John Brennan on a recent tour of the cow barns and digester. “This helps the market for renewable energy, and it avoids the emission of global warming gasses.”

Other Vermont farms are also planning to invest in cow power operations, and the idea has gone national. The 2002 Farm Bill provides federal funds through the Renewable Energy Systems and Energy-Efficiency Improvements Program. Lodi, California’s Castelanelli Brothers Dairy (with 2,100 cows) tapped into it for $160,000 to help pay for an anaerobic digester that will produce up to 180 kilowatts. Another operation, also federally assisted, is underway at the Dairyland Power Cooperative in Elk Mound, Wisconsin. Cow power is on a roll.