The Methane Goes Round and Round
Every day, the 550 half-ton Holstein cows on Dennis Haubenschild’s dairy farm near Princeton, Minnesota each eat 90 pounds of food, produce eight gallons of milk and create 220 pounds of waste and manure.
On another farm, cows making a quarter of their weight in waste pose a daily hazard. Manure from dairy farms festers in large lagoons, threatening ground and surface waters. It also creates global warming gases like methane, and the stench keeps neighbors indoors.
But at Haubenschild"s, a family farm 10 times bigger than the average Minnesota dairy operation, each cow generates 5.5 kilowatt hours of electricity daily. That lets the neighbors smell the daisies on the windiest days and has eliminated the equivalent of 680 tons of carbon dioxide in 10 months.
Haubenschild’s methane-fired electricity generator, engineered with assistance from the Environmental Protection Agency’s AgStar Project, is a dream come true. "I’ve been interested in methane digestion since the 1970s," Haubenschild says. "I had no doubt that it would work; it just took quite a few years to tie everything together."
When federal environmental regulators" concern about the damaging greenhouse effects of methane—it’s 21 times as potent as CO2—and Minnesota agriculture officials" concern for declining farm incomes coincided in the late 1990s, Haubenschild was ready to take advantage of government programs that allowed him to build the $350,000 generating plant, which began operation in October 1999.
Haubenschild’s system, which captures methane created by anaerobic bacteria in a covered and heated cement manure pit, generated $62,000 of electricity and $4,000 of waste heat (used to replace propane) in its first year. He sells the electricity from his methane-fired generator to his utility for 7.25 cents per kilowatt hour. Although there are only 31 electricity-generating methane harvesters on U.S. farms, Haubenschild’s numbers shouldn’t have surprised anyone.
Dick Waybright, of Mason Dixon Farms near Gettysburg, Pennsylvania has operated manure digesters for 21 years. "They’re an important part of our profit picture. I get 30 percent annual return on our investment," says Waybright, who milks 2,150 cows with his sons.
"This project is an opportunity to use renewable energy and promote sustainable agriculture," says Henry Fisher of the Minnesota-based East Central Energy cooperative, which buys Haubenschild’s electricity. "We roll the energy into our green power program, which charges a premium over the retail rate to cover distribution costs."