Methane from cow manure generates sustainable electricity
By BILL GLAUBER
Posted: June 25, 2007
Waterloo - At the Crave Brothers Dairy Farm, they grow corn and soybeans on 1,600 rolling acres of prime Wisconsin farmland, raise a herd of 750 dairy cows and produce prize-winning cheeses out of milk pumped straight from farm to factory.
But this year, the four Crave brothers added a new line to their family-run agribusiness.
They're turning manure into enough electricity to power 200 homes.
With the flick of a keystroke on a computer, Gov. Jim Doyle literally threw the switch Monday for the ceremonial start-up of an anaerobic digester at the sprawling Crave Brothers farm.
Why is this digester any different from the 23 others scattered around the state?
For one thing, it's fully automated. For another, the operation can be monitored from a computer desktop in Milwaukee, home to Clear Horizons and its holding company, PPC Partners, which bankrolled and built the $2 million digester.
Now, if they could just figure out a way to make a profit.
Richard R. Pieper Sr., chairman of the holding company, figures it costs 20 cents per kilowatt hour to produce energy at the Crave Brothers farm, but the firm receives only 5 cents per kilowatt hour from the local power company.
That's a pretty big loss leader.
"The wind people get 12 cents," Pieper said. "Solar gets 22 cents. We get a nickel. Give us those rates (wind and solar), and we can build more of these."
But Pieper is optimistic the venture can become profitable as well as do some good in helping the United States wean itself from foreign oil.
That's a point driven home by the governor.
"We want to produce 25 percent of our power from renewable resources by 2025," Doyle said.
Doyle said "it's not a pipe dream" to believe Clear Horizons' estimates that Wisconsin's agriculture industry has the potential to generate enough biogas to power 175,000 homes.
Even as a loss leader, though, the digester accomplishes quite a bit.
Take the manure, please.
There's around 1 million gallons of the stuff sitting in a massive holding tank and, amazingly, not much of a smell. The manure is heated at 105 degrees and breaks down over a month. Methane rises to the top to produce biogas, which is then used to generate electricity.
A couple of other products are also created. Liquid is used as fertilizer on the farm. Other solid material is used as bedding for the cows.
And, finally, a line of organic potting mixes is served up. It's called EnerGro.
Charles Crave, who oversees the farm's finances, said turning manure into power has been a dream of his for 25 years.
"You take a farmer's dreams and a visionary like Dick (Pieper) and you keep talking and talking, you finally get the job done," Crave said.
In a barn the length of a football field, the cows stand on slotted floors. Manure flows away through gravity.
No muss, no fuss.
"When you're handling many millions of gallons of manure, any way to handle that risk is helpful," Crave said. "What is in this for us is manure management, odor reduction. And a chance to move the operation forward using modern technology."
Amazing what you can do with 1 million gallons of manure and $2 million of investment.