COW-POWER TOWN: A prairie community considers generating biogas from dairy manure

BY E.M. MORRISON
Morris, Minn. — A west-central Minnesota community may become a new kind of cow town.
 

Morris officials want to build an anaerobic cattle-manure digester at a nearby dairy farm. The digester would produce methane, a renewable fuel that could be transported to town and sold to local industries. AURI’s Center for Producer Owned Energy and Minnesota soybean and corn growers associations provided funds to help Morris, population 5,000, take a closer look at municipal methane.
 

The concept “is not entirely new,” says Ed Larson, Morris city manager. Some cities, for example, pump methane from decomposing garbage in landfills, using it to generate electricity. “With a large dairy farm nearby, the opportunity is there to make methane,” Larson says. “The City Council was interested, so we said, let’s explore it and see if there’s a marketable product.”

The project calls for building an anaerobic manure digester and methane transportation system at West River Dairy, a farm about eight miles southwest of Morris. Run by the Fehr family, the farm is one of the largest milking operations in the state. Its 5,000 dairy cows produce eight million cubic feet of manure a year.
 

The same process that eons ago produced natural gas from ancient plants can be used today to make methane, a natural-gas component, from cattle manure. The manure flows into a digester — essentially a tank or covered basin — where bacteria break down the organic material, making methane as a byproduct. The methane is drawn off and used like natural gas for heating or to run engines that produce electricity or mechanical power. Like natural gas, methane can be transported to distant
users in pressurized tanks or pipelines.
 

The plan’s feasibility is being assessed by Sebesta-Blomberg, a Roseville engineering firm that specializes in energy utilities. The study led by senior engineer Cecil Massie, a renewable energy expert, will evaluate technical issues such as gas production and transportation, manure management,
construction and operating costs, financing, and biogas marketing.
 

Morris, home to state and federal agricultural research stations, as well as a University of Minnesota campus, is the site of several green-power demonstration projects, including wind energy and biomass
gasification. (See “Green Power on Campus,” July 2005 Ag Innovation News.)

The municipal-methane idea grew out of a 2003 report from the Energy Environment Research Center in Grand Forks, N.D., which surveyed the Morris area’s alternative energy resources. The report pointed to opportunities for making biogas from abundant local livestock manure. A biogas utility would be a good fit for a city, the report suggested, because cities have access to economic-development grants, low-interest loans and other public financing, which could help the economics pencil out.

Renewable energy could also be a selling point for cities trying to attract new manufacturing. When the ethanol plant in Morris expressed interest in buying methane, “we decided we should pursue it,” Larson says.

Anaerobic digesters have long been used in Europe and Asia. But in this country, cheap fossil fuels have discouraged using digesters to make renewable fuel. However, Cecil Massie predicts that rising natural gas prices and increasing world demand for electricity will make biogas generation more attractive.
 

The technology is beginning to interest large-scale livestock farmers, says Massie, who reports that at least 18 commercial-size digesters are under construction on Midwest farms. For livestock growers, Massie says, the benefits include reduced manure odors and more useful fertilizer. Research suggests that anaerobic digestion makes the nutrients in animal waste more accessible to plants, he says.
 

Just as important, Massie adds, biogas offers farmers the chance to harvest what he calls a third crop: not only food and fiber, but fuel. ■