Electricity for all

Perham, Minn. — Dairy farm wastes could someday heat homes and dry clothes for residents of a northern Minnesota town.

That’s according to Little Pine Dairy owner Ron Tobkin, who hopes a feasibility study will show that energy produced by a methane digester on his 1,200-head operation is economical as well as environmentally friendly.

Tobkin has designed a city-rural cooperation scheme where, besides dairy manure, a digester would convert waste from one of the city’s biggest employers, Barrel O’ Fun, into energy. Primera Foods, another Perham business, has also expressed interest. Waste diverted to the digester would ease burdens on the city’s wastewater handling system, Tobkin says, allowing industry to expand. Perham could sustain more jobs without increasing its wastewater treatment capacity.

“Pulling together, it’s the way of the future,” Tobkin says. “We’re looking for ways that the agriculture industry and communities can work together to add value to waste products.”

If the digester is built, Tobkin says, it would hold 20 days of waste products — about 1 million gallons — with expansion capability. Project costs are estimated at $1 million. Funding could come from the dairy, rural utilities and state and federal aid, Tobkin says.

More steady than the wind

Energy from dairy farm byproducts is “more reliable than wind energy,” Tobkin says. “It’s seven days a week, 24 hours a day.” Little Pine Dairy spends more than $100,000 a year for electricity; using power from the methane digester would help offset that cost. Potato chip manufacturer Barrel O’ Fun spends $10,000 to $14,000 a month to haul away waste, Tobkin says, and its savings could be substantial with a digester.

AURI hired RCMDigesters of Berkeley, Calif., which has designed 30 digester systems over the past 20 years, to run the numbers and see if a digester using agricultural and industrial waste is economically feasible. Other Minnesota communities have contacted AURI for similar information, says Michael Sparby, AURI program director in Morris.

“If you are able to negotiate a favorable rate on a per-kilowatt hour, it’s feasible,” Sparby says. Tipping fees — the money companies spend on hauling away waste — can also be diverted to the digester, offsetting costs. Another revenue source could be the methane gas by itself, Tobkin says; gas lines already run to his farm. His vision includes “scrubbing methane and pumping it back into the city’s lines.”

An electric utility has to pay around six cents per kilowatt hour to make the project work, Tobkin says. One Minnesota dairy farm near Princeton sells methane digester-generated electricity to a power company (see Ag Innovation News, July 2001). At 7.25 cents per kilowatt hour, owners Dennis and Marsha Haubenschild earn an average of $900 a week on electricity sales.

Aroma of approval

An added benefit is a reduction in waste odor, Tobkin says. Solids remaining after the digestion process have “very little if any odor.” Further drying renders a pathogen-free matter that can be used as fertilizer or even bedding. “We don’t lose the nutrient value of nitrogen, phosphorus and potassium; we’re able to retain that.”

The community digester has the support of the City of Perham, U.S. Rep. Collin Peterson, the Minnesota Pollution Control Agency and the East Otter Tail Soil and Water Conservation District. There is also interest in the digester as a pilot for Project Minnesota, a rural economic development organization, Tobkin says. “This is an excellent example of how the City of Perham, Barrel O’ Fun, Primera Foods and Little Pine Dairy can all win,” Perham city manager Robert Louisseau wrote in a project support letter.

For more information on methane digester economics, see “A Self-screening Assessment and Checklist,” on the Web at www.auri.org/research/digester/digchck.htm