Cow pie energy studied by Fort Collins firm

FORT COLLINS – Forbes Guthrie surveys the dairy industry landscape in Northern Colorado and sees a possible energy-producing engine that could also reduce the amount of harmful emissions floating up into the atmosphere.

And the source of that energy?

Cow pies.

Guthrie, director of business development for Stewart Environmental Consultants Inc., says the region’s vast and growing dairy herds could be a potential source of biogas produced by feeding an unending supply of manure into shared anaerobic digester systems.

“There’s over 100,000 dairy cattle in Morgan and Weld counties,” Guthrie said. “And there’s going to be even more with Leprino moving into Greeley. This area is one of the top producers of dairy products in the United States.”

Milk and ultimately cheese are the primary products of these dairy operations, but Guthrie notes that the byproduct of manure – typically spread onto fields as crop fertilizer – could be better utilized for the energy potential within it.

“It’s a travesty to just land-apply that stuff because it has a lot of potential energy,” he said.

Methane gas emitted from raw manure is about 20 times more harmful than carbon dioxide, the most common form of the so-called greenhouse gases believed to be responsible for global warming. Guthrie said running the manure through an anaerobic digester can reduce that effect dramatically. “There’s the potential to offset a lot of methane and to turn the end product into a usable good.”

Study grants awarded

That’s why Stewart Environmental was awarded a couple of grants from the Colorado Department of Agriculture to determine the feasibility of using anaerobic digesters to generate burnable biogas from dairy cattle manure.

In late December, Stewart Environmental was awarded a $50,000 grant from the state’s Advancing Colorado’s Renewable Energy, or ACRE, program. Fort Collins-based Stewart Environmental had earlier received a $25,000 ACRE grant to begin the feasibility study.

The current phase of the study is conducting an inventory of available organic materials in the region. Guthrie said Stewart Environmental is focusing on confined dairy feeding and milking operations that could produce enough manure to make collective ownership of an anaerobic digester system affordable and even profitable.

So far, Stewart Environmental’s research has shown that the smallest feasible concentration of dairy cows for a regional digester would be 5,000 head within a two-mile-or-smaller radius due to transportation costs. The company determined there are six such locations within Weld and Morgan counties.

The cost of a digester – beginning at about $1 million – is prohibitive to an individual dairy operator and only a collective use of the device would make it affordable. “The big opportunity is to take a look at the shared economics of the larger digestive system,” Guthrie said.

Potential benefits to dairy producers include a reduction in on-site manure odor and methane emissions and a biogas that could produce electricity for on-site operations and possible sale to the electric grid.

“The hydrogen and the methane produced can co-generate (biogas) on site to heat boilers, create electricity on site, or – if there’s enough – be used to power turbines and put electricity on the grid, or clean the gas and put it into a pipeline,” Guthrie said.

Les Hardesty, owner of Cozy Cow Dairy near Windsor and former president of Dairy Farmers of America, said he thinks dairy operators would “absolutely” be interested in such a concept. “You think about sustainability and being earth-friendly,” he said. “We have an energy source – continually produced – that can be converted fairly easily into gas or electricity. I think it’s exciting.”

Carbon offset incentive

Guthrie notes that another possible incentive for dairy producers is the potential sale of carbon offset credits to companies wishing to reduce their carbon footprint. Susan Innis, program manager for the Colorado Carbon Fund program under Gov. Bill Ritter’s Energy Office, said reducing emissions through the use of anaerobic digesters is a goal of Ritter’s New Energy Economy philosophy.

“We’re definitely interested in anaerobic digester technology,” Innis said. “The Colorado Carbon Fund is very interested in purchasing offsets from projects like that.”

Guthrie said while there are numerous examples of biogas facilities in Europe and Scandinavia producing electricity and heat, the idea is just beginning to catch on in the United States. One company, Texas-based Microgy, has eight 900,000-gallon digesters that can produce 2,000 million BTUs of renewable natural gas daily at its Huckabay Ridge Facility, one of the largest in the world.

Guthrie said the next step toward creating a Northern Colorado dairy-based anaerobic digester facility is to find a group of dairy operators willing to participate in a pilot project.

A report prepared by Stewart Environmental for the Colorado Department of Agriculture calls for an initial investment of $8.2 million, which would include a fleet of vehicles to transport manure and byproducts. A model based on that investment projects annual revenue of $2.5 million and a payback of less than six years.

Guthrie notes that a pilot program is needed to see if those projections can be met. “Does it really work in real life with all of the atmospheric variables? That’s the million-dollar question.”

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