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Concentration of CO2 in the Atmosphere

Cow Power in New York and Vermont

Image: pixabay.com

Evan Lawrence

In Vermont, a program that pays farmers to generate electricity from cow manure provides enough power for 3,200 homes. In New York, farmers are discouraged by low power prices that make it difficult for the expensive manure-powered systems to break even. Fourteen of Vermont’s roughly 800 dairy farms are in Green Mountain Power’s (GMP) renewable energy program, but in New York, with about 4,600 dairy farms, only a few dozen farms statewide are believed to be generating electricity with anaerobic waste digesters.

“One of the big factors is an agreement with the power company,” said Aaron Gabriel, crops and soils educator at Cornell Cooperative Extension in Washington County, N.Y. Gabriel said he knew of only two farms with digesters in his region.

Anaerobic waste digesters heat manure and other organic material in an oxygen-free tank, where naturally occurring bacteria break it down. The bacteria release methane which can be collected and burned for heat or to run a generator. Because methane is a more potent greenhouse gas than carbon dioxide, the digester greatly reduces the farm’s impact on the atmosphere.

In three to four weeks, the remaining sludge is separated into liquid and fibrous solids. The liquid can be sprayed on fields as fertilizer. The sanitary, odor-free solids can be returned to the barn as fluffy bedding or sold as nutrient-rich compost.

Green Mountain Power, the utility that delivers most of Vermont’s electricity, estimates that a digester-generator system costs around $1,400 per cow. Farmers may need loans, grants, and a good rate for the power they produce to make a system feasible. GMP customers who want to support renewable energy from anaerobic digesters pay an extra four cents per kilowatt-hour (kWh) on all or a portion of their electric bill. Farmers receive a fair market price for the electricity plus the tariff. GMP doesn’t make money on the program.

The 16-year old program includes dairy farms around the state, explains GMP spokeswoman Dorothy Schnure. She knew of no farms that have dropped out of the program. Customers include businesses, non-profits, and homes. “It’s a great success story,” Schnure said.

The Wagner farm in Poestenkill, NY installed an anaerobic digester and generator in 2010 to handle manure from its 400 cows. The farm took advantage of a state program, no longer available, that paid an incentive for power produced for three years.

Although the cost of the digester was a big hurdle, the Wagners found that learning to operate it was also a challenge. “Getting into a digester, you don’t know much about it,” said Keith Wagner, who manages the system. “There’s a large learning curve.”

In summer, the system generates excess power that the farm sends to the grid. The farm’s electrical utility, National Grid, pays only three cents per kWh, “well below market value,” Wagner said. In the winter, “we break even or spend money on electricity.” The utility was not eager to deal with the system, he said. The biggest benefit has been the bedding solids, which the cows like.

When the Wagners installed their digester, New York’s energy policy was based on standards that encouraged renewable energy development. However, that policy is under review. The state’s goal is to obtain 50 percent of its electricity and reduce greenhouse gases by 40 percent by 2030, but new policies may or may not favor the economics of digesters.

NY Assemblywoman Carrie Woerner has many dairy farms in her upstate district. She supports legislation that would require utilities to pay a fair market price for electricity from anaerobic digesters.

“Power from digesters is different from other forms of green energy,” Woerner said. Unlike solar and wind, which are intermittent and depend on weather and season, “you know how many cows you have, how much they eat, and how much they poop. You can predict very accurately how much power they’ll produce and put on the grid. They are a base producer. Utilities know how much they need to meet peak demand. If they know how much digesters are producing, they know how much less power they’ll have to buy on the open market.”

Digesters also “take methane out of the equation, which reduces greenhouse gases and produces power. I think that’s something we should be encouraging, but we’re not able to recognize the opportunity of this technology, because the Public Service Commission doesn’t require distributors to pay a fair market price,” Woerner said.

Evan Lawrence is a free-lance writer in Cambridge, NY. This article appeared in a longer form in the December 2017-2018 issue of Hill Country Observer.

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