A case study in Vermont suggests that it is economically feasible for dairy farms to convert cow manure into electricity using anaerobic methane digestion, provided there is adequate commitment from utilities, farmers, customers, and government agencies.
During a seven-year period, six dairy farms participating in the Central Vermont Public Service Corporation’s (CVPS) so-called Cow Power program were able to generate about 12 million kilowatt-hours of electricity annually, and more than 4,600 customers voluntarily paid $0.04 more per kilowatt-hour, or about $470,000 annually, to use that power, according to a study published in the Journal of Dairy Science.
“The Cow Power program represents a successful and locally sourced renewable energy project with many economic and environmental benefits,” said Qingbin Wang a University of Vermont professor and lead author of the study.
But the study found the program’s success was dependent on several factors, including the base electricity price, premium rate, government financial support, and additional revenue from the sale of byproducts of methane generation.
Article appearing courtesy Yale Environment 360.
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Integration, Displacement, Localization
The Cow Power Program in Vermont is part of an agri-biogas movement that is sweeping the country. Environmentally, the big benefit is the mitigation of methane, which is supposedly 22 times more potent than CO2. Methane is the low hanging fruit on the Greenhouse Gas Tree. So when you capture methane escaping into the atmosphere and instead use it as a fuel to generate electric power, you are also displacing another source of fuel – whatever fuel was being used to supply the local grid. Keep in mind, you’re getting this methane feedstock, dairy cow manure, ONSITE, without drilling for it or mining it, without transporting it, and without burning additional fuel and causing pollution to get it hundreds or thousands of miles to the point of use…
The other benefit is that you’re reducing manure run-off that ordinarily pollutes local streams and rivers with nitrogen-phosphorous residues, leftover after dairy cows digest their feed, which typically includes corn…
The next step is to take the leftover nutrient-rich effluent from the biogas digesters and feed it to algae or duckweed. This exploits the minerals in the effluent as a valuable resource, and converts it into a complete protein livestock feed – A high quality supplemental feed that is produced ONSITE in a closed loop system. Again, no fuel was used to extract it and ship it to the point of use. You just improved the carbon footprint dramatically – through integration, displacement, and localization.
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