This California Dairy Farm’s Secret Ingredient for Clean Electricity: Cow Poop

It has already proven its worth as a fertilizer and building material, and even as a secret ingredient in Ancient Egyptian ceramics. As it turns out, cow dung might also have a bright future as a plentiful source of clean electricity, thanks to the planet-warming methane it produces.

Few places encompass this potential future better than Bar 20 Dairy, a dairy farm in Kerman, California, which uses methane from cow manure to produce clean electricity with almost zero carbon emissions. It’s the first dairy farm in the U.S. to power its own clean energy “microgrid” using a biogas, and it could be a tantalizing sign of what the future of green energy might look like for companies with access to plenty of methane.

The technology isn’t all that hard to grasp. Manure and waste water from the farm’s nearly 7,000 cows are transported and sifted into a 25-million-gallon rectangular pit in the ground called a digester. The liquid sits for about 30 days while methane gas rises to the top of the closed digester. The gas then gets piped into a skid shifter, which separates the methane from hydrogen sulfide and other impurities. Finally, the methane is piped into fuel cells that harness it to produce electricity with little to no greenhouse gas emissions.

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This is where fuel cells lend a helping hand, since they don’t spew out carbon dioxide as a byproduct when running the methane-to-electricity reactions. Bar 20 Dairy uses solid oxide fuel cells made by San Jose-based company Bloom Energy. They consist of an anode, a cathode, and an electrolyte that’s sandwiched between two interconnected plates. As methane flows through the anode side and air passes through the cathode side, it causes a chemical reaction in the electrons which produces electricity, with practically zero carbon dioxide byproduct.

The result is a self-sustaining, clean energy microgrid: something Bar 20 Dairy’s Steve Sheheady and his family have been trying to establish for years.

Sheheady, whose grandfather started Bar 20 Dairy, told The Daily Beast the farm’s microgrid (bolstered by solar panel arrays) is running better than expected. The fuel-cell system, which started operating in October, is expected to produce about 8.5 million kilowatt-hours of power per year, which is equivalent to powering over 750 homes, according to Bloom. Right now, the farm is basically making more power than it’s able to use. Excess power is put back into the local utility’s grid and is used for electric-car charging, according to Sheheady.

Please click on: Milking a Cow for All It’s Worth