Cow Power: The Next Renewable Resource

Strange, new power plants are popping up in places like Vermont, California and Wisconsin. These power plants do not burn coal, instead they are fueled by methane, obtained by heating cow manure. "Cow power" is becoming popular because it provides another income source for farmers, as well as reducing the environmental impact of farms by harnessing the methane that would otherwise act as a greenhouse gas. According to the United Nations, cattle are responsible for 18% of greenhouse gases worldwide.

The entire process can be broken down into just a few steps. Manure is first transported to an anaerobic digester which heats the manure to about 100 degrees, and with the help of bacteria, releases large amounts of methane and other gases from the manure. These gases are piped to a modified natural gas engine, which burns the methane to power a generator, creating electricity. Excess heat from the engine is used to keep the digester warm.

After the manure is fully digested, it is germ-free and odorless. The process also kills the seeds of weeds, preventing the spreading of them to the farmer's fields. The manure can be separated into solid and liquid components. The solid can be used as bedding for the cows, eliminating the need for farmers to buy sawdust for this purpose. This can save a large farm thousands of dollars every week. The liquid manure can be used as fertilizer on the crop fields, as is typically done.

A single cow can create a staggering 30 gallons of manure a day, so the output of only 5-10 cows can power an average American home. With the number of cows in the USA coming in at over 90 million, anywhere from 9 to 18 million homes could be fueled by Cow Power.

Electricity customers in Vermont can choose to have some or all of the electricity for their home come from cow power. They pay 4 cents extra per kilowatt that comes from cow power, as this surcharge is paid to the farmers for the production of the power. Central Vermont Public Service, the power company that currently has six farms providing cow power to their customers, also provides grants to farmers for the initial cost of outfitting the farm with the anaerobic digester and the engine.

This process of harnessing cow power is one of the newest ways of reducing environmental impacts and dependency on non-renewable resources.