The power of Manure

20 Oct 07 | Bio Gas, Commentary, Environment

I have a friend who has a house in Burlington, VT. A few days ago he was telling me about a farm where all the cow manure is collected and held in an anaerobic digester to create methane gas (CH₄) which is then burned by electrical generators and fed into the power grid. I found this article which talks about it a little more:

Seven-hundred St. Albans cows will make more than milk today–they’ll make electricity.

“Cow Power is an opportunity for farmers to significantly reduce their environmental impact while creating clean, renewable energy. Like the emergence of automated milking and the bulk milk tank decades ago, CVPS Cow Power has the potential to change the way Vermont dairy farms do business. This will make our farm stronger.”

–David Montagne, Farm Owner
The Dave and Cathy Montagne Farm will become the latest to join the CVPS Cow Power program today, generating electricity from cow manure and helping to solve numerous environmental challenges in the process. They have the capacity to handle manure from up to 1,200 cows.

The farm produces over 15 million pounds of milk a year, and is expected to produce 1.4 million kilowatt-hours (KWh) of electricity a year.

To create energy, manure and other agricultural waste are held in a sealed concrete tank at the same temperature as a cow’s stomach, 101 degrees. Bacteria digest the volatile components, creating methane and killing pathogens and weed seeds. The methane, which is roughly 20 times more harmful than carbon dioxide in trapping heat in the atmosphere, fuels an engine/generator.

CVPS customers can choose to receive all, half or a quarter of their electrical energy through Cow Power, and pay a premium of 4 cents per KWh. It goes to participating farm-producers, to purchase renewable energy credits when enough farm energy isn’t available, or to the CVPS Renewable Development Fund. The fund provides grants to farm owners to develop on-farm generation. Farm-producers are also paid 95 percent of the market price for all of the energy sold to CVPS.

“Cow Power is an opportunity for farmers to significantly reduce their environmental impact while creating clean, renewable energy,” farm owner David Montagne said. “Like the emergence of automated milking and the bulk milk tank decades ago, CVPS Cow Power has the potential to change the way Vermont dairy farms do business. This will make our farm stronger.”

This is really a great way to handle several problems. Methane is 20 times the greenhouse gas that CO2 is. Since all cows produce manure, and all manure produces methane when it breaks down, this is one very effective way of eliminating agricultural greenhouse gas production.

Even if the methane was simply burned it would help reduce greenhouse gas emissions. The fact that it is used to turn a generator and thus eliminate some of the electrical load makes it even more attractive. By the way, almost any gasoline engine can burn methane with a few simple modifications, which means that this could type of system could power cars, light trucks, etc.

For the farmer, the problem of getting rid of the manure is taken care of. After anaerobic digestion, all that is left is a brownish black nitrogen rich crumbly substance that can be used to compost gardens and lawns.

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