You can almost smell the photo above: "a vat of liquid cow manure covering the area of five football fields and 33 feet deep". Ew. But as long as we are stuck with all that manure from industrial farms (and aren't using it locally like on the Polyface Farm), something might as well be done with it.
The Vintage Dairy Biogas Project, the project of dairyman David Albers, wants to provide enough natural gas to power 1,200 homes a day. "As cow manure decomposes, it produces methane, a greenhouse gas more potent than carbon dioxide. Scientists say controlling methane emissions from animals such as cows would be a major step in addressing climate change."
To tap the renewable gas from cow manure, the Vintage Dairy farm first flushes manure into a large, octagonal pit, where it becomes about 99 percent water. It is then pumped into a covered lagoon, first passing through a screen that filters out large solids that eventually become the cows' bedding. [...]
Weights on top of the digester channel the gas to the small facility where it is "scrubbed" of hydrogen sulfide and carbon dioxide. The end product is "close to 99 percent pure methane" according to BioEnergy Chief Operating Officer Thomas Hintz.
The the gas is injected into PG&E;'s pipeline, where it will be shipped to a power plant in Northern California.
There are many other manure lagoons like that one that aren't capturing the methane, so that seems like the thing to do both economically and environmentally.
A second dairy in Fresno county has already agreed to join the Vintage Dairy project and Albers estimated gas from the two dairies combined could power 2,500 homes a day.
It would probably be a good idea to start thinking about harnessing biogas from other sources as well. There's a low of cows, but there's also a lot of us. How about human sewage?
See also: ::TreeHugger Picks: Behold - The Power of Poo, ::Biogas: Poo-Powered Prison in Rwanda, ::Human Poop and Urine Provide Cheap Biogas Source in Uganda, ::Bio-Digesters in India: Nothing Wasted, A Lot More Gained