Lots of solutions available depending on local needs and resources.
"Energy Conservation on the Farm at the Huls Dairy" provides information
about the operation of Montana's first methane digester for a dairy
operation. The project was a huge success and is currently producing
enough power to run the entire dairy operation and one home. The
digesters are located at the Huls Dairy Farm in Corvallis, Montana. The
video shows the digesters at work using the methane gasses to produce
energy. The video also explains other benefits from the installation of
the digesters including commercial composting, fuel, fertilizer, and
irrigation savings.
The anaerobic methane digester offsets the
electrical costs of the dairy operation and reduces greenhouse gas
emissions at the farm. Manure from the free-stall barn is collected
using alley scrapers and deposited in the methane digester. The manure
is broken down through a biological process which produces methane gas.
The methane gas is then used to power an engine and generator to produce
electricity.
https://www.youtube.com/watch?v=wVkMmUP3ei0