He calls it "cow power to horsepower." Leonhardt says the challenge is to cost-effectively remove impurities from the manure-derived methane.

VOA: standard.2010.02.23

Manure from about 1,000 cows goes in one end and then, controlled decomposition yields methane gas at the other.

VOA: standard.2010.02.23

The technique was taught by aid workers who also showed the farmers how to fertilize with compost or manure.

VOA: standard.2009.12.10

(SAYING) He says he tells his students that they should use manure, which feeds the plants, but does not stop there.

VOA: standard.2010.04.01

Five years ago, dairy farmer Darryl Vander Haak flipped the switch on the first electric generator in Washington State powered by manure.

VOA: standard.2010.02.23

The raw material for the digester comes from livestock waste that might otherwise end up in a smelly manure lagoon on the farm.

VOA: standard.2010.02.23

They spread the manure and watch the plants grow with nothing but the manure.

VOA: standard.2010.04.01

I've been trapped by manure semis on back road."

VOA: standard.2010.05.06