The Livestock Power Mill is an invention from William Taylor of Northern Ireland that produces electricity when cows walk on its treadmill belt while eating. The May 2010 Popular Science features a short article titled "The Energizer Cow" that details the power-producing invention.
A cow is placed on a non-powered inclined belt and will slide downhill if it doesn't walk forward. When the cow does walk forward, the belt turns, spinning a gearbox that drives a generator to produce electricity. A feed box at the front of the Livestock Power Mill lures the cow to keep moving.
A one-cow prototype can generate two kilowatts of power, enough for four milking machines. A 50-cow Livestock Power Mill system has a break-even term of three years and may also reduce bovine methane emissions.