A Chinese dairy farm is installing the world's largest system to turn steaming cow pats into enough electricity to power thousands of homes.

The device at the Huishan Dairy is 10-times bigger than similar systems and will take the excrement from 60,000 cows and capture methane from the fermenting pats, according to Technology Review magazine.

It will generate almost six megawatts of electricity - enough power for 3,500 American-size households, but could service many more houses in China, which consume less energy.

The dairy, based in the Liaoning province in north-east China, imports 3,000 cows from Australia every month just to sustain its massive stock of 250,000 cows.

The magazine quoted Professor Ann Wilkie from the University of Florida as saying the project could draw attention to the possibilities of biogas.

"It shows this is not a phantom technology we have to wait for in the future," she said.

"It's something we can do now to deal with existing waste, and garner renewable energy."

China's rapidly growing dairy farming industry is a major new source of greenhouse-gas emissions.

But Huishan's new system will prevent methane, which is 23 times more potent than carbon dioxide as a greenhouse gas, from reaching the atmosphere.

It will also reduce waste and odours, and produce a valuable organic fertiliser that is safer than raw manure.

China has become the biggest source of the greenhouse gases blamed for global warming and the government has embarked on a huge program to develop renewable energies such as hydroelectric, wind and other power sources.

The Chinese government estimates that millions of small farms already have primitive manure digesters, according to the publication.

(c) 2010 AFP