A man herds dairy cows in the city of Totoras, 360 km (224 miles) north of Buenos Aires, in this February 1, 2012 file photo. Argentine scientists have found a way to transform the gas created by the ... more 
A man herds dairy cows in the city of Totoras, 360 km (224 miles) north of Buenos Aires, in this February 1, 2012 file photo. Argentine scientists have found a way to transform the gas created by the bovine digestive system into fuel, an innovation that could curb greenhouse gases that cause global warming. Using a system of valves and pumps, the experimental technique developed by Argentina's National Institute of Agricultural Technology (INTA) channels the digestive gases from bovine stomach cavities through a tube and into a tank. Each head of cattle emits between 250 and 300 litres of pure methane a day, enough energy to keep a refrigerator running for 24 hours. REUTERS/Enrique Marcarian/Files (ARGENTINA - Tags: AGRICULTURE ANIMALS ENERGY ENVIRONMENT SCIENCE TECHNOLOGY) less 
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Reuters | Photo By ENRIQUE MARCARIAN / REUTERS
Mon, Oct 21, 2013 1:57 AM EDT