The Toronto Zoo has a solution to global warming: elephant dung, according to Reuters. Canada's biggest zoo is inviting bids for a gasification plant that will turn its elephant, rhino and other large animal manure into clean electricity and heat. "No other zoo in the world is doing this," zoo conservation program head Dave Ireland said on Wednesday. The zoo produces about 1,000 tonnes of manure and other organic waste each year. This will be fed into the biogas plant, to be built on land adjoining the zoo, where bacteria will munch through the waste and excrete methane gas. Leftover heat will be piped to the zoo to warm buildings and animal pavilions. Ireland expects this to substantially reduce the zoo's natural gas bill of C$1.4 million ($1.3 million) a year. Zoo waste will make up only a portion of the fuel needed by the 3 to 5-megawatt biogas facility, which will generate enough heat and electricity to power 5,000 homes. The rest will come from organic waste from restaurants, grocery stores and other industrial sites in the area.