The Next Big Thing

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Since pandas and elephants get the bulk of their nutrients from woody plants, their excrement could provide the key to cheap and effective biofuel. The feces of the two species contain the same gut bacteria that efficiently convert lignocellulose--the woody stuff in plants--to sugars. Researchers at Mississippi State University (working with pandas) and at the Dutch technology company DSM (working with elephants) say that such bacteria could be key to producing cellulosic ethanol from biomass like wood chips, switchgrass, and corn stover.

Putrefying ponds of hog excrement are one of the nation's fastest-growing sources of methane, a greenhouse gas 21 times more potent than carbon dioxide. Now Duke University and Duke Energy have teamed up to harness pig-poop power, using the methane from a 9,000-head hog farm in North Carolina to run an electrical turbine. The project, which produces enough electricity to power 35 homes, has won support from Google, which is searching for ways to offset the carbon footprint of its energy-hogging data centers.

Dried flakes of human waste fuel Thames Water, Britain's largest water and sewage company. The flakes, which resemble instant-coffee granules, are made from dehydrated sludge, the fecal goo left behind after wastewater is treated. Once dry and powdery, the stuff can be burned, providing 16 percent of the utility's energy and reducing its carbon footprint by 550 tons a year.

—Dashka Slater