In India's Rice Belt, 350 million people live without reliable electricity. But they do have lots of rice — and rice husks discarded from harvest. So University of Virginia business students Chip Ransler and Manoj Sinha recently devised a way to give them their own form of energy independence by turning husks into biogas, which fuels mini power plants. Hundreds of homes in five rice-growing communities now have affordable power. And the ash from generating the gas isn't wasted: It can be used as fertilizer or as a low-cost ingredient for cement. With 125,000 Indian villages lacking power, "there's a lot of work to be done," says Ransler. In the next 18 months, Husk Power hopes to light up 100 more of them.
A version of this article appeared in the December/January 2009 issue of Fast Company magazine.