Electric power generation from walking

Last month, the journal Science reported that a Swedish company was planning on using the body heat generated by commuters in a Stockholm train station to warm a nearby office building. If that sounds too…personal, they're not the only ones thinking about ways to reuse wasted energy. A team of scientists from Ann Arbor, Pittsburgh and British Columbia have come up with a way to tap pedestrian power. They've created a device, which straps onto your knees, that can harvest energy from your stride the same way hybrid electric vehicles recycle power during braking.

Their report, which appears in the February 8 issue of Science, shows that walkers can generate about five watts of power without so much as breaking a sweat. That's enough energy to run 10 cell phones or two computers at once, which could be good news for people who live in countries where access to electricity is spotty. The bad news is: the device could enable commuters to talk on the phone, listen to music, email their friends, play video games, check their stock quotes, and photograph themselves doing it, just by pacing back and forth waiting for their morning latte.  We beseech them not to—on  bended knee.