Correction Appended: October 30, 2008
Wasting energy is so 20th century. Power is all around us, if we just know how to use it. That's what motivated Max Donelan, a kinesiologist at Simon Fraser University, to invent a device that harnesses the energy of walking. The 3.5-lb. device wraps around the wearer's knee and generates power using the same principle that allows hybrid cars to recycle energy created by braking. A walker wearing harvesters on both knees could generate about five watts of power enough to charge 10 cell phones without hampering his or her stride. Donelan's device is perhaps the most promising in a class of products that harvest energy all the more important at a time when portable tech, from Blackberries to iPods, is becoming ubiquitous. There's not a watt to waste.
The original version of this article misidentifed the device invented by Max Donelan as a Biochemical Energy Harvester when it is in fact a Biomechanical Energy Harvester.