Imagine a world with no wall chargers. People power might just make that world a reality.
University of Wisconsin-Madison associate professor Tom Krupenkin told Highfield that placing a salty liquid within the soles of shoes could generate enough electricity to power many of the devices used by millions of consumers around the world.
"This is more than sufficient to power such common devices as smartphones and tablets," he said. "We expect the first product prototype to be available in one to two years."
However, don't start planning to charge your Kindle with an after-dinner walk around the block just yet. Laurie Winkless of the U.K.'s National Physical Laboratory says that piezoelectric devices could prove to be more trouble than they are worth, unless used properly. For example, "thermoelectric" clothing may be able to draw energy from the body but could leave the wearer feeling uncomfortably cold. And those saltwater shoe batteries may prove to be painful for people walking long-distances.
Still, even skeptics like Winkless see a promising future around the corner for these alternative energy generators.