Imagine not having to ever look for a phone charger or an extra battery ever again. This is the world envisioned by Dr. Matt Reynolds and the people at Powercast. The world that Dr. Reynolds dreams of might not actually be that far from reality.
Powercast is a Pittsburgh based company that specializes in finding ways to draw electrical power from radio waves. Since radio waves are all around us, this means that one day someone might be able to use a cell phone without ever having to worry about charging it, or leave clocks and radios running for decades without having them slow down or run out. At the moment, the technology has only reached a point where it can power devices that require an extremely low level of power, such as small sensors and transmitters. However, Powercast hopes that one day they can expand their market to cover much bigger appliances. The company is also working on a number of transmitters, so that you can broadcast the power frequency from one place, and then use it to power devices within a specific range. The New York Times covered a demonstration of one of the Powercast devices here.
This idea of wireless energy transfer was first explored by the Serbian scientist Nikola Tesla, a contemporary of Edison, who experimented with powering electrical light bulbs without connecting them physically to a power source, around 1900. Ironically, Tesla helped to invent the radio.