The concept of wireless power transmission is a relatively old one.  In the 1890s, Nikolai Tesla was successful in illuminating incandescent light bulbs with wirelessly transmitted power.  However, for decades this research lay dormant and untouched.

With modern telecommunications and interest in signals at an all time high, interest in the topic again picked up.  The Massachusetts Institute of Technology, in particular, developed some intriguing technology that WiTricity would later be founded upon.

Eric Giler, CEO of WiTricity says that power transmission over several feet is an obtainable feat.  He states, "Five years from now, this will seem completely normal.  The biggest effect of wireless power is attacking that huge energy wasting that goes on where people buy disposable batteries.  [And] Electric cars [are] absolutely gorgeous, but does anyone really want to plug them in?"

WiTricity isn't the only player in this new market, though.  Several key technologies, each championed by different companies, are emerging.

One is radio power.  Though only able to transmit small amounts of power, this approach can work over a long distance.  A Pittsburgh, Pennsylvania, company called Powercast is among the pioneers in this field, using its technology to power temperature sensors in large office buildings and to power wireless Christmas trees (sold for $400 a piece).  The company has lit up an LED with radio signals from 1.5 miles away.

Another approach is power pads.  Advantages include low costs and relatively high efficiencies.  Disadvantages include the extremely short distance and need for custom shapes and sizes of pads.  This technology currently is employed in the Palm Pre's recharging stone and in electric toothbrush recharging stands.

WiTricity's technology works on a third type of transmission -- magnetically coupled resonance.  Similar to sound waves, the transmission creates a magnetic field, that devices can convert locally to electricity.  This technology enjoys a middle ground with a bit worse efficiency, a bit longer distance, and moderate costs.  Intel is also working on a more efficient version of this approach.

Despite WiTricity's optimism about its new approach, challenges remain.  A full deployment is estimated to possibly create a magnetic field as strong as the Earth's own magnetic field.  According to recent research, referenced by Menno Treffers, chairman of the steering group at the Wireless Power Consortium, such a strong magnetic field can cause serious health risks.