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
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
technology that WiTricity would later be founded upon.
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
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.
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
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.
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.
quote: Too bad the Defense Department grabbed all of Tesla's work and it has set us back this far. The ideal use of his power transmission would be to generate solar/wind/geothermal power in very remote areas/deserts, middle of the ocean, etc and transmit it back to urban areas. Of course the fear of such power transmission becoming a deathray is what got this work locked up originally. Google Tesla and deathray and all kinds of information comes up. Amazing guy WAY ahead of his time...
quote: If I recall correctly you can build a "wireless" fluorescent lamp fixture using inductance. The light fluoresces due to the presence of the magnetic field. This was a popular demo in Tesla's day and is still occasionally used for science demos.