Wireless Power Transmission

Wireless power transmission has been a dream since
the days when Nikola Tesla imagined a world studded
with enormous Tesla coils. But aside from advances in
recharging electric toothbrushes, wireless power has so
far failed to make significant inroads into consumer-
level gear.
What is it? This summer, Intel researchers
demonstrated a method--based on MIT research--for
throwing electricity a distance of a few feet, without
wires and without any dangers to bystanders (well,
none that they know about yet). Intel calls the
technology a "wireless resonant energy link ," and it
works by sending a specific, 10-MHz signal through a
coil of wire; a similar, nearby coil of wire resonates in
tune with the frequency, causing electrons to flow
through that coil too. Though the design is primitive, it
can light up a 60-watt bulb with 70 percent efficiency.
When is it coming? Numerous obstacles remain, the
first of which is that the Intel project uses alternating
current. To charge gadgets, we'd have to see a direct-
current version, and the size of the apparatus would
have to be considerably smaller. Numerous regulatory
hurdles would likely have to be cleared in
commercializing such a system, and it would have to
be thoroughly vetted for safety concerns.
Assuming those all go reasonably well, such receiving
circuitry could be integrated into the back of your
laptop screen in roughly the next six to eight years. It
would then be a simple matter for your local airport or
even Starbucks to embed the companion power
transmitters right into the walls so you can get a quick
charge without ever opening up your laptop bag.