been able to "beam" electricity a few feet to power a light bulb, the
day when our laptops and cell phones can charge without having to plug
them in to a wall socket still seems decades in the future.
Nokia, however, has taken another baby step in that direction with
the invention of a cell phone that recharges itself using a unique
system: It harvests ambient radio waves from the air, and turns that
energy into usable power. Enough, at least, to keep a cell phone from
running out of juice.
While "traditional" (if there is such a
thing) wireless power systems are specifically designed with a
transmitter and receiver in mind, Nokia's system isn't finicky about
where it gets its wireless waves. TV, radio, other mobile phone systems
-- all of this stuff just bounces around the air and most of it is
wasted, absorbed into the environment or scattered into the ether.
Nokia picks up all the bits and pieces of these waves and uses the
collected electromagnetic energy to create electrical current, then
uses that to recharge the phone's battery. A huge range of frequencies
can be utilized by the system (there's no other way, really, as the
energy in any given wave is infinitesimal). It's the same idea that
Tesla was exploring 100 years ago, just on a tiny scale.
Mind
you, harvesting ambient electromagnetic energy is never going to offer
enough electricity to power your whole house or office, but it just
might be enough to keep a cell phone alive and kicking. Currently Nokia
is able to harvest all of 5 milliwatts from the air; the goal is to
increase that to 20 milliwatts in the short term and 50 milliwatts down
the line. That wouldn't be enough to keep the phone alive during an
active call, but would be enough to slowly recharge the cell phone
battery while it's in standby mode, theoretically offering infinite
power -- provided you're not stuck deep underground where radio waves
can't penetrate.
Nokia says it hopes to commercialize the technology in three to five years.
