Laser Beams Of Wireless Power
Another safe way of transmitting power is to convert it to optical energy, or a laser beam. That’s a well-known technology and there are plenty of components on the market, so building devices is more a problem of convincing major manufacturers to use the system. PowerBeam sends a collimated 1400nm laser beam with up to 5W of power as far as 40 meters across the room, and the receiver sends back a much lower power beam to send information (you won’t see either of them, although the receiver you stick on the wall has a low-power red laser, like a laser pointer, to align the units).
You do lose a lot of the power that goes into the system by converting back and forth; the maximum efficiency to start with will be 35%, but the lights, security cameras, speakers and smoke detectors PowerBeam expects to run with the first devices are often only 10-30% efficient when you run them from a wall plug anyway. “You’re not going to run a plasma TV off this, it would be too expensive,” admits CEO David Graham, “but for anything up to 10W, you won’t notice it on your bill.” Increasing power efficiency in lots of consumer electronics means that 10W is enough to power a lot more devices; a 6 or 8W LED bulb gives you the same illumination as a 25W CFL bulb.
The big advantage of PowerBeam is that you can put power in places that you normally wouldn't due to the inconvenience; hanging digital picture frames on the wall or saving power with sensors, for example. “With an occupancy sensor in the corner of each room and a wireless thermostat, when no-one is home you can turn off the heating, the ventilation, any lights that are on… but it won’t work if those devices have a battery that only lasts a year.”
Initially, adding wireless power to a device might put an extra $50 to $100 on the price tag, but in few years that will drop to around $20, Graham predicts. He also plans to bring out 1W and 10W systems for specific products.