Catching Power From the Sky

As people wearing tinfoil hats can tell you, the air around us is full of signals. In the future, we’ll be able to capture some of that energy — in the form of Wi-Fi signals, vibration, heat and sound — and convert it to usable electric power. The principle here is as old as the very first radios, which ran on nothing but the power that came from the transmitter tower, but changes in materials have made it more efficient.

Early applications will be for low-power sensors in remote locations that can collect power all day long, then send out information about what they’re monitoring (temperature, location, structural integrity) in a quick burst once they’ve accumulated enough power. Highway departments could get updates on sensors mounted all over bridges, checking for sag and other defects, without the need to replace batteries or rely on access to daylight for solar power.

But the idea of finding power in the air for consumer devices such as mobile phones is the Holy Grail for vendors of this equipment. Currently, power demands of phones and the like are too high, and the amount of energy that can currently be captured is too low.