The Economist round-up various wireless electricity projects, most of which focus on “ambient” energy from “existing radio waves produced by television, radio and mobile-phone transmitters.”
The first devices to be powered entirely by ambient energy are likely to be sensors, calculators and clocks. But the hope is that music-players, e-readers and mobile phones will eventually follow, says Dr Smith. There are other means of harvesting ambient energy, from vibrations, movement or heat. But the attraction of radio waves is that they are pretty much everywhere. It’s like recycling energy, says Dr Fisher. “It’s energy that’s around, and is not doing anything else,” he says.
July 1, 2010 at 7:31 pm
Unfortunately, not very much radio energy at all (unless you build a Tesla tower ;D)
You’d have more luck harvesting from an overhead power line with a tuned coil. Bear in mind that this IS theft – at least in the UK; there was a test case a few years back now.
Vibration and heat definitely work. So do solar cells, in the right environment.
August 7, 2011 at 12:46 am
Whenever energy production and usage is spoken about, you really need to think about scale. Just because you can harvest radio waves doesn’t make it feasible or efficient. Think about the lowest power microcontrollers (which are way too weak for mobile phones, ereaders and so on). Even these require around a few mW of electricity, which you probably won’t get from radio waves. The big trade off is cost compared to payoff.