Wireless “Power Harvesting” for Your Cell Phone?

Filed Under: Green Technology on June 13, 2009

Photo Credit: Technology Review

Not too long ago, I published a short piece about bendable cell phones that recharge through kinetic energy (movement) and friction (bending). That was Kyocera’s Flexible, Kinetic-Powered Smart Phone. Well, this idea is something that might do-able very soon.

Nokia has a plan to modify existing cell phone circuitry to accept and harness ambient electromagnetic radiation to keep the phone topped off and running longer. While there generally won’t be enough of this extra energy to fully charge or power most phones, there is enough to save a significant amount of wall jack plug-in time.

The idea is pretty cool and apparently very simple. Every transmitter that sends out signals creates ambient energy–the signal itself is energy, after all. So WiFi, cell antennas, TV and radio towers, etc. are all pumping out energy into the atmosphere. All a cell phone or other gadget needs to do is be wired in such a way that some of its circuitry acts as an “antenna” to receive those broadcasts and convert them into usable energy.

Remember those crystal radio sets you used to buy the kits for and build as a kid? Exactly.

That’s pretty awesome. If you live in a town or city of any size, your whole ‘urb is probably lit up with this ambient energy just ripe for the harvest.

So far, the team at Nokia, headed by Markku Rouvala at the Nokia Research Centre in Cambridge, UK, has managed to build prototypes that can harness 3 to 5 milliwatts. Their next goal is to hit the 50 milliwatt number, which is enough power to slowly recharge a phone that’s off.

The team hopes to have the new prototype by the end of the year and a possibly marketable version by 2012. Fifty milliwatts is probably the max that can be expected from this technology, most engineers and scientists seem to agree.

Still, that’s plenty to save a lot of juice coming from the outlet and power grid.

For more on this and how it works, visit a great writeup at TechnologyReview.com and the Nokia Research Centre’s website.