http://www.bbc.co.uk/news/technology-34401616 "Free energy from the air. It sounds like a fantasy but that is what the entrepreneur and former science minister Lord Drayson has just unveiled at London's Royal Institution. The technology involves harvesting radio frequency energy from existing wireless and broadcast networks, from 4G to digital television. Lord Drayson says it's a world first: "It doesn't require any extra infrastructure, it doesn't require us to transmit any extra energy, it's recycling the energy which isn't being used at the moment."" With a bit of luck, we'll be able to suck up all the juice destined for mobile phones and walk down the street without fear of being bumped into again.