The technology, called Freevolt, can be the power source for the “internet of things”, allowing low energy devices from wearables to sensors to operate without being plugged in. The technology involves harvesting radio frequency energy from existing wireless and broadcast networks, from 4G to digital television. Former Minister 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.”