A system that can deliver power to devices without the need for wires has been shown off at a hi-tech conference. The technique exploits simple physics and can be used to charge a range of electronic devices over many metres.
Eric Giler, chief executive of US firm Witricity, showed mobile phones and televisions charging wirelessly at the TED Global conference in Oxford.
He said the system could replace the miles of expensive power cables and billions of disposable batteries.
"There is something like 40 billion disposable batteries built every year for power that, generally speaking, is used within a few inches or feet of where there is very inexpensive power," he said.
Trillions of dollars, he said, had also been invested building an infrastructure of wires "to get power from where it is created to where it is used."