Page last updated at 09:20 GMT, Friday, 22 August 2008 10:20 UK

An end to spaghetti power cables

By Maggie Shiels
Technology reporter, BBC News, San Francisco

Intel forum
WREL could mean batteries being recharged within a couple of feet

Say goodbye to the tangle of cables and the wall socket and hello to powering up your electronic gizmos wirelessly.

This picture of a world without wires is one long dreamed of and came a step closer following significant progress made by Intel.

It said it has increased the efficiency of a technique for wirelessly powering consumer gadgets and computers.

"The notion of disappearing energy sources is a powerful one," Justin Rattner, Intel technology boss, told the BBC.

"Wouldn't it be fantastic if we didn't think about where the power was coming from and the power was everywhere?" he said. "No cords, no batteries anymore."

Mr Rattner envisaged a scenario where a laptop's battery could be recharged when the machine gets within several feet of a transmit resonator which could be embedded in tables, work surfaces, picture frames and even behind walls.

Intel's technology relies on an idea called magnetic induction. It is a principle similar to the way a trained singer can shatter a glass using their voice; the glass absorbs acoustic energy at its natural frequency.

At the wall socket, power is put into magnetic fields at a transmitting resonator - basically an antenna. The receiving resonator is tuned to efficiently absorb energy from the magnetic field, whereas nearby objects do not.

Light bulb moment

Intel's demonstration has built on work done originally by Marin Soljacic, a physicist at Massachusetts Institute of Technology (MIT).

At the Intel Developer Forum in San Francisco, researcher Alanson Sample showed how to make a 60-watt light bulb glow from an energy source three feet away.

WREL wastes scarcely more electricity than some computer power supplies

This was achieved with relatively high efficiency, only losing a quarter of the energy it started with.

In early experiments the MIT team lit their light bulb from seven feet away with larger charging coils and scoring an efficiency rate of between 40-45%.

This meant most of the energy did not make it to the light bulb. MIT has since improved its system to 90% efficiency at the three feet range.

'World changing'

Intel has called the system WREL, a wireless resonant energy link while MIT named it WiTricity - a combination of wireless and electricity.

Professor Soljacic, who does not work with Intel, said he was nonetheless pleased that the world's biggest computer chip maker is getting behind the technology.

He told the AP news wire "For me it's like a confirmation that it's so exciting. It's something people would like to have.

plug overload
Intel hopes its WREL technology will cut the last link to the power cord

"Now the question is if it's feasible or not. It's exciting that they're also inspired and it seems closer to reality every day."

Intel researcher Mr Sample told the BBC, "The next stage we are thinking about is to wirelessly recharge devices like laptops and cell phones so we are shrinking the size of the coils down to the size of laptops.

"The coils would be embedded in a monitor or a picture frame or desk. It's really compelling for the mobile device where you would be able to recharge your device as you enter one of these areas."

"This is a potentially world changing event," said analyst Rob Enderle of Enderle Group.

"This is the closest we've had to something being commercially available in this class."

Mr Rattner admitted the technology is at least five years away, if not more, of becoming a reality.

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