Tesla Motor (www.teslamotors.com), the electric-car manufacturer, has unveiled what it describes as a ‘home battery’ that can store power from solar panels or from the electricity grid at night to provide a secure back-up in the case of a power cut.

Speaking to reporters at the product launch in a Los Angeles warehouse, where examples of the Tesla Powerwall device were displayed on a wall, company founder Elon Musk said: “It looks like a beautiful sculpture.”

Mr Musk said that the lithium-ion battery-powered Tesla Powerwall, which is intended to fit on the wall of a garage or inside a house, “could transform the entire energy infrastructure of the world to zero-carbon.

The battery can provide financial savings to its owner by charging during low-rate periods, when the demand for electricity is lower, and discharging during more-expensive periods, when the demand is higher.”

The device — about 6in thick, 4ft tall and 3ft across — will cost $3,500 and will go on sale in the USA this summer.

The intention is to ‘roll it out’ internationally next year. “Germany is seen as a significant market for the product, as it has one of the world’s highest take-ups of solar energy.”

The billionaire entrepreneur added that he intends to create a larger version — the Powerpack — for business use.