World powered by batteries? Elon Musk unveils plan to leave power plants redundant

Will the world become battery-powered? That's certainly the ambition of Elon Musk, the PayPal billionaire turned would-be space explorer and electric car baron.

Last week Musk unveiled what he called "the missing piece" in sustainable energy - a range of batteries that can be used in homes and businesses to store power from wind or solar or take advantage of cheap electricity to charge up overnight and then be used in peak hours.

Two billion of these "Powerpacks" could store enough electricity to meet the entire world's needs. "That may seem like an insane number," Musk said. "We're talking about trying to change the fundamental energy infrastructure of the world."

Next year, Musk's Tesla Motors is set to start operating a power-storage-device "gigafactory" across nearly a thousand acres of Nevada real estate. The company is required to contribute US$3.5 billion to the local economy, in return for a US$1.25 billion tax break.

Battery expert Davide Andrea, an engineer at Colorado-based battery manufacturer Elithion, worries about costs, with the most basic home unit priced at US$3,500. No details have yet emerged about the cost of the large units Tesla is reportedly supplying to companies including Apple and Google to help manage their power supplies.

"Electricity is way too cheap to store in an expensive battery," Andrea said. "It's like saying I'm going to be storing my potatoes in a safe. Potatoes are too cheap to store in a safe."

But Andrea is convinced batteries are part of a more energy-efficient future. He is currently involved in a new project in Boulder to install batteries in homes, to ease the strain on power plants and avoid costly rewiring as the sizes of neighbourhoods change.