4 May 2015
South African born and raised tech entrepreneur Elon Musk at a presentation in the US on Thursday night announced the development of a new battery system that can store solar energy for later use.
The battery, known as the Powerwall, addresses a key obstacle to wider use of renewable energy sources: “The obvious problem with solar power is that the sun does not shine at night,” he said at the Los Angeles-area design studio of his electric car company, Tesla Motors.
The Tesla Powerwall is a home battery designed to store solar energy. (Image: Tesla Motors)
That means energy grids using solar power still need backup sources of electricity. In South Africa and the US, this is largely generated by power plants burning coal or natural gas.
But the batteries to be produced by the new company, Tesla Energy, are “the missing piece” to wider reliance on solar power, he said, storing energy generated when the sun shines for use when it doesn’t.
Ability to ‘power a small city’
“The goal is complete transformation of the entire energy infrastructure of the world, to completely sustainable zero carbon,” Musk told reporters.
Tesla Energy will produce batteries for residential use, and scalable battery systems with capacity up to 1 GWh that “can power a small city” like Boulder, Colorado, Musk said.
The Tesla Powerwall, stackable batteries for residential use, each with a capacity of 10 kWh, will sell for $3 500 each (about R41 500) and would be available in three to four months.
The device, which is about 15cm thick, 1.2m tall and 90cm wide, will be a boon for under-developed regions, where power is often unreliable despite abundant solar energy. “This is going to be really great for the poorest communities in the world. This allows you to be completely off-grid.”
In 2012, the average US household used about 11 380 kWh of electricity per year. German households averaged 3 413 kWh per year.
In a 2013 report, the US Department of Energy said storage “can ‘smooth’ the delivery of power generated from wind and solar technologies, in effect, increasing the value of renewable power”.
Electricity storage is “the thing that’s needed to have a proper transition to a sustainable energy world”, Musk said.
Musk runs the US’s second-largest manufacturer of solar cells, Solar City, as well as the electric car pioneer Tesla Motors and space transport producer SpaceX.