The Tesla Powerwall is essentially a giant lithium-ion battery pack, designed to store solar energy, and provide a back-up power system for blackouts or during times of low power generation.
Unveiling the system, Tesla CEO Elon Musk said that the system would be able to power entire homes and businesses for short periods, and would be the first step towards a genuinely transformed energy grid. The units had the potential to be "a critical step in this mission to enable zero emission power generation", Tesla said in a statement."With Tesla Energy, Tesla is amplifying its efforts to accelerate the move away from fossil fuels to a sustainable energy future with Tesla batteries," the company said, "enabling homes, business, and utilities to store sustainable and renewable energy to manage power demand, provide backup power and increase grid resilience."The Powerwall system will initially come in two sizes -- a 7kWh model ($3,000 or £1,949) and a 10kWh version ($3,500/£2,274). Both are internet-connected, and small enough to hang on a garage wall, and will only be enough to run a house for a few hours at a time, but will automatically recharge when connected to a power source and when not in use. The idea is that the batteries will provide an ever-present, reliable backup, and help individuals rely increasingly on solar power and other zero emissions systems rather than fossil fuel plants.
Musk also unveiled the "Powerpack", a larger system of 100kWh designed to allow cities and towns to store and distribute power over time. The design helps solve an obvious issue with solar power, which is that more power is needed at night -- precisely when less power is being generated. Many other companies are attempting to solve this problem, and solutions for both home and civic use have been proposed in several forms. Tesla says its experience building batteries for electric vehicles gives it an advantage, however, and the relatively low cost of the Powerwall should prove attractive to early adopters.
Tesla said the batteries will be built first at its California factory, but will eventually be made at its new "gigafactory" in Nevada, when it opens in 2017. "Tesla is not just an automotive company, it's an energy innovation company," it said. "Tesla Energy is a critical step in this mission to enable zero emission power generation."