Tesla, an electric car company owned by billionaire Elon Musk, will build the world's largest lithium --ion battery.
Entrepreneur Musk and Tesla's head of the battery division, Linden Ryf, have proposed to build an energy storage facility in South Australia after a storm in March 2016.
South Australia has been working in recent years to secure renewable energy supplies and retain electricity for residents.
As a manufacturer of electric vehicles, Tesla has also invested heavily in energy storage and solar panel technology.
It believes its technology can go far beyond power supply to vehicles and power grids.
Musk stressed to Mike Cannon
Brooks, an Australian entrepreneur behind American technology company Atlassian, believes Tesla has the ability to meet the energy needs of South Australia.
Musk said on Twitter that Tesla "will install the system within 100 days of signing the contract, or free of charge.
This is serious enough for you, "the deal is now agreed and will see Tesla building a 129MWh battery in Jamestown, a town with a population of less than 1,500, just over 120 miles north of Adelaide.
Musk said: "This is not a small attempt at the border . "
"South Australia is willing to do a project that is larger than any other project in the world, and I am very impressed.
"This requires a lot of initiative," he added . ".
"I do think this is something the world will look at as an example.
"The battery will be paired with a nearby wind farm operated by French renewable energy company Neoen.
It's even bigger than Tesla's 80 MWh battery farm, which was completed in just 90 days in Southern California earlier this year.
It is not clear whether Musk's Twitter has become part of the contract agreement between Tesla and South Australia.