Billionaire Elon Musk will help South Australia build the world's largest lithium ion battery.
His American company Tesla will work with French Neoen and its Hornsdale Wind Farm to install it before summer.
CEO Musk has promised to deliver the battery within 100 days or it's free.
That 100 days will begin when the grid interconnection agreement is signed.
The State Government hopes the 100MW/129MW battery will make South Australia a leader in global energy storage technology.
It'll operate around the clock to stabilise renewable energy and will be available as a back-up to help avoid a repeat of last September's state-wide blackout.