In September Musk made a bet on Twitter, saying that he can solve the power problem in South Australia in 100 days, or it will be built free of charge to the state. The countdown to 100 days started on September 30. Now, after just 60 days, the project has been completed.

The 100-megawatt battery, three times more powerful than the second biggest batery in the world, was activated today. It's located near Jamestown, and is connected to a wind farm run by a French energy company.

The battery is meant to prevent incidents like the one last year when the entire state lost power. It will now be used to support existing electricity supplies and stabilise it whenever needed. But when fully charged, it can also power up to 30 000 homes for an hour.

The battery uses the same technology that also powers Tesla's cars.