Tesla just built the world's largest battery, thanks to a bet

In July, Elon Musk bet the people of Australia he could build a 100MW battery in 100 days or it would be free.

Turns out the man who proposed using rockets to fly us around the world in 30 minutes is nothing if not ambitious. Tesla just did it -- with about 40 days to spare.

On Friday, the South Australian government announced the completion of the world's largest lithium-ion battery just outside the South Australian city of Jamestown. In a statement, the office of state premier Jay Weatherill confirmed the battery would be energised within days.

The battery was the result of a bet between Tesla CEO Elon Musk and fellow billionaire (and founder of Australian tech company Atlassian), Mike Cannon-Brookes. After a series of major power outages across South Australia, including a state-wide blackout that affected an area the size of France in September 2016, Cannon-Brookes challenged Musk to find a solution.

The deal to build the battery was struck over Twitter in March, Musk flew to Australia to announce the build in July and contracts were signed on Sept. 29, kicking off the official 100-day countdown. But by that time, Musk was hosting a party in a marquee in South Australia overlooking an already half-completed battery array.

The 100MW battery array, made up of Tesla Powerpacks, is connected to the nearby Hornsdale wind farm, operated by Neoen. Set to be launched by Tesla officially, Neoen and the SA government next week, it will then go through a testing phase to ensure it meets regulations.

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