Elon Musk built the world’s biggest battery–in just two months

Elon Musk kept his promise: The SolarCity chairman successfully built the world’s biggest lithium-ion battery in South Australia–ahead of schedule.

In July, Tesla and French renewable energy company Neoen were awarded the contract to help the country deal with its energy problems following a 2016 statewide blackout.

The Tesla founder was so enthusiastic about the effort that he even tweeted this summer, “100 days from contract signature or it’s free.”