Elon Musk and Tesla have made good on an ambitious commitment, and the state of South Australia is now home to the world's biggest battery. The battery installation is connected to a wind farm (that's what gives it its juice) and the larger grid, and serves as an electricity reservoir for times when power demand peaks or the wind isn't blowing. Musk, a P.T. Barnum-like showman who recently unveiled a new electric truck and next-gen Roadster even while the company's Model 3 deliveries have been slow, had promised that the bold project would be free if they couldn't complete it in time. Now, they have.

It's fun to imagine an enormous Duracell battery sticking out of the ground, but in reality, the massive installation—it's comparable to a football field's footprint, according to The New York Times— is a network of batteries housed in Tesla-made units called Powerpacks.