The world's biggest battery was officially launched in Australia on Friday, a day after the Elon Musk-driven project was powered up early to meet demand amid a bout of hot weather, officials said.

Musk's Tesla built the Powerpack system, which can provide electricity for more than 30,000 homes, to ease South Australia's energy woes after the state was hit with a total blackout in 2016 following an "unprecedented" storm.

The maverick billionaire earlier this year offered on Twitter to build the battery farm, and completed it last week to narrowly beat his self-imposed deadline of having it ready in 100 days.

"South Australia is now leading the world in dispatchable renewable energy, delivered to homes and businesses 24/7," state Premier Jay Weatherill said Friday at the launch to coincide with the first day of summer.