In a rare move for Tesla, the company has delivered a product well ahead of its own deadline, as the world's largest lithium ion battery is installed in South Australia.

Tesla boss Elon Musk said in late-September that he would build and install the battery within 100 days, or it would be provided for free. Musk was reacting to news of widespread blackouts which had struck Australia earlier that month.

The blackouts were blamed on several factors, including higher-than-expected energy demand, adverse weather causing damage to pylons, a heatwave and claims that the government had failed to invest sufficiently in renewable energy.

Tesla's battery farm stores energy created from renewable sources like solar panels and wind farm, then feeds it into the national grid when demand is high. The battery is to cost the taxpayer AU$50m and will bring much-needed stability to the grid.

At 100 megawatts in size, the battery can store enough electricity to power 30,000 homes for just over one hour, local media reports. Made up of Tesla Powerpacks, the enormous battery is installed at Hornsdale windfarm, north of Adelaide, and is run by energy company Neoen.

Jay Weatherill, the premier of South Australia, said in a press release: "While others are just talking, we are delivering our energy plan, making South Australia more self-sufficient, and providing backup power and more affordable energy for South Australians this summer."

Beating his own deadline is something of a surprise from Musk, who is famous for delaying products. The Tesla Model S and Model X both endured setbacks before going on sale, and the Model 3 is currently suffering from manufacturing bottlenecks as the electric car company works through a half-million name order book for its cheapest car yet.