The world’s largest lithium ion battery is up and running in South Australia where officials hope it will help reduce power shortages during blistering summer weather that lies ahead.

The state government announced last week that the football-field-sized battery has been installed at the Hornsdale Power Reserve, where it will store energy generated at an adjacent wind farm. According to a statement from South Australia Premier Jay Weatherill, the battery is “history in the making” and will ensure that the state has backup power to get it through the summer.

Tesla finished installing the 100-megawatt battery only 63 days after signing an agreement with state officials, well under the 100 days CEO Elon Musk promised — a deadline he vowed to meet or do the job for free.

It makes great press for Tesla. In South Australia, officials hope that the battery will reduce the number of blackouts and brownouts that typically occur. Although more than 40% of South Australia’s electricity comes from wind, integrating the energy into the grid and managing the intermittent nature of wind-generated power hasn’t been very successful, according to an expert quoted in an article published by The New York Times.

South Australians pay the highest electricity prices in the world, the article said, and electricity costs there have gone up 20% between 2012 and 2016. Residents pay between 50% and 100% more for electricity than Americans.

The battery has enough capacity to power 30,000 homes for as much as an hour — not a huge number when compared to South Australia’s population, but enough, officials hope, to reduce pressure on the grid during periods of high demand.

Federal policy favors coal

Australia has plenty of wind and solar capabilities, but the federal government has been promoting fossil fuels over renewable energy, and Australia’s treasurer, Scott Morrison, was disdainful of the Tesla project earlier in the year. “Thirty thousand South Australian households could not get through watching one episode of ‘Australia’s Ninja Warrior’ with the big battery,” he said.

The government of Prime Minister Malcolm Turnbull has promoted fossil fuels to stimulate growth and prevent power shortages in South Australia, The Times said, and suggested the state had been taken in by clever salesmanship with the Tesla project.

In an email to the newspaper, energy minister Josh Frydenbert said, “The Tesla battery has been sold to the people of South Australia as an answer to their woes. But in reality it is just a fraction of the storage and backup that South Australia needs.”

Not so, said the Australian general manager of Neoen, the French company that owns the nearby wind farm. “There’s no turning back,” said Franck Woitiez. “It’s not tomorrow, it’s now.”