AEMO found the battery had been highly profitable for its operator, French energy company Neoen, as it was able to charge up when energy prices were low and release energy to the grid when prices were high.

The price of the 8.9 gigawatt hours the battery had discharged into the grid during the quarter, mostly in the late afternoon peak, was $90.56 per megawatt hour higher than the 11 gigawatt hours it had used to charge up during the quarter.

Mr Cannon-Brookes said the battery had "far surpassed everybody's expectations", and that those who had dismissed its relevance had been proven wrong.

Given its 100 megawatt output in a South Australian energy market whose peak demand is about 3000 megawatts, Treasurer Scott Morrison had compared the battery's usefulness to Coffs Harbour's Big Banana, while Resources Minister Matt Canavan had dismissed it as "the Kim Kardashian of energy".

Tech billionaire Mike Cannon-Brookes says his brokering of Tesla's big battery has been vindicated. Daniel Munoz

However Mr Cannon-Brookes said only somebody "in the gas cartel" would dispute a bigger role for battery storage in the energy market.

"First they mock you, then they fight you, then you win," he had tweeted upon the release of the McKinsey & Co report earlier this month.

"Let me be clear: the SA government invested $50 million, consumers/taxpayers saved $35 million in the first four months. At that rate, $105 million in year one of a 20 years-plus infrastructure asset. Wave a lump of coal at that!"


He acknowledged to The Australian Financial Review that batteries were not a "magical solution" for all of Australia's energy problems, and that the second large battery in any given market would today be far less profitable than the first, given how the FCAS market operates.

Asked whether the early performance of Tesla's battery had forced a government rethink on the technology, a spokesperson for Energy Minister Josh Frydenberg said there was nothing to reconsider.

"We support battery projects and have put millions into them," he said, pointing to the Australian Renewable Energy Agency's investment of $25 million in Victoria's first two large-scale grid-connected batteries, linked to wind and solar farms, as an example.

Mr Frydenberg singled out batteries in his National Press Club address last month, stating that energy storage was critical "because the stability of our grid cannot be left to the whim of the weather".

Mr Cannon-Brookes revealed he had become a major investor in solar farms via his Grok Ventures investment company.