The world’s biggest lithium-ion battery is about to get even bigger after its Australian operators decided to expand in a bid to stabilise the nation’s fragile electricity grid. French renewables company Neoen said on Tuesday that it had contracted Tesla to expand capacity at its Hornsdale Power Reserve in South Australia by 50 per cent to 150 megawatts.

The Australian government has pledged up to A$72m in grants and loans to support the expansion, which comes as rival projects in the US and elsewhere threaten to steal the crown as the world’s largest lithium-ion storage facility.

The South Australian battery, which was built in 2017 in just 100 days following an audacious bet by Tesla’s founder Elon Musk that he could fix the state’s energy crisis, is connected to a wind farm and has the capacity to supply about 30,000 homes for one hour. Neoen said the battery saved consumers A$5om in its first year of operation and that those savings would grow when the expansion is completed in 2020.

It said the facility would become the first large-scale battery in Australia to provide inertia and fast frequency services – important elements needed to maintain grid stability –   to the national electricity network. “The expansion of Hornsdale Power Reserve is demonstrating the critical and multiple roles that batteries will play in the grid of the future,” said Louis de Sambucy, managing director of Neoen Australia.

Australia is undergoing a boom in renewable energy, which accounts for more than a fifth of electricity generation. Over the past two years the country has deployed wind and solar generation up to five times faster than the US, China or the EU on a per capita basis, according to a report by Australian National University. But the rapid expansion has come at a price. Australia’s Energy Market Operator warned last year that theurge of renewable energy projects could destabilize the grid – an issue that took center stage after a statewide blackout in South Australia in 2016 following a storm.