A joint venture of Siemens and AES wants to ease transmission for wind and solar in Australia with two huge batteries that would dwarf the world-record storage facility built there by Tesla in 2017.

Fluence, a 50/50 JV between the German industrial giant and US power group, is proposing twin 250MW/125MWh lithium-ion batteries in Victoria and New South Wales to act as a ‘virtual transmission line’ between the two key renewable states.

Fluence could build the facilities in less than 14 months, it says in a submission to the Australian Energy Market Operator (AEMO).

The batteries would eclipse the 100MW/129MWh Hornsdale battery, currently adding a 50MW/65MWh expansion, installed by Tesla to much fanfare in 2017 after the US group’s CEO Elon Musk famously took up a personal challenge by Twitter. The battery linked to Neoen's Hornsdale wind farm remains the world's largest, although is soon set to be outstripped by other giant projects globally.

Australia is home to massive renewable energy development but facing major network challenges, with grid congestion threatening to choke a 67GW project pipeline unless solutions are found, research group WoodMackenzie said earlier this year.

Fluence told Bloomberg, which first reported the submission, that the batteries’ effect on the network would be similar to “widening a highway instantaneously to accommodate surges in traffic”, for example from wind and solar, removing the need for costly extra transmission infrastructure.

Other major storage plans mooted in Australia and reported by Recharge include a 900MW storage facility proposed by Neoen.