December 19, 2025: Origin Energy has announced it will further expand planned capacity of its Eraring super BESS in Australia by 360MWh to an overall total of 700MW/3,160MWh, providing 4.5 hours of storage on average.

Origin said on December 11 it has committed A$80 million ($53 million) for the fourth stage development of the New South Wales BESS, with construction starting by the end of this year and the additional capacity coming online in the first quarter of calendar 2027.

Battery equipment for stage four will be supplied by Finnish technology group Wärtsilä and design and construction services will be provided by Enerven, consistent with the rest of the project. 

Head of energy supply and operations, Greg Jarvis, said the investment strengthens the site’s status as the largest approved BESS in the southern hemisphere.

“As Australia continues its energy transition, large-scale batteries will be essential for reliable supply of energy, supporting more renewables coming online and helping ease pressure on wholesale prices.”

Work on the first stage (460MW) of Eraring began in April 2023 and was set to start commercial operation before the end of 2025.

Stage two (240MW) development was launched in July 2024 and is set to start commercial operation in the first quarter of 2027.

Meanwhile, work on the third stage (adding 700MWh to the stage one battery) started in 2024 and is set for commercial operation by the end of 2025.

Origin has committed to developing or contracting 1.7GW in owned and tolled large-scale battery projects across the country, including at Eraring, Mortlake Power Station in Victoria, the Summerfield battery storage project in South Australia and the Supernode battery in Queensland.