British clean energy investor, Octopus Australia, has struck a deal with Enervest to acquire Hanworth battery energy storage system (BESS) in New South Wales (NSW), paving the way for a combined $3.3 billion investment across two major battery projects in Australia.

The 1.2 gigawatt (GW) / 4.8 gigawatt-hour (GWh) battery located near Bannaby in the NSW Southern Tablelands, the Hanworth Battery is set to become Australia’s largest battery project, more than double the size of the Waratah Super Battery north of Sydney. Once operational, the battery will strengthen grid stability across surrounding regions.

The transaction reflects Enervest’s strategy to develop and de-risk large-scale energy assets before transitioning them to long-term owners, while sharpening its focus on an own-and-operate portfolio. Enervest will continue to support Octopus Australia through the planning process and remain actively involved as a long-term landholder and regional stakeholder.

Costing more than $2 billion, the Hanworth BESS is expected to supply enough stored renewable electricity to power more than half a million homes during evening peak demand, soaking up surplus solar and wind generation produced during the day.

Octopus Australia is also acquiring the Dunmore battery project in Queensland from Samsung C&T Renewable Energy. Dunmore will combine a 300-megawatt solar farm with a 150-megawatt battery offering two hours of storage, representing a further investment of around $1 billion.

Together, the projects form part of Octopus’ broader strategy to bundle wind, solar and storage assets to deliver firmed, around-the-clock clean electricity capable of competing with traditional baseload coal and gas generation.

Sam Reynolds, Chief Executive at Octopus Australia, shared that battery storage is essential to unlocking the full value of renewable energy, pointing to strong backing from Australian and international institutional investors as key to the company’s long-term strategy.

“If you don’t have storage to firm weather-dependent renewables, it’s difficult to compete with coal and gas,” Reynolds said.

The projects come as NSW accelerates its rollout of large-scale storage to support the transition away from coal. The state recently announced six major battery projects under its latest long-duration storage tender, marking the largest battery rollout in NSW’s history.

Financial close for both the Hanworth and Dunmore projects is targeted for June 2028, with both expected to play a significant role in Australia’s evolving energy system through the 2030s.