OX2 starts building solar and battery project next to old coal mine

Swedish renewables developer OX2 has begun building a 135 MW solar farm and a 100 MW battery energy storage system at the site of an old coal mine in the New South Wales Hunter Valley.

May 20, 2026 David Carroll

Image: Idemitsu Australia

OX2 announced it has reached financial close on the Muswellbrook Solar Farm and battery project in the New South Wales Hunter region and construction of the estimated $302 million (USD 215.4 million) project would commence “immediately” with completion expected in 2028.

The Muswellbrook solar and battery project, being developed by OX2 in partnership with the Australian arm of Japanese resources and energy company Idemitsu, combines a 135 MW solar farm with a 100 MW, two-hour capacity battery energy storage system.

Once operational, the project is expected to produce about 347 GWh of clean electricity annually, enough to power approximately 52,000 homes.

That output is already accounted for with the solar and battery facility among nine Australian renewables projects to be signed up to power purchase agreements last month as part of a 430 MW deal with global tech giant Amazon.

Being built on land adjacent to the Idemitsu-owned Muswellbrook coal mine, which ceased operations in 2022, the solar and battery project is part of broader plans to transition the site into a renewable energy precinct. Idemitsu is working with energy producer and retailer AGL to develop a 400 MW, eight-hour duration pumped hydro project at the site.

OX2 Chief Executive Matthias Taft said the Muswellbrook Solar Farm and battery project marks a major step in the site’s transition to providing clean, renewable energy and supporting Australia’s future energy mix.

“I’m proud of the work that has brought this project to life and of our contribution to strengthening the energy supply in NSW,” he said. “The investment highlights our long-term commitment to Australia and supports our growth as an independent power producer.”

The project is part of OX2’s growing Australia project portfolio that includes seven operational solar farms with a total combined capacity of more than 2.4 GW.

Its project development portfolio consists of more than 3 GW of solar, wind, and storage projects in Victoria, NSW, Queensland, South Australia, and Western Australia. This includes the 90 MW Summerville solar and storage project in NSW and the 190 MW Sunshine State solar and battery project in Queensland.

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