Construction has officially started on the 100MW/400MWh 4-hour duration Merredin battery energy storage system (BESS) in Western Australia.
The Meredin Big Battery is being pursued via a partnership between Atmos Renewables and Nomad Energy. It is set to be built adjacent to the 132MW Merredin solar PV power plant being developed by Risen Energy.
The project developers achieved financial close on the BESS in early July 2025, and is Atmos Renewables’ first greenfield development to enter the construction phase.
The battery storage project, located approximately 7.5km southwest of Merredin, along the 650km Muja to Kalgoorlie 220kV transmission line, is expected to be commissioned in October 2026.
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It will be connected to the South West Interconnected System (SWIS), the main electricity grid for the southwest of the state, including the capital, Perth, and operate in the Wholesale Electricity Market (WEM), the primary market for generators and retailers in the state.
Construction company, GenusPlus Group, was awarded a contract to build the 400MWh Merredin BESS in June.
Renewable energy developer Nomad Energy first identified the potential for the Merredin BESS in 2022, with close proximity to key energy infrastructure in the state. Nomad partnered with Atmos Renewables to support the development of the BESS.
As reported by Energy-Storage.news earlier this year, the Merredin BESS was one of the projects successful in Western Australia’s first Capacity Investment Scheme (CIS) tender, which was announced in March.
Amber-Jade Sanderson, the Western Australia minister for energy and decarbonisation, hailed the project, stating that it will add to the state’s “energy armoury” and help stabilise Western Australia’s electricity grid.
“The Merredin Big Battery will add to our energy armoury, which includes state-owned batteries in Kwinana and Collie, and the Neoen battery also in Collie,” Sanderson said.
“Together with new transmission lines, wind, solar, and gas generation where needed, they are important elements of the energy grid of the future.”
It is worth noting that the Merredin BESS developers have established a voluntary community benefit fund to provide financial support for community-based initiatives, projects and events.
Once operational, AU$20,000 (US$12,950) a year will be available through the Merredin Battery Community Legacy Fund, continuing over the project’s estimated 25-year life.
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