Construction begins on new four-hour big battery in W.A.

Construction has begun on the new 100-megawatt (MW) four hour Merredin Big Battery in the southwest of Western Australia, with the project expected to be completed in October, 2026.

The Merredin Big Battery is being developed between Atmos Renewables and Nomad Energy, who took a final investment decision last month and quickly moved to appoint local construction firm GenusPlus Group to design and construct the project.

Located approximately 8 kilometres southwest of Merredin in Western Australia’s Wheatbelt region, the 100 MW/400 MWh battery will help to strengthen and stabilise the state’s main power grid.

The battery is also being strategically posited alongside the 650-kilometre Muja to Kalgoorlie 220-kilovolt transmission line where it will help support energy security for the Wheatbelt and Eastern Goldfields regions and improve the line’s stability and capacity as the state continues its transition to clean energy.

The battery’s construction adds to recent renewable energy projects in the region, including the 222 MW Collgar wind farm and the 132 MW Merredin solar farm.

Once operational, the Merredin Big Battery will join nearly 500 MW worth of mostly four hour battery storage that has begun operationg in the South West Interconnected System (SWIS) since 2023, and precede a further 728 MW of committed storage that is expected to be brought online in the next 18 months.

These include two of the country’s biggest batteries, Neoen’s 560 MW and 2240 MWh facility and Synergy’s 500 MW and 2,000 MWh facility – both being built and commissioned in Collie.

“Grid-scale batteries play an important role in our clean energy transition, storing excess energy during the day and discharging it at night – helping to stabilise and strengthen our electricity grid,” said Amber-Jade Sanderson, state minister for energy and decarbonisation.

“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.

“Together with new transmission lines, wind, solar, and gas generation where needed, they are important elements of the energy grid of the future.”

Construction of the Merredin Big Battery is expected to create up to 70 jobs during the peak of construction, and five permanent jobs during the battery’s operational lifespan.

“The Merredin Big Battery will create jobs, benefit First Nations employees and contractors, and contribute to local education initiatives,” added Sanderson.

“The developers and the community have established a community benefit fund that will financially support local community initiatives throughout the life of the project.”