GenusPlus to Build Atmos’ 100-MW Merredin Big Battery for WA

• GenusPlus lands AUD 65 m job to deliver Atmos Renewables’ 100-MW/400-MWh Merredin big battery, boosting grid stability in Western Australia’s Wheatbelt.

GenusPlus Group Ltd has clinched an AUD-65-million contract to engineer and construct the 100-MW/400-MWh Merredin Battery Energy Storage System (BESS) for Atmos Renewables, strengthening Western Australia’s push to firm up its isolated grid with long-duration storage. The balance-of-plant deal also covers a new high-voltage substation and associated civil works, and will proceed once the project reaches financial close in the coming weeks.

The four-hour lithium-ion battery will sit on a four-hectare site about 7.5 km south-west of the Wheatbelt town of Merredin and roughly 230 km east of Perth. Designed to discharge at full tilt for four hours, the plant will be capable of shifting midday solar surpluses into the evening peak and providing fast-response grid services on the South West Interconnected System (SWIS).

Strategically, the facility plugs into Western Power’s nearby Merredin Terminal Station and is positioned next door to the 100-MW Merredin Solar Farm, creating one of Australia’s largest solar-plus-storage hubs outside the main transmission spine. Atmos is developing the project in partnership with London-based Nomad Energy, adding to a renewables portfolio that already tops 1.7 GW of operating wind and solar assets across the National Electricity Market.

Once Atmos issues the notice to proceed, GenusPlus will mobilise a 70-strong workforce and draw heavily on Western Australian suppliers. The company expects an 18-month build programme, targeting commercial operations in early 2027—timed to coincide with the retirement of the state’s last coal units and a forecast surge in long-duration storage requirements.

For Atmos, backed by Igneo Infrastructure Partners, Merredin marks its first utility-scale battery and a flagship asset in the drive to decarbonise WA’s mining-rich Wheatbelt. For GenusPlus, the win cements a foothold in Australia’s booming storage market following recent substation and network packages for Neoen’s Collie BESS and Synergy’s Kwinana expansion. Industry analysts note that WA now has more than 1.3 GW of four-hour batteries built, under construction or contracted—evidence of the state’s shift from diesel and coal to agile storage that can stabilise frequency and soak up record rooftop-solar output.

With emissions-intensive industries hunting for firm green power, the Merredin Big Battery is expected to play a pivotal role, storing enough energy each cycle to run about 90,000 average homes and freeing grid headroom for the next wave of wind and solar build-outs across Australia’s sun-soaked west.