“Much-needed” four-hour big battery moves to construction phase, the first with a CIS contract

Construction of the 100MW/400MWh Merredin battery energy storage system (BESS) will soon get underway in the south west of Western Australia, after the Atmos Renewables project reached financial close this week.

Atmos announced the “significant milestone” for the big battery on Wednesday, marking the company’s first greenfield development to enter construction phase – and likely the first project to reach construction in WA under the federal government’s Capacity Investment Scheme.

The 100MW, four-hour BESS is being developed around 7.5km south-west of the town of Merredin, which is approximately 230 km east of Perth in the West Australian Wheatbelt.

Atmos says the battery, which secured state development approval in April 2024, is strategically positioned midway along the 650 km Muja to Kalgoorlie 220 kV transmission line, supporting WA grid stability and energy security for the Wheatbelt and Eastern Goldfields regions.

Construction will be led by GenusPlus Group and the project will use Tesla Megapacks with grid-forming inverter technology. Western Power will manage the high-voltage connection works to the Merredin Terminal Station.

“The Merredin BESS exemplifies our commitment to delivering reliable, clean energy solutions tailored to the needs of Western Australians,” said Atmos CEO Nigel Baker in a statement on Wednesday.

“Western Australia, we’re here,” the company added on LinkedIn. “The Merredin Battery Energy Storage System (BESS) has reached financial close and we’re proud to announce that we’re building for long-term impact.

“This project will be Atmos’ first in WA, our first standalone battery and the first time we’ve taken a greenfield development all the way from the drawing board to delivery,” the LinkedIn post says.

“But the real story is what comes next: More flexible, reliable energy; jobs and investment for local businesses; long-term partnerships with First Nations communities, [and] a voluntary Community Benefit Fund backing health, education and environment.”

Josef Tadich, the head of Tesla Energy in the APAC region, has also welcomed news of the project’s progress.

“This adds another much-needed battery energy storage system to the WEM [Western Electricity Market], charging from the world-beating solar resource, and providing fast and flexible generation to support the close to 2GW ramp needed to meet the early evening peak,” Tadich wrote on LinkedIn on Wednesday.

“Another great project in WA, and we’re excited to be part of it!”

As noted above, the Merredin BESS is one of four big battery projects that won the first storage tender in WA under the federal government’s Capacity Investment Scheme.

The winners, announced in March, also included the the 324 MW, 1,200 Boddington Giga Battery, which will be paired with a solar farm, and has been proposed by PGS Energy, Neon’s 150 MW, 615 MWh Mulchea battery, and Frontier Energy’s Waroona project (80 MW, 380 MWh).