Australia: "A major piece of future proofing:" Canberra's biggest battery powers up to underpin net zero, electrification

The ACT has officially “flicked the switch” on its biggest battery, kicking off operations at the centrepiece of the territory government’s Big Canberra Battery project, designed to deliver energy security for Australia’s Capital, underpin electrification, and help get it to net zero emissions by 2045.

The 250 megawatt (MW) and 500 megawatt-hour (MWh) Williamsdale Battery Energy Storage System (BESS), located in Tuggeranong, was developed by Eku Energy, the global battery storage platform of investment giant Macquarie.

The facility includes 136 Tesla Megapack 2 XL batteries arranged in 12 collector grids, each with 12 step-up transformers. The batteries are connected to the electricity network through a main transformer that is “larger than an Action bus” and weighs over 180 tonnes.

At an official celebration held on Thursday and attended by ACT chief minister Andrew Barr, Eku Energy pronounced the project fully commissioned and operating commercially – delivered “on time and on budget” with the capacity to power one-third of Canberra through two hours of peak demand.

“As more Canberrans switch to electric vehicles and electric appliances in their homes and businesses, we need to make sure our energy system is ready to meet that growing demand,” said Barr.

“The Big Canberra Battery is a major piece of that future-proofing. It will help keep our energy network reliable and resilient, make better use of renewable energy, and support Canberra as we continue to electrify our city.

“This is an investment in Canberra’s future that will benefit our community for decades to come, improving energy security while supporting our transition to net zero emissions by 2045.”

Eku Energy COO Tom Best described the battery’s completion as “a huge achievement,” and thanked the project delivery partners, including contractor Consolidated Power Projects, Evoenergy as the electricity distribution network service provider and AEMO supporting the grid connection approval process.

“We’re delighted to have commissioned the Williamsdale BESS, which is now ready to provide energy security and support the ACT’s electricity needs for the long term,” said Best.

For Eku, this is the third big battery the company has delivered in Australia, alongside the 150 MW/150 MWh Hazelwood BESS and the 200 MW/ 400 MWh Rangebank BESS, both now in operation in Victoria.

But Eku Energy’s head of policy, Rachel Rundle, says the Williamsdale project has been significant for the company for a number of reasons, including that it is the first battery it has developed with 100% equity ownership.

“[The ACT is] really leading the way across all states and territories in the NEM in … transitioning their electricity system and their energy system at large. And part of that was the big Canberra battery program that they initiated themselves,” Rundle told Renew Economy in an interview.

“We had a very clear vision of of what we wanted and needed to deliver for the territory. … [From] working with them to deliver this project way back in 2023, to then starting construction in November 2024 …and now we’re up and operating in October 2026.”

Rundle says that now it’s up and running, the Williamsdale BESS will kick off its 15-year revenue share agreement with the ACT government, which helped to underwrite this battery’s construction and, once operational, will share 50 per cent of its revenue back with the territory government.

“So that then goes back into their revenues to help… continue their decarbonisation and broader agenda here in the territory,” she says.

The BESS is also helping to fund two local rooftop solar and battery storage systems for local not-for-profit organisations, as part of a combined $500,000 community benefit program.

In total Eku Energy is supporting nine community groups through its Powering Big Dreams program , established alongside the novel revenue sharing deal the company negotiated with the ACT government in late 2024.

A separate $500,000 funding partnership with the Australian National University will help the ANU’s Centre for Energy Systems to examine the role of utility-scale batteries and improve public understanding of their benefits and challenges.