Eku Energy Commissions 250-MW Big Canberra Battery at Williamsdale

• Eku Energy commissioned the 250-MW / 500-MWh Williamsdale battery in Canberra on Nov. 5, the largest part of the Big Canberra Battery program.
• Its 136 Tesla Megapacks can cover one-third of Canberra's electricity needs for up to two hours at peak demand, the ACT Government said.
• Under a revenue swap, the Territory takes a share of the battery's market earnings and pays Eku fixed quarterly sums for 15 years.

Eku Energy has commissioned the 250-MW / 500-MWh Williamsdale battery in southern Canberra, the company said on Nov. 5. It is the largest part of the Australian Capital Territory's Big Canberra Battery program.

The plant can meet one-third of Canberra's electricity needs for up to two hours at peak demand, the ACT Government said in a joint statement. It runs on Tesla Megapack 2 XL batteries. Consolidated Power Projects was Eku's balance-of-plant contractor, and Evoenergy is the distribution network service provider. AEMO supported the grid connection approval.

The Territory chose Eku in April 2023 and put the cost at A$300 million to A$400 million ($210 million to $280 million). Under a revenue swap, the ACT receives a share of the battery's earnings in the National Electricity Market. In return, it pays Eku fixed quarterly amounts for 15 years. Westpac, SMBC and MUFG Bank financed the project, and Habitat Energy optimises its market trading.

The battery in numbers

• 136 Tesla Megapack units sit in 12 collector grids, each with 12 step-up transformers, according to the ACT Government.
• 2 hours of output at the full 250 MW, and about 3.7 MWh of storage per Megapack (list.solar calculation).
• 180-plus tonnes is the weight of the main transformer that connects the batteries to the network.
• 150 jobs at peak construction and A$1 million ($700,000) in community benefits funding, the government said.
• About 2% is Williamsdale's share of NEM grid-scale battery capacity, which topped 23 GWh at the end of September, AEMO data show (list.solar calculation).
• 8.0% of NEM evening-peak supply came from grid-scale batteries in the third quarter, above gas for the first time, AEMO said.

AEMO lists Williamsdale in its New South Wales market region, as one of four NEM batteries that began commissioning in the third quarter. The nine big batteries Australia commissioned in the first half of 2026 averaged 792 MWh, Clean Energy Council figures show. Construction at Williamsdale started in November 2024.

The battery "is now ready to provide energy security and support the ACT's electricity needs for the long term," Chief Operating Officer Tom Best said.

The wider battery storage program also covers behind-the-meter units at nine government sites and neighbourhood batteries in Dickson, Casey and Fadden. Eku will continue to manage Williamsdale. The battery will provide energy and system security services, particularly in summer, when the grid can come under stress, the company said.