The largest battery energy storage system in Canberra's history is now operational, with the ACT government saying the batteries could power one-third of the city's electricity needs for two hours during peak demand.
The Williamsdale site, south of Tuggeranong, houses 136 Tesla Megapack 2 batteries connected to the electricity grid. The system absorbs excess energy when demand is low and releases it when demand is high, a process described by Eku Energy policy director Rachel Rundle. "Essentially they're plugged into the electricity network. They are always on … because they're always on, they soak up all of the excess energy that is in the network," she said. "Lots of that excess energy comes from the great wind and solar resources that we have in Australia." Rundle said the battery could quickly store up to 500 megawatt-hours and discharge that amount each day.
The project's timeline blew out twice after completion was projected for 2025 and later extended to early 2026, which was also not realised.
Under the operating agreement, Chief Minister Andrew Barr said the government would pay Eku Energy a support charge of $368 million in instalments across 15 years and is entitled to 50 per cent of the battery's net revenue. Barr said he expected the project to be revenue-positive. "So, the territory makes a contribution, then receives more in its share of the revenue," he said. He said the technology was being built for households, small businesses, hospitals, schools, universities and Canberra's industrial output, including data centres.
Eku Energy chief operating officer Tom Best said there were no guarantees the system would put downward pressure on Canberra household electricity bills. "It's an open market, so we can't influence the market outcomes, but by bidding the capacity during those periods of high demand, we may have an impact on pricing, but it's not something we can guarantee," he said.
Analysis
Why This Matters
- The battery helps integrate renewable energy into Canberra's grid, reducing strain during peak demand and potentially improving reliability.
- It represents a substantial public-private investment in energy storage, with a financial model that aims to be cost-positive for the government.
- The project could serve as a benchmark for similar storage initiatives across Australia.
Background
The Williamsdale battery is the largest energy storage facility in Canberra's history, using 136 Tesla Megapack 2 units. Originally slated for completion in 2025, the timeline slipped first to early 2026 and finally to later that year, when it became operational. The project is part of the ACT's broader push to boost renewable energy capacity and grid stability.
What to Watch
- Whether the battery's revenue meets expectations and the government's share turns the project cost-positive.
- The actual effect on household electricity prices in Canberra, given the company's caveat that it cannot guarantee downward pressure.
- The potential for the Williamsdale model to be replicated in other Australian states and territories.
Checked
12 claims in this story checked against 1 source: 12 supported.
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- SupportedCanberra's largest battery system is online.Latest business news: “The largest battery energy storage system in Canberra's history is online”
- SupportedThe batteries could power one-third of Canberra's electricity needs for two hours at peak demand.Latest business news: “the batteries could power one-third of Canberra's electricity needs for two hours in times of peak demand.”
- SupportedThe government and Eku Energy partnered on a 250-megawatt battery project.Latest business news: “The project is a partnership between the government and private company Eku Energy, which designed, built and owns the 250-megawatt capacity batteries.”
- SupportedThe government will pay Eku Energy a $368 million support charge in instalments over 15 years.Latest business news: “the government would pay Eku Energy a support charge of $368 million in instalments across 15 years.”
- SupportedThe project's completion timeline was extended from 2025 to early 2026, but that later date was not met.Latest business news: “its delivery was projected to be in 2025, then later extended to early in 2026, which was also not realised.”
- SupportedRundle said the batteries are connected to the network and absorb excess energy when always on.Latest business news: “"Essentially they're plugged into the electricity network," she said. "They are always on … [and] because they're always on, they soak up all of the excess energy that is in the network.”
- SupportedRundle said much of the excess energy comes from Australia's wind and solar resources.Latest business news: “"Lots of that excess energy comes from the great wind and solar resources that we have in Australia.”
- SupportedRundle said the battery could store up to 500 megawatt-hours and discharge that amount each day.Latest business news: “Ms Rundle said it could quickly store up to 500-megawatt hours and then discharge that amount each day.”
- SupportedThe government is entitled to 50 per cent of the battery's net revenue.Latest business news: “The government is entitled to 50 per cent of the battery's net revenue, which it earns when energy is sold back to the grid.”
- SupportedBarr expected the project to become revenue-positive.Latest business news: “Mr Barr said he expected the project to become revenue-positive.”
- SupportedBarr said the territory contributes money and then receives more through its share of revenue.Latest business news: “"So, the territory makes a contribution, then receives more in its share of the revenue," he said.”
- SupportedBest said the system might affect prices during high demand, but there is no guarantee it will lower household electricity bills.Latest business news: “"It's an open market, so we can't influence the market outcomes, but by bidding the capacity during those periods of high demand, we may have an impact on pricing, but it's not something we can guarantee," Mr Best said.”