Williamsdale Battery Energy Storage System

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250MW / 500MWh


Eku Energy has partnered with the Australian Capital Territory (ACT) Government to deliver a 250 megawatt (MW) / 500 megawatt-hour (MWh) battery energy storage system (BESS).  

Located at Williamsdale in the south of Canberra, the battery will store enough renewable energy to power one-third of Canberra for two hours1 during peak demand periods, increasing energy security and reliability for Canberrans. 

The Williamsdale BESS is part of the ACT Government’s Big Canberra Battery project. It further supports Canberra households in their use of renewable energy and the ACT Government’s commitment to achieving net zero emissions by 2045.  

The Williamsdale BESS will provide a range of energy and essential system security services, particularly during the summer season when the electricity grid can come under stress. It can also provide fast acting frequency control services in just a few milliseconds to support the grid and minimise risks of disturbances.

1Based on ACT 2022 Winter Maximum Demand of 680MW


  • 2023: Project announcement
  • 2024: Development phase
  • 2025: Construction phase
  • 2026: Operations

Project Updates

View the Development Application for Williamsdale Battery Energy Storage System.



Acknowledgement of Country

Eku Energy respectfully acknowledge the Ngunnawal and Ngambri People, the traditional custodians of the land on which the Williamsdale BESS will store energy. We pay our respects to elders, past and present. We acknowledge and respect their culture, beliefs, contributions, and spiritual and historic connection with the land.


Eku Energy is proud to deliver the Williamsdale BESS in the Australian Capital Territory with the support of our valuable partners.


What is the Williamsdale BESS? 

The Williamsdale BESS is a 250MW / 500MWh grid connected BESS that will have capacity to store enough renewable energy to power one-third of Canberra for two hours during peak demand periods. It will be located close to the Williamsdale substation. The Williamsdale BESS is a significant step towards the Territory’s strategy to build a battery ecosystem. The Williamsdale BESS will support a reliable and affordable electricity supply in the ACT as it transitions to net-zero emissions.

Who is delivering the project? 

Eku Energy is responsible for the development, construction, operation and active management of the Williamsdale BESS. It will share 50% of the net revenue with the Territory under an innovative revenue share agreement, supporting the Territory to deliver safe, secure and reliable energy.  

What are the timeframes? 

The project is expected to reach financial close in 2024 and commence operations in early 2026. 

Why is the Williamsdale BESS being developed? 

Energy storage is a key priority for the ACT Government as it transitions away from fossil fuels and gas and pursues its plan to reach net zero emissions by 2045. 

This grid-scale storage system can store as much electricity as can be generated from 25,000 average solar rooftop solar systems on an average day2. Batteries can store excess renewable energy to be used at later times of higher demand - thereby extending the benefit of renewable energy into the evenings. It will increase the renewable energy hosting capacity across the ACT enabling more Canberrans to access the benefits of renewables.

What role will the Williamsdale BESS play in the National Electricity Market? 

The Williamsdale BESS will be registered to participate in the National Electricity Market (NEM), the main interconnected electricity network which covers the entire east coast of Australia. The BESS will participate in the energy market, charging during times when there is excess renewable energy and low prices, and discharging that energy at times when demand on the grid is higher. 

The Williamsdale BESS will also participate in a range of other markets for ‘essential system services’ – for example, markets for frequency control services. These services help keep the grid operating in a safe and secure envelope. 

How long can the battery provide power for? 

The battery can provide 250MW of dispatchable power over two hours. 

Is the Williamsdale BESS designed to only store renewable energy? What other sources of energy will it store? 

The Williamsdale BESS is a grid-connected asset and it will charge from the grid that uses a range of generation sources from across the NEM - this includes both renewable and non-renewable energy. However, with more renewable energy coming into the grid, the Williamsdale BESS will enable more renewable energy to be stored as we reduce Australia’s reliance on fossil fuel generated electricity in the NEM. 

When will it be constructed? 

Construction will commence in late-2024 and is expected to be completed early 2026. 

How many jobs will be created through the project? 

During the peak of the construction, we estimate approximately 180-200 jobs will support the project. 

Why was Williamsdale chosen as the location for the BESS? 

The 250MW / 500MWh Williamsdale BESS will be located within the Territory, close to the Williamsdale substation. It will have a direct connection to EvoEnergy’s 132kV electricity network and will be connected to the local ACT grid to help provide safe, secure and reliable power to over 450,000 Canberrans. 

Who else benefits from the Williamsdale BESS? 

The Territory sits within the largest region in the NEM in New South Wales. Considering the projected timeframe for commencement of operations, the Williamsdale BESS will be an important asset in supporting the energy transition with the retirement of coal-fired power stations such as Liddell and Eraring. Utility-scale batteries are critical in supporting the safe, secure and reliable operation of the NEM and it provides important firming and system security services to the system and energy users.

2Based on an average installed rooftop solar PV system size of 5kW, generating on average 20kWh/day.

Request more info

If you would like to contact a member of our team directly to ask a question or discuss matters about this project, please contact us below:

Email:    williamsdale@ekuenergy.com

Call:       (+61) 1800 989 687   (Toll free within Australia)