Fluence has signed its largest battery energy storage system (BESS) deal globally, partnering with Australian energy major AGL Energy to deliver a 500MW/2,000MWh grid-forming BESS in New South Wales. The Tomago BESS project represents a significant milestone for both companies and marks Fluence's largest project transaction worldwide.  

Project Details and Timeline

The 2,000MWh, 4-hour duration Tomago BESS will be located within the Tomago Industrial Estate, northwest of Newcastle, New South Wales' second-largest city. AGL received clearance for the project from the New South Wales government in November 2024.

Construction work for the BESS is expected to begin in late 2025, with the commencement of operations targeted for late 2027.  The battery storage system's expected asset life is 20 years and will connect to the National Electricity Market (NEM). With the signing of this deal, AGL confirmed it had reached a final investment decision (FID) on the grid-forming BESS.

Financial Investment and Funding

The total construction cost of this grid-forming battery storage project is estimated to be approximately AU$800 million (US$516 million). AGL revealed that the BESS would be funded on AGL's balance sheet, utilizing operating cash flows and existing debt facilities, including green capex loans.

For Fluence, this deal sees the company surpass the 5GWh threshold for Australian projects in its pipeline, highlighting the company's growing presence in the Australian energy storage market.

Technology and Implementation

Fluence will supply its Gridstack Pro for the utility-scale energy storage project. The company launched the Gridstack series in 2020, claiming it to be a highly customizable yet mass production modular BESS solution.

Gridstack Pro followed in 2023, which Fluence said at the time was aimed at the largest and most complicated projects its customers are undertaking. Fluence has been contracted to construct the project and provide ongoing service and maintenance for the battery storage system.

Strategic Significance and Future Plans

Damien Nicks, AGL's managing director and CEO, said taking FID on the Tomago BESS represents a significant milestone for the business, and that AGL now has a "clear pathway" for FID on a further 900MW of grid-scale battery storage systems.

"Once operational, the Tomago Battery will expand on AGL's existing suite of grid-scale battery assets and contracted capacity from third parties and further enhance our flexible asset portfolio," Nicks said. "Importantly, both the 250MW Torrens Island and 50MW Broken Hill Batteries have delivered strong performance since they commenced operations, and the 500MW Liddell Battery remains on track to commence operations in early 2026."

Jan Teichmann, senior vice president and president, APAC, at Fluence, hailed the deal, stating that it reiterates Fluence's commitment to supporting AGL's rollout of energy storage capacity across Australia. "Australia remains one of the most important storage markets globally, experiencing significant growth as the country accelerates its transition to renewable energy sources," Teichmann added.  

Fluence and AGL have collaborated on several Australian BESS projects over the last few years, including the 50MW/50MWh Broken Hill and 500MW/1,000MWh Liddell BESS projects located in New South Wales. AGL also has a target to add 12GW of renewables and firming to its portfolio by 2035.