Huge Liddell battery hits full commercial operations, completing state’s “firming” line-up ahead of El Niño summer

The huge, two-hour battery built at the site of its now partly demolished Liddell coal plant in the New South Wales Hunter region has reached full commercial operation, marking a major new milestone for the grid and delivery of all four projects selected for support in the state’s second tender for firming capacity.

AGL Energy said on Friday that its 500 megawatt (MW), 1000 megawatt-hour (MWh) – or one gigawatt-hour – Liddell Battery was now “fully operational,” taking the utility’s plans for the coal-free Hunter Energy Hub a step closer to being realised.

The first 250 MW and 500 MWh stage of the Liddell battery energy storage system (BESS) was commissioned in March, followed by partial commercial operations starting in June.

AGL says the project received official technical sign-off from the Australian Energy Market Operator (AEMO) and the local Transmission Network Service Provider (TNSP), Transgrid, at the end of July. Final reliability testing was completed this Tuesday, marking practical completion of the project.

“This is the first major development at the former thermal power station site and an important step in our plans to transform Liddell,” AGL said in a LinkedIn post on Friday.

“As one of the largest batteries in the National Electricity Market, it will help keep the grid reliable as more renewable energy comes online and support our customers through the energy transition.”

The milestone at Liddell means all four of the winners of the second round of the NSW Electricity Infrastructure Roadmap have now been delivered – an “important milestone” on its own that was also marked on Friday by state energy minister Penny Sharpe.

The four projects include three big batteries – two of them of gigawatt-scale proportions – and a virtual power plant (VPP).

Alongside the Liddell BESS is Akaysha Energy’s Orana BESS, which at 415 MW and 1,660 MWh this year became one of the largest four-hour battery projects to be added to Australia’s main grid and in June commenced full commercial operations, just weeks after reaching full output.

The third battery project delivered through the second NSW firming tender is Iberdrola Australia’s Smithfield BESS, a 65 MW and two-hour (130 MWh) facility that is co-located with an existing peaking gas plant in Greater Western Sydney.

The VPP, delivered by Enel X, has a combined capacity of 95 MW and a minimum dispatch duration of two hours, which has already been called upon to provide flexible demand to the state’s grid during last summer’s 2025 heat event and through periods of peak demand.

Sharpe says the Tender Round 2 was delivered under the NSW Roadmap, with additional support from federal Labor, to bring forward private investment in the firming the state needs to maintain reliability as coal-fired power stations retire.

The minister says the projects have also delivered economic benefits to their surrounding communities, supporting more than 1,500 jobs during construction.

“The completion of these batteries and the virtual power plant is an important milestone for NSW,” Sharpe said in a statement on Friday.

“Together, these projects can provide enough firming capacity to meet the peak electricity demand of around 400,000 homes, helping keep the lights on during the hot summer to come.”

Akaysha Energy CEO Nick Carter says the completion of the projects demonstrates how government policy and private investment can work together to accelerate the energy transition and maintain electricity reliability.

“As the developer and operator of the Orana BESS, one of the largest batteries in NSW, we’re proud to have delivered this on time and help support NSW’s energy security for years to come and provide critical capacity when the grid needs it most,” Carter said on Friday.

So far, seven tenders for Long-Term Energy Service Agreements (LTESAs) and renewable energy zone (REZ) Access Rights been completed under the NSW Electricity Infrastructure Roadmap.

The most recent – a bonus firming round announced in February to plug any supply gaps left by the state’s retiring coal plants and cater to other possible risks – awarded contracts to AGL’s giant 500 MW and four-hour Tomago battery and, again, to Enel X, for another 32 MW of VPP capacity.

Alongside the NSW Long Term Energy Service Agreement (LTESA), the Liddell BESS was supported by a grant from Arena, while extra state government support was extended to Transgrid and the Australian Energy Market Operator (AEMO) to fund more engineers to fast track the project.

“The start of full commercial operations confirms the battery is now delivering grid-scale energy storage services at its intended operating capacity, providing fast-response support to the electricity network and helping manage volumes of renewable energy into the system,” Transgrid executive general manager of network Jason Krstanoski said on Friday.

“The successful transition of the Liddell BESS to full commercial operation will strengthen our state’s energy security and reflects the successful delivery of the project under the … LTESA program.”

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