From shuttered coal plant to gigascale battery: AGL commissions first stage of giant Liddell BESS

A massive new battery that has been built at the site of a massive shuttered coal plant in the New South Wales Hunter Region is on track to join the state’s grid by the middle of the year, with commissioning of the gigascale project now well underway.

The major milestone for the AGL Energy-owned 500 megawatt (MW), 1000 megawatt-hour (MWh) – or one gigawatt-hour – Liddell Battery, was announced on Friday morning by the federal and New South Wales Labor governments.

The first stage of the project – 250 MW and 500 MWh – has now been fully commissioned after beginning the process at the start of the year, using the company’s own in-house algorithms. Commissioning has now started on the second stage, and is expected to be complete by May.

Both governments have backed the project: federal Labor with a $35 million grant from the Australian Renewable Energy Agency and NSW with a Long Term Energy Service Agreement (LTESA) awarded in November 2023. The Minns government also funded more engineers to fast-track the battery’s delivery.

Once fully operational, AGL’s Liddell battery energy storage system (BESS) will be, probably very briefly, the second-largest in the state, and will help firm up the state’s grid as more coal exits the system and more renewable energy comes online. It will store enough energy to power around 200,000 homes for two hours.

“Liddell helped power New South Wales for generations. Now the same site is helping power the next chapter, with one of Australia’s largest batteries backing reliable renewable energy for decades to come,” said federal energy minister Chris Bowen on Friday.

“The Hunter has always been an energy powerhouse, and it will remain one. Our job is to make sure communities like this are at the centre of Australia’s energy transformation, with more investment, more reliable power and more local jobs.”

Liddell is the third NSW coal generation site to be transformed into a battery storage hub, alongside the 850 MW, 1680 megawatt-hour (MWh) Waratah Super Battery at the site of the shuttered Munmorah coal plant, and the 700 MW, 2,800 MWh Eraring battery being built next to the country’s biggest coal generator, also in NSW.

Both of those coal hub-based batteries will wind up being bigger than the Liddell BESS, but currently Akaysha Energy’s Waratah battery is currently operating at about half of its promised capacity, at 350MW (740 MWh), due to a transformer failure.

Its remaining capacity is now scheduled to come online by the end of 2026, nearly two years after its original schedule.

The commissioning of the Liddell BESS comes as the Australian Energy Regulator confirms that a flurry of new wind energy generation and battery storage has helped to put downward pressure on wholesale electricity prices in NSW and other NEM states.

“In April 2023 we closed Liddell Power Station after 50 years of operation with a celebration of the people of Liddell and the contribution that the power station made to the Hunter region and Australia’s energy system,” AGL CEO Damien Nicks said in a statement.

“Three years on I am proud to stand here today, to celebrate the commissioning of the Liddell Battery as the first major development in our plans to repurpose this site.”

AGL says it continues to progress the transformation of the Liddell site as part of its vision to create an integrated energy hub with a grid-scale battery, and potential partners in materials recovery and recycling, low carbon fuels and data centres all under consideration.

“When you think about the transition at Liddell from a long-standing old coal-fired power station to now one of the largest batteries in Australia, coal-fired power stations are aging and have become unreliable and expensive,” federal deputy climate minister Josh Wilson told ABC Radio in Newcastle on Friday morning.

“And in fact, they are causing a lot of the cost pressures that Australians have experienced. So, we need to make that transition.

“We’ve got far more solar energy than we can use. It’s incredibly cheap. It’s virtually free. When you have big batteries, you soak up that abundant energy and you redeploy it later in the day,” Wilson said.

“That is good for the health of the system. It’s certainly good for bringing down prices.

“And we’ve just seen yesterday, the latest indications about the what’s called the next Default Market Offer suggests that prices for households and businesses from the middle of the year will come down. Some suggestions here in NSW by around the 10% mark.

The Liddell milestone also coincides with a controversial new policy from the Minns government that, however, that on the one hand calls time on greenfield coal mining, but on the other hand greenlights coal mine extensions and expansions for a further 25 years.

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