Australia’s biggest coal generator has plans for two massive new battery projects as utilities focus on “firm” power

AGL, one of the country three big privately owned energy utilities, and still the biggest coal generator, has revealed plans for two new massive battery projects, including one that will rate among the biggest in Australia’s main grid.

The company has only just completed the 500 megawatt, 1,000 MWh Liddell battery at the site of its shuttered coal fired generator in the Hunter Valley, and it is also building a 500 MW, 2,000 MWh battery next to the Tomago aluminium smelter near Newcastle.

Now it has filed plans for two new battery projects, both located at key substations along major transmission lines. One, a 350 MW, 1,400 MWh in the Kangaroo Valley south of Sydney, has already entered the federal EPBC environmental assessment.

Another, the Bathurst battery west of Sydney, is its biggest to date, sized at an operating capacity of 500 MW and 4,000 MWh, but with planned installed capacity of more than 5,400 MWh to deal with redundancy over the 20-year life of the project.

That Bathurst battery is interesting because of its size, and the fact that it is an eight-hour battery. AGL started its battery adventure with two one-hour batteries at Broken Hill in NSW and Torrens Island in South Australia, moved to 2 hours at Liddell and then four hours at Tomago.

The eight hour proposal at Bathurst is in line with new industry trends, driven by the falling cost of battery modules and the changing needs of the market, and will also be sited close to the proposed Mt Piper battery next to the coal plant of the same name operated by EnergyAustralia.

The Bathurst battery would be located six kms from the town at Eglington, along the route of an existing 330 kV transmission line, with construction expected to start in late 2028 and full operation in 2030.

AGL proposes to close its Bayswater coal fired generator in 2022, although the market has little faith in the timelines of any of the proposed coal closures at the moment.

“Batteries are part of our strategy to replace coal-fired power stations with more flexible energy storage,” the company says in a fact sheet posted on its website.

“Batteries can respond quickly to address an energy shortfall, supply the grid, and stabilise it. As the amount of renewable energy increases, batteries are very important as they allow excess energy to be stored.

“Batteries are essential to building a more reliable and resilient energy system.”

The Kangaroo Valley battery is also proposed near the small town of the same name, and close to a major switching station and under an existing 330 kV transmission line.

Its EPBC application says upgrades will be made to the adjacent Old Bendeela Road as well as to nearby intersections. An approximate 1.2-kilometre-long underground transmission line will run to the nearby Kangaroo Valley 330Kv switching station.

A scoping report filed with the NSW government in late 2024 canvasses a 400 MW, 1,600 MWh battery project and also suggests that other battery technologies such as sodium and flow batteries could also be considered.

If approved, AGL expects the battery to improve the reliability and stability of the local grid, as well as create up to 150 jobs during peak construction and 3 ongoing jobs once operational.