In short:
Pacific Green has won approval to build South Australia's largest battery storage project near Mount Gambier.
It says the project will improve grid stability, reduce power prices and cut greenhouse gas emissions.
What's next?
Pacific Green is also looking to build a similar plant in Portland, Victoria.
The South Australian government has granted planning approval for the largest battery storage project in the state.
Pacific Green says the Limestone Coast Energy Park, which will have a capacity of 1,500 megawatt hours, will significantly strengthen the region’s grid stability, reduce power prices and cut greenhouse gas emissions.
If successful, the battery will eclipse the high-profile Hornsdale Power Reserve in South Australia's Mid North that was built by Elon Musk's company, Tesla, in 2017.
The latter battery, colloquially known as the "Tesla battery", can store up to 193 megawatt hours (MWh) and was once the world's biggest.
Seven years after it made international news, it's not even the state's biggest.
As of August 2023, that title has belonged to AGL's battery at Torrens Island outside Adelaide, which has a capacity of 250MWh.
The new 'mega' battery?
The new park will be located just north of Mount Gambier, at Mingbool, and will store power to discharge during periods of high demand.
The company expects to begin construction in the fourth quarter of the year, with the first phase of the project to be operational in 2026.
Managing director Joel Alexander said the batteries would store energy for when power prices and demand were high.
"We all know cost of energy is going up," he said.
"This energy park will directly reduce wholesale prices and also offset a significant amount of carbon dioxide."
The site is located near the electricity interconnector between South Australia and Victoria.
It will be able to provide power to the South East if the line goes down.
"It will play an important role in keeping the lights on in the South East region in the event the interconnector was to go down and power was lost between the two states," Mr Alexander said.
State Energy Minister Tom Koutsantonis said it was good to see more battery storage being built in the South East to "strengthen our security of supply and reliability".
Pacific Green is also planning another energy park at Portland, in Victoria, and is looking for a second site in SA.
Diesel power stations closing
Engie's 63-megawatt Snuggery diesel power station near Millicent and another based at Port Lincoln were removed from service on July 1.
They will both close completely in 2028.
Curtin University sustainable energy systems expert, Liam Wagner, said the mothballing of the Snuggery power station should not impact the region's electricity reliability.
He said it only operated for a few hours each year and could be restarted during periods of peak demand.
"It might take several hours to be able to do that, rather than just being a diesel generator that can be switched on at any given moment," Dr Wagner said.
"It would need to be given notice to be able to switch on, but it's still possible and they have a sufficient fuel supply to be available."
Big battery state
The new project is one of several new batteries being proposed or under construction in South Australia, including Epic Energy's recently announced 200MWh Mannum project in the Riverlands.
In 2020, the state's 194-megawatt Tesla-built battery in Hornsdale, near Jamestown, made international news when it became the largest lithium-ion battery in the world.
Its original 2017 installation by Elon Musk's company happened after the billionaire used Twitter to promise he could build it in "100 days or it's free".
It would eventually secure approval from the Australian Energy Market Operator (AEMO) to deliver grid-scale inertia services to the National Electricity Market, but the project has not been without controversy.
In 2022, the Hornsdale Power Reserve was fined $900,000 for failing to provide grid stabilisation services as required in 2019.
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