Stanwell snaps up final share of giant Brisbane battery, firming up plans for life after coal

Queensland government-owned Stanwell Corporation is seeking to buy the full output from the final stage of the massive Supernode battery energy storage project near Brisbane, as it builds a firmed renewable energy portfolio to replace its baseload, coal enterprise.

Stanwell revealed on Friday it is proposing to secure a 15-year deal with Quinbrook Infrastructure Partners to buy 100 per cent of stored energy from stage three of its Supernode Battery Energy Storage Project in Brendale, adding 250 MW and 1,010 MWh (just over four hours) to the state-owned generator’s portfolio.

The Supernode project is being built by Quinbrook in Brendale, just north of Brisbane. The battery energy storage system (BESS) consists of three 250 megawatt (MW) stages, each with different amounts of energy storage duration. Construction of stage one is currently underway.

The site was chosen for its location next to the central node of the Queensland transmission network, adjacent to the South Pine substation at Brendale, and redundancy with the support of three separate high voltage transmission connections. It’s part of a $2.5 billion “green” data centre powered by renewables and battery storage on a 30-hectare site.

Origin Energy has signed up for all of the capacity for both the first and second stage of the project – totaling 500 megawatts (MW) and 1560 MWh – in preparation for the closure of its Eraring coal plant in NSW between 2027 and 2029.

The 15 year deal proposed by Stanwell includes a contra arrangement: Quinbrook will entertain the potential involvement of the new Stanwell Asset Maintenance Company (SAMCo) to handle operations and maintenance. 

The Queensland coal power station operator set up the O&M arm at the end of 2023 and has been signing up clients over the past year, including with Ratch Australia to look after its 42 MW Collinsville solar farm near Townsville and the two-stage 500 MW Wambo wind farm being built in Queensland’s Western Downs.

The offtake agreement for the Supernode BESS will be helpful for Stanwell’s commercial and industrial customers which are looking to decarbonise their operations, said the company’s CEO Michael O’Rourke.

“The proposed arrangements would enable Stanwell to have 2.8 GWh of renewable energy storage committed by 2027, which means we are well on our way to achieving our objective of 5 GWh of firming assets by 2035,” he said in a statement.

“It is another milestone announcement in our renewable transformation and would assist in delivering on the Queensland Government’s renewable energy targets of 70 per cent by 2032 and 80 per cent by 2035.”

Big batteries getting bigger

The Supernode offtake deals are a first for both Origin and Stanwell. 

Origin is developing its own batteries at its Eraring and Mortlake power stations and the Supernode arrangement is its first battery offtake. In July, the company doubled the size of the Eraring BESS to 700 MW and 2103 MWh, while the 360MW solar farm and 300MW, two-hour big battery in Mortlake won planning approval last week. 

For Origin, it’s the first battery offtake and for Stanwell it was the first battery offtake with a private operator. 

Stanwell is building the 300MW/1200MWh Tarong BESS and the  300MW/1,200MWh Stanwell power station BESS which saw its duration quadrupled in May. 

It’s aiming to have those two batteries active in the market in 2027.

The company has 3.3 gigawatts (GW) of coal fired power in its portfolio with the Stanwell and Tarong power stations, or about 40 per cent of the coal generation in Queensland. It fuels these with coal from the Meandu and Curragh mines, and has options to develop two other coal deposits nearby. 

With these sites subject to the Safeguard Mechanism, which requires baseline emissions to ratchet down by 5 per cent a year or pay a $75 a tonne carbon price, the company is on notice to decarbonise.