CSIRO’s latest GenCost report shows battery costs falling fast, wind costs stabilising and coal, gas and nuclear lagging well behind. For the seventh year running, firmed renewables remain the lowest-cost path for Australia’s electricity system.

CSIRO’s latest annual GenCost report has revealed fresh plunges in big battery costs and a welcome dip in the cost of onshore wind, while also confirming – for the seventh year in a row – that a mix of firmed renewables is the cheapest way forward for Australia’s electricity system.

CSIRO, Australia’s premier science agency, and the Australian Energy Market Operator (AEMO), have collaborated on the annual GenCost report since 2018, when the first report was produced after being commissioned by the then Coalition government.

It was designed as an effort to deliver a “policy-neutral and technology-agnostic assessment” of cost data for new-build generation and storage technologies to underpin electricity system modelling and planning. Its conclusions have been consistent – renewables and storage are the lowest option.

The draft GenCost 2025-26 Report, released for public consultation on Wednesday, finds that big batteries are once again the star performer on capital cost reductions, charting another expected 15 per cent fall, year-on-year, to back up the 20 per cent fall in 2024-25.

In a turn-up for the solar books, large-scale solar PV costs have been revised upwards by 8 per cent for 2025-26, compared to an 8 per cent fall in 2024-25. CSIRO says this represents a reversal of the last two years of gains but likely reflects cost volatility rather than a new trend.

But it is onshore wind that has provided perhaps the biggest about-face, with capital costs charting a 5 per cent drop over the 2025-26 period and showing “tentative signs of stabilising” following the 35 per cent jump in 2022-23.

“As the historical data indicates, onshore wind is one of the technologies which has been most impacted by recent global inflationary pressures,” the report says. “[The] updated data indicates that the costs pressures are stabilising.”

This is a welcome development for the Australian market, where rising costs, planning delays, and

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