As far I understand, the Onslow battery project generates power, admittedly peak but still a generator.
The CBA for this project was utter crap, it was back in the early 2000s when it was first looked at and still is. Pig, lipstick etc.
A P50 of $16b, so maybe when we get to a P90 if ever, the cost would be at least double and no amount of contingency will cover that off. Plus 20 years for production.
Spend the money on modular nuclear and if that's not possible due to the sook brigade, ramp up Geothermal and Hot Rocks.