‘Reliable’ wind power: what cost battery storage?

The Tesla Hornsdale 'big battery' in South Australia is claimed to be able to discharge 194 MWh from fully charged to zero. For NEM storage, capacity of 65,223 – 130,447 Hornsdales would be needed just for seasonal storage and discharge (ignoring efficiency losses).

That's expensive. If, as claimed, a Hornsdale 'big battery' costs $90 million, and batteries last 20 years, the cost is (Australian dollars) $5,870,070 million (A$5.9 trillion). If the batteries only last 10 years, the cost is A$11,740,140 million (A$11.7 trillion).

Technology improvements and scale operations likely will cut unit energy storage costs a lot. Suppose such costs fall to an average of just 10% of the cost of the Hornsdale SA 'big battery'. At between A$0.6 trillion and A$1.2 trillion, seasonal battery storage is still very costly.

Before allowing for the extra costs of needed wind turbine capacity, and new specialised transmission capacity everywhere, such battery costs for the NEM under a 100% wind plus 100% batteries regime are still ruinous.

Either seasonal reliability is sacrificed, or customer costs soar even more. Or both.

I've not allowed for other incipient electricity demands, such as those driven by AI, cryptocurrencies, electric vehicles, 'green' production of various 'green' metals, electrolysed hydrogen, and the like. These would magnify renewables power supply problems.

I'm sceptical about 'distributed' renewables generation and transmission, and so-called 'demand response' (really a euphemism for power rationing). Who pays for all that, anyway?

Switching to a 'reliable' wind-only policy for the NEM is a major structural inflation driver with decades still to run. Australian living standards, inevitably, will fall more.

The economic realities of intermittent wind power, plus the growing demand for maintaining reliable electric power, will force consideration of alternatives.

Even if unit costs of storing energy in batteries fall to 10% of the Hornsdale 'big battery' cost, the total cost of investing in the reliability-required number of Hornsdale-equivalent energy storage units won't happen.

Wind power is less ruinous than solar. It's less intermittent, on average. It's still not nearly base-load reliable, however.

100% reliance on wind turbines and battery storage won't happen. Why?

At 10% of Hornsdale costs, battery costs would average half the dollar value of Australian GDP.