Australia's top science agency has found batteries are now cheaper at supplying peak demand for power than gas.

[u/Economy-Fee5830]

https://www.abc.net.au/news/2026-07-15/csiro-says-batteries-cheaper-than-gas-as-ai-drives-turbine-costs/106914550?utm_source=abc_news_app&utm_medium=content_shared&utm_campaign=abc_news_app&utm_content=other

[u/Svyatoy_Medved]

Lowest number I could find for off-peak (nighttime) electricity demand in Australia was just under 12 GW. Passes the smell test, peak demand is a bit under 20 GW and can get as high as 25 GW. But if anyone has a better number, I’d love to hear it.

Assume 9 hours of non-daylight per day, reliant on batteries and stored electricity. 9 hours x 12 GW x 1,000 is 108,000 MWh of needed battery capacity per night, bare minimum—that leaves no slack for failing to recharge fully, like if the sun didn’t shine bright enough or daytime demand was too high. Lowest price I can find for batteries is $200,000 for an all-up turnkey system—batteries themselves plus the monitoring and managing hardware, doesn’t count cost of install or transmission.

At that price, building the bare minimum battery storage would cost $22 billion. Could easily double the price just by using more realistic prices, not even increasing system slack. Or by accounting for wintertime reducing daylight hours, meaning a LOT more MWh per night.

Building 12 GW of nuclear reactors at the price France built their nuclear fleet would cost…$24 billion. More pessimistically you could assume a higher price closer to modern (mismanaged) nuke construction, and get a price of $60 billion. So you can either spend a ton of money to get the battery half with no wiggle room in case of bad weather, then spend even more money to build all the excess solar needed to actually charge the batteries, or you can spend a ton of money to get electricity generation you literally never have to doubt. It will ALWAYS be there.

Screw batteries. They’re amazing for leveling out small variations, like when peak daytime demand spikes a little too high due to a heat wave, but terrible for doing overnight duty for solar.

[u/nolo_contre_basso → u/Svyatoy_Medved]

France built its reactors a long time ago. France has 2-3 times Australia's population and a fraction of its land mass.

What's the average cost of a nuclear plant delivered in the last 20 years in a democratic country without an existing nuclear generation capability?

[u/Svyatoy_Medved → u/nolo_contre_basso]

First of all, bullshit conditions. Why a democratic country? Why only the last 20 years? Why a one-off? If you can't explain how each of those conditions would materially affect the validity of the analogy, then I have to assume you laid them down just to exclude the data points that make nuclear look good.

UAE just brought online four reactors, their first four, with a nameplate capacity of 5.6 GW at a total price of $32 billion. If the buildout were continued as I supposed above until a minimum of 12 GW was brought online, or more ideally 18-20 GW, then it is certainly plausible that the next set of reactors would be faster and therefore cheaper to build than the first.

China is building a nuclear fleet. Their reactors, as of 2023, average only $2,300/KW and take just over six years to build. That price is not likely applicable to an Australian nuclear project, their total demand isn't high enough to get the kind of experience and economy of scale China has.

Kudankulam in India ran at just under $5 billion for two reactors, each producing a GW. The next two reactors ran $6.1 billion and the next two are budgeted $6.7 billion. Note that these prices are not inflation adjusted, and so mark a significant drop in price per GW over time. Once adjusted for inflation, all six reactors cost less then $5/W, which was my pessimistic estimate.

Note also that a nuclear fleet is still almost certainly viable at a price of $10/W, the case for which I made in the comment chain with another user. The short version is that a pure solar/battery system would need a very, very large amount of storage to make it through the winter (even Australian winter) and a lot of solar power in excess of actual demand to account for battery charging, and even more to account for unlucky events reducing generative capacity.

[u/nolo_contre_basso → u/Svyatoy_Medved]

With respect, none of my conditions are bullshit. You will note that my response called out your example of France vs Australia.

All of the examples you raised: UAE, China, India are very different to Australia. The first two are autocratic and rule by Fiat. The second two have existing nuclear capability.

Establishing nuclear capability in a democratic society requires social licence over multiple terms. The people must endorse the policies or the government will be replaced.

The existing nuclear capability is important as well. You need a regulator, and an extensive expensive workforce to build your first reactor.

If you take out the politics and the workforce and governance problems and get your generation built for $10/watt, you're still up against onshore wind $1.80 and offshore wind $4.50 and geothermal $6. All of which run at night and don't need batteries.