Where does your estimated cost of the BESS (AUD 80 Billion) come from. This is £40 billion for 8GW of BESS, £5 million / MW. That seems incredibly expensive in the UK when I was working in the market 2 years ago we were looking at c. £800k / MW.
My fairly recent Aus cost ref point is Waratah, 850 MW / 1,680 MWh, which per various internet sources [links below] was anywhere between around AUD 700 million and AUD 1.1 billion. I like round numbers, so I ran with AUD 1 billion.
If you have shareable sources of fairly recent total UK project costs per MW & per MWh I'd be very interested to see them. I've tried searching on recent large UK BESS projects but I haven't seen total project cost info.
I think you've got what I said in my post confused.
Figure 4 [link 1] shows the OE map of the NEM and its 'operating' BESSs.
You can see they are distributed across virtually the whole NEM, from S. Aus thru Vic and NSW to Qld. {Only Tas doesn't have any BESS coz Tas runs on controllable Hydro.} You can also see I estimate 2 hours average for the ‘operating’ 6,195 MW ≈ 12,000 MWh. That's current ‘operating’, developed over the last ~decade, and I have no idea of the cumulative cost of those 51 facilities. But I *do* know the Waratah facility was around AUD 1 billion, and it's a recent addition, so it *should* be a good indicator of the whole cost of one new 850 MW / 1680 MWh facility.
Figure 5 [link 2] gives an indication of how much *future* BESS capacity would be needed to smooth the to-date record whole-NEM one-day Solar generation. That was 222,329 MWh thru 09 Dec 2025. Constraining that future BESS operation to between minimum 10% SoC and 90% maximum SoC, and using the one-year average NEM RTE = 80% (see Note 1 in the post) I get a required future BESS capacity of just over 135,000 MWh = 80 x Waratah's 1680 MWh. Ergo, future cost AUD 80 Billion. I check the power flow the future BESS would need to cope with in this model: 14,291 MW, well within the power capacity of 80 x 850 MW of 80 Waratahs.
There are 3 massive transformers at Waratah, each designed to take one third of the full power.
One of the three has failed 'catastrophically' according to the news reports, and a second unit had some worrisome indications when they were doing testing so they're concerned it has the same design weakness as the first failed item.
Look at he low points like a fence or a flood levee. Windless lights are the weak links in the RE cain.
https://www.flickerpower.com/index.php/search/categories/renewables/21-7-intermittent-solar-and-wind-power-can-displace-coal-but-cannot-replace-it
Where does your estimated cost of the BESS (AUD 80 Billion) come from. This is £40 billion for 8GW of BESS, £5 million / MW. That seems incredibly expensive in the UK when I was working in the market 2 years ago we were looking at c. £800k / MW.
Thank you, RobB.
My fairly recent Aus cost ref point is Waratah, 850 MW / 1,680 MWh, which per various internet sources [links below] was anywhere between around AUD 700 million and AUD 1.1 billion. I like round numbers, so I ran with AUD 1 billion.
If you have shareable sources of fairly recent total UK project costs per MW & per MWh I'd be very interested to see them. I've tried searching on recent large UK BESS projects but I haven't seen total project cost info.
3 links:
1. https://reneweconomy.com.au/filling-eraring-gap-giant-waratah-super-battery-project-to-receive-more-than-700m/ includes this: "The cost of the actual battery is likely to be much more than $700 million – probably double that "... but article Dec 17, 2023
2. https://www.energyconnects.com/news/renewables/2025/august/australia-activates-blackrock-s-a-1b-super-battery-which-will-be-world-s-most-powerful/ Aug 2025
3. https://www.nbnnews.com.au/2025/04/07/exclusive-look-inside-the-1-1b-waratah-super-battery-project/ Apr 2025
Thanks for the response Chris.
So Warath based on A$1.1bn for 850MW is A$1.3M / MW.
That would make 8GW of BESS which I think you have indicated is what is installed in South Australia just over A$10bn.
So I still don't see where you have got your figure of A$80bn from.
This is a factor of 8 different and somewhat better value than your post has indicated.
Hi RobB,
I think you've got what I said in my post confused.
Figure 4 [link 1] shows the OE map of the NEM and its 'operating' BESSs.
You can see they are distributed across virtually the whole NEM, from S. Aus thru Vic and NSW to Qld. {Only Tas doesn't have any BESS coz Tas runs on controllable Hydro.} You can also see I estimate 2 hours average for the ‘operating’ 6,195 MW ≈ 12,000 MWh. That's current ‘operating’, developed over the last ~decade, and I have no idea of the cumulative cost of those 51 facilities. But I *do* know the Waratah facility was around AUD 1 billion, and it's a recent addition, so it *should* be a good indicator of the whole cost of one new 850 MW / 1680 MWh facility.
Figure 5 [link 2] gives an indication of how much *future* BESS capacity would be needed to smooth the to-date record whole-NEM one-day Solar generation. That was 222,329 MWh thru 09 Dec 2025. Constraining that future BESS operation to between minimum 10% SoC and 90% maximum SoC, and using the one-year average NEM RTE = 80% (see Note 1 in the post) I get a required future BESS capacity of just over 135,000 MWh = 80 x Waratah's 1680 MWh. Ergo, future cost AUD 80 Billion. I check the power flow the future BESS would need to cope with in this model: 14,291 MW, well within the power capacity of 80 x 850 MW of 80 Waratahs.
Hopefully that clears it up for you.
link 1 https://chrisbond.substack.com/i/186876288/figure-4-operating-besss-on-the-nem-as-of-07-feb-2026
link 2 https://chrisbond.substack.com/i/186876288/figure-5-smoothing-nem-solar-power-using-besss
Sorry to be so thick but does 1oo3 ("1oo3 wrecked, 1oo3 too suspect") mean 1 out of 3. Is it the same one?
Hi Jim, not your fault, I was guilty of jargon.
There are 3 massive transformers at Waratah, each designed to take one third of the full power.
One of the three has failed 'catastrophically' according to the news reports, and a second unit had some worrisome indications when they were doing testing so they're concerned it has the same design weakness as the first failed item.
This link is to the latest news I can find on it:
https://www.pv-magazine-australia.com/2025/11/26/akaysha-provides-waratah-update-still-opaque-on-transformer-failure/