[jmyeet]

> But overall, for the same £20bn a year you could have probably built 5 Hinckley Point C sized 3.2GW nuclear plants concurrently (assuming £4bn a year capex for 10 years).

Planning began for Hinkley Point C in 20113. It was approved in 2016. Construction commenced in 2017-2018. It's hit major delays and is currently projected to come online in 2030. It could be delayed furhter. Unit 2 is expected about a year later [1]. Cost have ballooned to almost £50 billion [2] and may balloon further.

So you're looking at almost 20 years to build, £50 billion in costs and electricity production of ~3.2GW.

AFAICT that 3.2GW is ~7% of the UK's current electricity requirements so I'm not sure where you're getting "nearly all electricity demand". Also, 5 Hinkley Point Cs would be 16GW of electricity not 30GW.

Hinkley Point C has a contracted price of £133/MWh. I imagine there's some risk-sharing and inflation in the contract so this will probably go up. Compare this to £65/MWh for new solar and £72/MWh for new onshore wind [3]. Plus of course that wind and solar projects don't take 20 years to come online.

Lastly, the only way the per MWh costs can even get that low is by giving Hinkley Point C a 60 year lifespan to amortize the cost over a sufficiently large timespan. It's likely that as the plant ages, operational costs will significantly increase beyond what's projected.

[1]: https://eandt.theiet.org/2026/02/23/hinkley-point-c-faces-fu...

[2]: https://www.telegraph.co.uk/business/2026/02/20/hinkley-poin...

[3]: https://www.carbonbrief.org/qa-new-uk-onshore-wind-and-solar...

[martinald]

Yes of course it's hit major delays, but my point is in hindsight had we started 5 nuclear plants (sort of as planned) around HPC construction start instead of spending the money on renewables, we'd have 5 plants coming online in (say) 2030. This would be nearly 50% of the entire UK supply. Another ~10 years later you'd have another 5, giving ~30GW of baseload.

And there's no reason we couldn't have used other reactor designs, apart from lack of financing so only EDF gambled everything on the EPR for HPC (again) and failed to deliver on time/on budget (again).

>Hinkley Point C has a contracted price of £133/MWh. I imagine there's some risk-sharing and inflation in the contract so this will probably go up. Compare this to £65/MWh for new solar and £72/MWh for new onshore wind [3]. Plus of course that wind and solar projects don't take 20 years to come online.

In 2012 prices HPC was £89/MWh. AR7 is delivering (in 2012 prices) offshore wind for ~£65/MWh.

But regardless these aren't comparable at all, for the reasons I set out above. That £65/MWh often doesn't include grid upgrades (which aren't required to nearly the same scale for nuclear, as they tend to be nearish existing population/demand centres and have existing grid infra). AND you still need (expensive) backup for that wind. We are building (right now!) new gas peaking plants that are allowed by law to only operate 10 days per year. The cost per MWh if you include that capex is horrendous.

>Lastly, the only way the per MWh costs can even get that low is by giving Hinkley Point C a 60 year lifespan to amortize the cost over a sufficiently large timespan. It's likely that as the plant ages, operational costs will significantly increase beyond what's projected.

Not true, HPCs 'agreement' is for 35 years. After that they just get the market price, so it is not based on the 60 year lifespan per se.

[jmyeet]

The UK's grid upgrades are a mix of the shift to renewables but also to handle anticipated increased demand, which will be needed regardless of the electricity source or location. I don't know what the mix is however.

> Not true, HPCs 'agreement' is for 35 years. After that they just get the market price, so it is not based on the 60 year lifespan per se.

Isn't this conceding the point that costs are going to go way up as HPC ages? Why else would you have a 60 year lifespan on a plan but 35 years of agreed pricing?

[martinald]

UK peak power demand has _reduced_ by 15GW in the past 20ish years.

Obviously there is some investment needed but if you take a look at the capex cost of the north Scottish grid upgrades PLUS the HVDCs it's pretty terrifying.

The idea is that the financing will be "paid off" after 35 years so it doesn't require a "guaranteed" price after that (it reduces finance costs significantly when HMG is underwriting the main payback period. I expect the remaining 25 years will be extraordinarily profitable for EDF. Even if there is more maintenance costs they will have no finance costs. And finance is the main cost of HPC (60-70% goes to interest payments on the debt).

[adrianN]

Peak electricity demand will go up quite a bit as we replace fossil fuels for transportation and heating.