Nuclear Can Dial Down/up 80% on Hourly Basis

Posted5 months agoActive5 months ago

julcol

9 points

5 comments

ft.comResearchstory

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Nuclear EnergyEnergy ProductionSustainability

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Nuclear Energy

Energy Production

Sustainability

Nuclear power plants can adjust their output by 80% on an hourly basis, highlighting their flexibility in meeting energy demands.

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Aug 20, 2025 at 4:51 PM EDT
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Discussion (5 comments)

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julcolAuthor

5 months ago

1 reply

I always thought nuclear was an all or nothing. Massive thermal inertia and hours days? to fully come online from cold start. Even if it is not coming up form cold start, this type of power balancing is new to me.

This should kill combined cycle role in the electricity mix to counterbalance renewables swings ? am I missing something ?

toomuchtodo

5 months ago

France’s nuclear fleet performs load following but it is harder on the steam mechanicals requiring more frequent maintenance. The question is if this operating model is more cost efficient versus lithium and sodium battery storage at scale for buffering generation and load, with battery storage around $52/kWh for fully integrated systems currently (LFP chemistry). They're constantly burning ~1GW of fossil gas that could potentially be replaced with grid forming battery storage, assuming nuclear output is increased.

Besides domestic battery storage, an additional challenge is that they’re transmission constrained and there is too much nuclear and renewables and insufficient battery storage for domestic demand. Additional inteconnector capacity is coming online to Ireland in 2026 though (Celtic Interconnector, 700MW HVDC submarine cable).

https://news.ycombinator.com/item?id=44867632 (citations)

https://app.electricitymaps.com/zone/FR/72h/hourly

https://en.wikipedia.org/wiki/Celtic_Interconnector

https://auroraer.com/company/press-room/frances-battery-mark...

https://ember-energy.org/latest-insights/eu-battery-storage-...

londons_explore

5 months ago

1 reply

Isn't the point that it makes no financial sense to ever turn it down?

You still need the same number of staff supervising. Still the same interest costs on the huge bank loan to build it. Still the same maintenance intervals, etc.

Might as well leave it at full power if there is any use whatsoever for the produced energy. Even if there isn't, using the energy to warm up the ocean avoids thermal cycling of the reactor core and therefore reduces maintenance.

toomuchtodo

5 months ago

If you sell power into the power market at 0 or negative prices, you’re not only paying the fixed costs, you’re paying someone to take the power. Renewables can easily curtail, they simply stop producing power when commanded to (typically based on market pricing signals).

julcolAuthor

5 months ago

https://archive.is/mMANE

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