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Comment by mono442 | Hacker News Reader

The way the EU forces the electricity market to operate makes them completely unprofitable. Renewables are always given priority in the market, which results in other power plants operating at a capacity factor of 30-40%. Since nuclear power plants are mostly capital expenditure-intensive, this makes the electricity they produce absurdly expensive.

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Because the way how the EU electricity market operates first to supply electric power are the power plants with the lowest operating costs. This are usually renewables and nuclear power plants. Both are capital expensive and cheap in operating costs.

Usually the capacity factor of European nuclear reactors is higher than 60%.

olkiluoto-3 nuclear reactor, had capacity factor 70% in the year 2024: https://world-nuclear.org/nuclear-reactor-database/details/o...

Mochovce-3 had capacity factor 74% in the year 2024: https://world-nuclear.org/nuclear-reactor-database/details/M...

In the U.S. they really try to get maximum from nuclear reactors. https://world-nuclear.org/nuclear-reactor-database/details/W...

That’s just a consequence of how they bid. The marginal cost for a renewable plant is zero. It’s non-zero for nuclear power.

But nuclear power don’t want to shut down since that both increases wear and tear and makes them unable to capture revenue when the prices become higher again.

So they bid negative expecting to eat the losses and let more flexible plant shut down first.

Operating costs of wind power are for sure not zero. Especially repairs of offshore wind turbines are very expensive.

https://docs.wind-watch.org/offshore-availability-costs.pdf

Hydropower and solar have much lower operating costs.

All thermal power plants experience wear and tear and have to be regularly repaired and maintained. Nuclear power plants can load-follow (within technical limits), but as the operating costs (maintance, repair, staffing, fuel) are much lower then capital costs it makes economic sense to run them at full power.

https://shs.cairn.info/revue-revue-deconomie-politique-2025-...

You have to distinguish between fixed O&M and the extra cost that comes from an extra hour of running.

I’ve been googling and using LLMs and there’s no literature on the subject, but the companies owning them effectively treats it as zero.

In government models they seem to have landed at €1 per MWh.

The best estimates both Claude and ChatGPT came up with was both ”low single digit € per MWh”.

This report was linked, and ARUP the author did not get any replies when they asked the offshore wind companies this question.

https://assets.publishing.service.gov.uk/media/6966a5c7e8c04...

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