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.

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leonidasrup 21 hours ago | parent [-]

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-...

	▲	ViewTrick1002 18 hours ago \| parent [-]
		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...