[elproxy]

Nuclear doesn't need pumped hydro storage so much. France has historically been doing load following with its reactors, and the rate of modulation is of 80% over 30min. (so 24MW/min for a 900MW reactor). Sure, having a bit of pumped hydro to help for really steep spikes can't hurt, but its role is minor. Storage for renewables on the other hand...

[Retric]

I was referring to using traditional hydro to cover peak demand not pumped storage.

Anyway, reducing power output regularly is straightforward in the moment but requires reactors to sit idle for ~90% of what it costs to run at full power. That extra capacity is therefore what’s expensive. France got around that by exporting a lot of nuclear power rather than see rates spike due to that excess capacity.

Essentially you can pay between X$/kwh for nuclear on a grid with storage or peaking power plants or 2.5X$/kWh for near 100% nuclear without storage or peaking power plans. The second one is what’s completely uneconomic and gives rise to the term base load power as it’s poorly suited to cover peak demand.