[hathchip]

> and doesn't require associated (not yet existing) massive storage.

That's not quite true. Nuclear generation is more flexible than wind and solar but much less flexible than thermal fuels, particularly gas. Although you can choose when you turn a nuclear power station on and off, you can't do so quickly, and your choices are somewhat constrained (regular downtime is required).

Nuclear worked well in the energy mix when it supplied base load (ie generate roughly the minimum daily load at all times) while coal supplied predictable peak load and gas could supply unexpected peaking. As this mix changes, availability patterns of nuclear start to be more of a burden. In a system without fossil fuels, you would have to have (some) energy storage, regardless of the split between nuclear, solar and wind.

The exact number for how much storage, how much overcapacity, or how much natural gas generation you would need vary with the proportions of solar, wind and nuclear of course, but it's an oversimplification to suggest that they are trivial if you use mainly nuclear.

[MagnumOpus]

To simplify without oversimplifying: Modern nuclear plants can change between 30% and 100% of nameplate capacity within half an hour, and that's how they operate in France for instance. While coal plants might rev up from 75% to 100% in a twice-daily shift change, but are clearly not set up to run at minimal loads.

https://en.wikipedia.org/wiki/Load-following_power_plant#Nuc...