Would depend on what you are trying to cover.
- Are you thinking just daytime peaking?
- Are you thinking just summer output?
- Are you thinking just winter output?
- Are you thinking overall average?
Rooftop solar in Ontario has an average CF of ~10%. How solar is viewed by our grid operator graphs like this:
View attachment 131030
So, the answer for winter would be significantly different than for summer, which would in turn be different if we were talking annual.
If we are just going by average CF, if we had 2,500MW of solar, it would be matched by 250MW of nuclear or a bit less than one GE BWRX-300 reactor. However, that doesn't capture the gas displacement that solar is doing during a summer day. However that in turn doesn't capture the fast ramp gas capacity needed above and beyond that solar capacity to cover the morning/evening ramps. So solar isn't eliminating gas capacity, it's just displacing use of it.
If we were to pair that nuclear capacity with some pumped storage, say 2.5GW of PHES, we would run the reactor steady state and use the PHES to cover the peaks and ramps, so you'd have a more complete gas displacement scenario and you are less likely to have to curtail the nuclear capacity. Of course PHES viability is geographically limited, so that is another discussion.
Is that along the lines of what you are looking for?