Earlier quoted context omitted.
It's an argument against renewables only when the renewables are expensive. When renewables are cheap, then nuclear is placed in an impossible situation, as nuclear either displaces the renewables when they ARE available (incurring a large marginal cost), or only runs when they aren't (forcing nuclear's large fixed costs to be amortized over much less output). It's likely that a cost optimized grid will have little o…
Unless you do solar and mostly skip wind, in which case you can build enough nuclear to run the nighttime load and solar for just the extra daytime load, then you can run the nukes 24/7. That minimizes both nuclear downtime and storage requirements. But if we're going to build a lot of wind, that still doesn't necessarily doom nuclear, if we can lower the capital cost of nuclear. The article describes some fairly sim…
Using nuclear instead of solar when solar was available would increase the cost of that power by a factor of 3 or more. That would also be insane.
Nuclear just doesn't have a place on a grid with a large renewable supply.
EDIT: You wrote:
"I agree that would be insane, which is why I said to run the nuclear 24/7 and build enough solar for the extra demand during the day."
This is case #2, using nuclear power during the day when you could have used cheap solar. It makes no sense economically at current nuclear costs.