This assumes that you're power generation always matches demand through time. If you had a sudden spike at night that you don't usually have (like in Texas where people kicked on their heat unexpectedly) and you were using solar, the mismatch would exist and you wouldn't be able to meet the load.

Exactly. You need natgas peakers (that aren't frozen) or charged batteries to deal with this. Nuclear, wind and solar are all unsuitable for this situation.

What do you think of the claims of user "corty" elsewhere in this thread, who seems to say that nuclear isn't unsuitable for this situation?

The primary problem with nuclear is the fact that it's insanely expensive. If you're not running it flat out 24/7, then the cost per MWh goes up dramatically.

Of all the other energy sources, it's the only one where we have to put serious consideration into warning people not to dig up the waste, and how to keep them from doing it thousands of years from now.

Or turbines burning hydrogen.