Nuclear might have been an answer ten years ago, but one cannot make the case today that it is the answer. The raw economics have pushed nuclear out of the picture now.
Renewables + storage. For long term storage and covering rare extended dark windless periods, the key is hydrogen, for which the cost per kWh for underground storage can be far lower than for batteries (efficiency is lower, but that's ok.)
If you go to https://model.energy/ and optimize such systems in various places, using real weather data, you find nuclear (called "Dispatchable 2" in the advanced options) get optimized to 0%. It's just too expensive. That site uses plausible cost numbers, except electrolysers are already cheaper than their target cost for 2030.
