My limited understanding is that (this is France and Spain FWIW) nuclear centrals way back were built to provide energy as a first source, non-stop. Wind and s

My limited understanding is that (this is France and Spain FWIW) nuclear centrals way back were built to provide energy as a first source, non-stop. Wind and solar energies are not stable and can grant all the supply. So, at least in France, there has been at least one nuclear central that was adapted as "backup energy". It could start/stop in one minute and increase every minute the amount of energy by a lot, but I do not remember the numbers right now, sorry. All in all, and, as I said, with my limited understanding, nuclear energy could be ok as a backup of energy if the centrals are adapted or built on purpose for it, favoring clean energy when possible. In Spain, a windy day a few years ago could give you around 40% of the supply for that day. There is also solar energy. But do not forget, these energies are not a panacea: some days are windy or sunny but others are not and the supply is much lower. It looks to me like there is a lot of politization around this and people keep repeating "wind, solar" as if that granted the supply. That is factually wrong, I am pretty sure since I consider my sources of information reliable (people close to me having worked around 16 years in the energy market exclusively).