You cannot power up solar panels at night, or wind turbines when there's no wind. As for nuclear, you don't need to stop them. Instead they provide a base load

You cannot power up solar panels at night, or wind turbines when there's no wind. As for nuclear, you don't need to stop them. Instead they provide a base load so you don't need to ridiculously overprovision other power sources. And they are flexible enough to go 50%-100% quickly: https://www.oecd-nea.org/upload/docs/application/pdf/2021-12/technical_and_economic_aspects_of_load_following_with_nuclear_power_plants.pdf https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...