You have to have some base load it can’t be all renewable because renewables just aren’t reliable enough. The only way to get 100% reliability from solar for example would be to build a ring of panels around the equator (type 1 civilization stuff).
Of all the options for base load, nuclear is the least worst, at least until we can get Fusion online, but you know that’s always 20 years away.
That’s why we have hydro. Its a giant battery. We can also make synthetic methane.
We absolutely can do 100% renewable.
Hydro is great but it’s not clean it requires you to flood vast areas of land, it’s quite damaging to wildlife.
It is also highly situation dependent, you be quiet exactly the right kind of geography in order to be able to build hydro and then you require that there is no one living in the affected area otherwise it gets very expensive very quickly assuming you’re allowed to do it at all.
