> You need both

Why do you need both? It's possible to get 99.99% reliability with wind & solar & batteries & weather modelling. There are multiple ways to handle a week long dankelflaute without nuclear: overbuilding, continental scale distribution, lots of batteries, etc. All are cheaper than nuclear.

It's also virtually impossible to get more than 99.99% reliability out of any grid, even a nuclear dominated one. Local distribution has many single points of failure.

How much do those batteries cost and can they supply power for multiple days or a season if your renewable sources aren't providing like normal?

Not to mention the environmental damage from producing and disposing of batteries.