As an example of extreme years which you have to solve for try.
nature.com
The p/reviewed paper says a zero-nuclear/carbon EU grid needs 55 days of energy storage.
Given our tiny remaining carbon budget and the UK expanding storage from 1 to just 4 hours over 8 years, a back-of-envelope calc shows battery capacity must scale 300x
#NoEasyTransition
#aRadicalFutureAwaits