Earlier quoted context omitted.
Nuclear runs constantly. Solar and wind don't. This is a significant problem. Storage is hard and inefficient. We don't currently have a viable complete renewable solution. Nuclear is much better for the planet than fossil fuels and is the only option to bridge the gap required to operate the current renewables.
Storage is not, in fact, hard. Its efficiency is not important beyond a few hours' worth, because it is rarely needed. For those few hours, battery efficiency is very good.
I'm not aware of any significant battery based storage system deployed at scale that solves this problem. There are some large battery banks but none even close to the scale required. It's a hard problem as it would require a huge increase in global manufacturing.
I'd like to be wrong here. I'd love it if it was possible to build an affordable grid based on 100% renewable generation. It will be possible one day. I look forward to that day.