Earlier quoted context omitted.
For the benefit of the bystander: this person actually has no idea what energy seen planning looks like in real life. Economic optimization is absolutely at the core of it. Energy System Models (Essen) are economic optimization models. Depending on country and climate, the factor of the sibling comment of 50% is absolutely realistic. Also these details don't really matter: Storage is a viable solution to the problem…
Not sure whether you understand the difference between the prospective world of public analysts, and actually running a power grid. I know there can be a divide between the two, and some self-agrandizement on each side. Picking reliability over efficiency is the sound economic choice. Please note that my comment is not about the viability of storage for renewables.
Security of Supply is yet another issue.
Anyway, if you can use storage to lower you nuclear costs by 5% overall, would it not be used? If your comment is not about viability of large scale storage, then what is it about? Storage is dispatchable, and an economically optimal 100% renewables grid will have a peak capacity far above actual peak demand, meaning it's typically curtailed (or you run electrolysers which again can beade dispatchable and grid-forming as loads) which again means you have plenty of ability to react.
Resilience research tends to favor decentralized solutions as well. Look at how Puerto Rico is being rebuilt.