[ViewTrick1002]

If taking that step, why charge the batteries with extremely expensive nuclear powered electricity rather than cheap renewables?

It is done when moving electricity around when the grid is strained. Buy expensive electricity and sell it at even higher prices. But that is a vanishly tiny portion of the demand.

[evandijk70]

Because there is little solar in the 3 winter months, so you would need a lot more storage for solar then for nuclear.

[pfdietz]

What is needed is an alternative storage that minimizes capex, even if that means operating at lower round trip efficiency. Hydrogen or ultra low capex thermal storage.

I'll point to Standard Thermal again here.

https://www.orcasciences.com/articles/standard-thermal