I am not talking about base load. I am talking about peaker plants. They are more expensive to run because they aren't on continuously. Batteries are far more efficient at shaving peaks without requiring excess capacity. You do need more batteries for renewables because of their intermittent nature. But it is true that you are going to build some of that storage anyway to save money on maintaining peaker plants.

That is actually what the majority of battery installations have gone to so far.