With proper system design this becomes a non-problem. This adds cost, but done properly it's cheaper than a system based on nuclear, especially going forward as renewable and storage costs continue their relentless decline (at a pace nuclear could only dream of).

In more detail: you want two kinds of storage, one optimized for daily charge discharge, and one for long term storage, to handle different frequencies in the power spectrum of the power-demand mismatch curve. The first is batteries, and the second is various techologies (like thermal or hydrogen) that will be brought into play for the last 5% or so of grid decarbonization.