For coal, this doesn't really matter - it still loses. To pick up where renewables leave off, you want natural gas (or even petroleum) turbines that can quickly be brought on and off line. Coal and nuclear are not really suited to this.
The power industry makes the distinction between "base load" and "peak load" generation sources. Coal and nuclear are best for base load, running 100% capacity as much as possible. Combined-cycle turbines are best for peak load since they can be economically throttled.
The issue is both peak and base load demands are increasing. Turbines make great peak load sources but are poor for base load. TVA -- my former employer -- took coal plants offline due to Obama-era regulations making them impossible or unprofitable to operate (or both). They made up for the lost generating capacity by running their turbines as if they were base load generators. The result? Huge increases in turbine maintenance costs, more frequent maintenance outages, and more unplanned outages.
If the goal is to kill coal you have to replace it with something. Nuclear is a non-starter for most people because of their hysterical, irrational fear of it. Natural gas is cheap but, as stated above, it's not the best candidate for peak load generation. Nothing in the solar or wind column can come close to substituting for any current base load generation technology.