Solar and wind are intermittent
Solar and wind are as noncompetitive as they are intermittent.
Solar and wind alone can’t quickly replace all coal power plants, due to their main downside: intermittency, i.e., when the sun doesn’t shine or the wind doesn’t blow.
Compensating for such crunch-times can only be achieved with:
-supergrid expanding the distribution of renewable energy from the US windy Midwest to nightlife in the Northeast;
-cheap batteries storing electricity from solar or wind peak production;
-base-load power plants running on coal or nuclear.