So people run coal plants to destroy energy?

The energy was in a state that was not useful, and to generate useful energy with it you need to keep the input of that energy source flowing.

Edit: all energy plants took some kind of useless energy and transform it to one that can be used, the thing with wind, solar and hydro is that they took energy that is already there being wasted. While carbon, oil and gas take energy that is stored in a chemical form.