Coal is abundant, cheap and can be burnt cleanly. At least it can if the nutjobs in the government get out of the way. The problem is that once a mine is closed, reopening it is almost impossible. Due to normal chemical reactions in the mine, they fill with carbon monoxide, and methane. Both of which then have to be pumped out and fresh air pumped in. Doing this has two main problems. Carbon Monoxide is heavier than air and settles into low spots making it hard to get out. The second is easy for even liberals who have lit their farts know, methane is explosively flammable.