Emissions controls counts as a regulation. That on it's own is a substantial cost. I think you're using a narrow definition of the word regulation. Not knowing

Emissions controls counts as a regulation. That on it's own is a substantial cost. I think you're using a narrow definition of the word regulation. Not knowing what the next administration is going to change adds cost of uncertainty. If it weren't due to regulation, that would mean it's due to technology or raw cost. Both of which are ruled out by the fact that the US is the third largest coal exporter in the world, and exports have increased in the last 3 years. If our coal weren't cheap, it wouldn't be worth exporting. If coal power plants weren't cheap, developing countries would be switching to the cheaper technology.