I'd never discourage someone from buying an electric vehicle, even if they live in West Virginia. The Clean Power Plan will definitely see carbon intensity go down. There's a small but real risk of CPP being significantly reduced after the Supreme Court had a recent negative rulings on MATS. I'm no expert in the policy impacts here, but the court scolded the EPA on a portion of MATS that may have similar impacts on some portions of CPP. The low cost of natural gas is going to push some coal off the system, regardless of CPP. And, I want to put a plug in for nuclear. Its emissions are similar to renewables.
I think the court mainly said that the EPA didn't do enough due diligence when looking at the cost/benefit assessment of the plan, but that were that cost/benefit reasonable, that there was nothing inherently illegal about it. They kicked it back to the lower court for review after EPA gets their shit together. I'm optimistic that reason will win in the end.