Fossil fuels are dirty, old, inefficient, and obsolete. Besides, we'll be needing them for the raw materials for polymers and whatnot.
It's simple economics.
As is usually the case, conservatives are on the wrong side of progress into the future. They want to keep things the same but that is an impossibility. Life is change and therefore will always be at odds with conservative values.
That is precisely the side that conservatives are on: the change will happen when it makes since economically. Not because of burdensome government intervention, but because of innovation and simple economics.