China is trying to become oil-independent by all means necessary. All their means of accessing oil go through geographic bottlenecks that could be weaponized against them in the event of military conflict. Coal, fissile materials, and sunlight are the alternatives they have access to, so they're going for all of those.

With some luck, the net effect will be fewer greenhouse gases than keeping themselves oil-dependent, though that isn't necessarily the, or even a, goal. If it happens, it'll be as a side effect.