I think that as Bitcoin get’s more traction, it may even accellerate the production and adoption for alternative energy sources world wide, since the value of Bitcoin will give more and more people an incentive to start mining.

With that mining could becme decentralised again, the biggest issue is the 51% attack and decision making into the future of Bitcoin. I think they are implementing a proposal to make the 51% attack less likely by allowing smaller miners to use individual settings?
The problem is also that mining is a business, and businesses tend to conglomerate, so centralization is part of the concept of mining, this is not something that can be stopped imo.
Unless you change the proof of work protocol... to something that remains decentralised.