I slightly dislike(I know, I can be petty) those Twitter people who seems to think that Bitcoin is the answer to literally whatever news-trending problem there is. But "wasted" renewable energy is one good use-case of Bitcoin mining. They contribute to the network, and at the same time they get value in exchange for the supposedly wasted energy. Win-win!
Plus the energy providers help distribute the Bitcoins to the users, through the miners. Energy providers that power the Bitcoin network are becoming like quasi-central banks, without themselves understanding their role. They are going in it because of the incentive structure. Satoshi is a Genius.