This news from Kumamoto, however, shows that in some cases cryptocurrency can facilitate a potentially greener future. Many renewable energy sources such as solar, wind, hydro and geothermal are located in remote places away from consumers. They are also uneven in their yields compared to traditional and more polluting sources. By using excess capacity when it is available to mine, the crypto economy is making remote renewable energy more affordable and profitable and thus much more likely to be tapped into.

https://news.bitcoin.com/japanese-electricity-company-uses-excess-solar-power-crypto-mining/