The reality is that we are probably stuck with energy-guzzling cryptocurrencies, at least for a while. In the meantime, maybe true believers would be wise to invest their digital coins in renewable electricity sources.

The one in the best position to supplant proof of work is called “proof of stake.” Whereas proof of work rewards participants for spending computational resources, blockchains that use proof of stake would select validators based in part on the size of their respective monetary deposits—their stake. This would be massively more energy efficient, but the concept is still unproven at a large scale and has a number of kinks that need working out.