The amount of energy BTC mining consumes is insane at this point and will definitely be its biggest flaw for a while. There are figures that mining BTC currently consumes more power than 159 countries around the world. There is no way that figures like that are sustainable unless BTC miners have some plan to move to greener forms of mining or more power efficient mining farms or BTC as a whole has a plan to switch to another consensus algorithm other than Proof of Work but that is hypothetical. This is one of factors that makes people believe that BTC has an expiration date.



https://powercompare.co.uk/bitcoin/