The structure of your comment suggests you don't grasp the fundamental point of proof-of-work, which is precisely to prove that a certain amount of (physical) r

The structure of your comment suggests you don't grasp the fundamental point of proof-of-work, which is precisely to prove that a certain amount of (physical) resources were expended. > Is there any reason a cryptocurrency can’t be made that uses very little energy? As far as proof-of-work is concerned, if you don't use enough energy, you are vulnerable to 51% attacks. As far as other schemes (e.g. proof-of-stake) are concerned - none of them have the same desirable security properties as PoW.