[Marazan]

No, the amount of energy needed will always be enormous as their is a direct linkage between the value of bitcoin and the amount of energy required to secure the network.

Otherwise there will be a point where it is cost effective to attack the network.

Bitcoin is designed to be wasteful.

[EdSharkey]

I guess I was asking for a hypothetical, new crypto coin. Does proof-of-work have to be costly compute-wise in order to be proof-of-worky?

[lordnacho]

Yes. Think about what it is.

"I'm working on these hashes. You know I'm not taking a shortcut, because there's not yet a known way to do that with this secure hash. And because you know I'm doing the work, you should reward me with some coins."

Alternatives have been considered, like proof-of-stake.