Satoshi style PoW algorithms are intended to waste as much energy as possible.

PoW mining just raises the capital cost to control the network without ever improving the speed or functionality. It's a system that increases the waste as time progresses.

I wonder about some tasks that people already do for charity with their computers...like protein folding, finding super huge prime numbers. I don't know enough about the algorithms involved though to assert they satisfy the POW requirements. But some infrastructure already exists to distribute these problems.