@aliashraf
I think you are overcomplicating things. PoW is useful because it allows for trustless consensus. PoS needs some kind of "social network" to function, in order to know what the "real" chain is.

As for energy consumption, I don't see it as a problem. What I see as a problem is centralized energy consumption. Without large forces of centralization I don't think it would be possible to damage the environment in a significant way, and maybe even total (global) energy consumption would decrease. Also, merge mining would help to keep energy consumption for efficient, as you can mine multiple blockchains in the same time for the same energy cost.