Ethereum as a non-mineable coin is a green coin because it saves a lot of power and hardware expenses, mining hardware had an obsolescence cycle of six month which in turn dumping another electronic hardware to the ground that contributes hazards to environment and also taking a lot of waste of energy source from mining is not a good idea why not redistribute the power source to other community like street lighting. if no miners in an Ethereum ecosystem it can save a lot of megawatts of electricity, Mr. Buterin was a good visionary for his Ethereum he saves the mother earth.
I think you don't understand PoW very well, buddy. There is not such a thing as waste of electricity. It's actually being used to make the network safe, and prevent attacks.
He does, he is saying POS does the same thing which is processing blocks and keeping the network secure but without using all the power from POW