I think both metrics have their value. g/kwh gives you nice overview at how clean the energy is, and there is value in optimising that figure. The problem with

I think both metrics have their value. g/kwh gives you nice overview at how clean the energy is, and there is value in optimising that figure. The problem with measuring CO2 per person is that it is heavily influenced by the wealth level of the country's population. Poor counties have very low CO2 emissions, but people in wealthy countries wouldn't want to trade their living standards for those of a poor country. That would arguably be worse than climate change in the first place. So optimising for CO2 g/kwh allows us to reduce our emissions without reducing our quality of living. Which is great. That being said, I agree that running escalators at night is a terrible waste of energy.