Rather than repeat what others have written, I would like to point out the problem with "carbon footprint".

The "carbon footprint" concept was invented as a way to get consumers to pressure the greenhouse gas producers to reduce their carbon emissions. Now the concept seems to be shifting that responsibility away from the actual culprits.

It is up to the power generators to reduce the amount of carbon that they burn, and not the users of their electricity. If power generators burned no carbon, then users would have no carbon footprint, regardless of how much electricity they use.