[MetroMPG]

The company that provides renewable electricity in Ontario (Bullfrog Power) says in its promo material that many of the customers who switch to their more expensive electrons don't end up paying more on a monthly basis because they find savings through increased efficiency & conservation.

It makes sense - the type of person who would opt for renewable power (at least the early adopter) is probably also interested in efficiency and is more aware of the impact of their behaviour on consumption.