Chewing gum for the brain. They are looking at it that all energy production is harmful and which one is least harmful. If they picked cars or something else they would come to the same decision. For example, which method of accessing the internet is best? How many carsongerics are made in the production of a pc, mac, tablet, phone, chromebook, etc?
Im sure power will follow gas, as it costs more, people will use less. I mean it as third world countries and part of the US resorts to rolling black outs to "regulate" load on the system.