There is a lot of bad math and bad logic on the topic of energy being cast about these days.
The example of sloppy thinking which irks me the most is the simple use of miles per gallon as the final arbiter on energy efficiency, and thus, in the minds of many, moral cleanliness.
In my estimation, an SUV which gets 15 miles per gallon but regularly carries five people and all their gear is about five times as efficient as a Porsche 911 which gets 15 miles to the gallon and regularly carries one person and maybe a cellphone. When people rail about wasted energy, why do they talk about SUV's instead of sports cars?
As I drove my family home from a short vacation in Washington, DC, today, all five of us in the car, stuff packed to the rafters, I realized that the more appropriate measure for energy efficiency should be person-miles-per-gallon.
Under that standard, we were cruising along at about 80 PMPGs. In order to commute alone as effectively, our neighborly Prius driver would have to pitch his prized hybrid in favor of a motorcycle. I try to take it one step further by riding a bicycle to and from work as much as I can.
Full Disclosure: until very recently, I also regularly drove a Porsche. Please realize, I am not moralizing here, only pointing out faulty logic.