Monday, June 9, 2008

TANSTAAFL

I heard this on the radio this morning.

I direct your attention to this fragment in particular:

...you can creep along just using the electric motor which is great, you have zero emissions...

Well, no, if you creep along just using the electric motor, eventually you will run out and stop moving. From my vague understanding of how these things work, you need to run the gasoline engine to charge up the batteries.

I worry how much these sort of fuel-efficient vehicles are affected by what we might call the 'low-calorie pretzel' effect. The diet snack food has fewer calories, so you eat more of it. You are already 'doing the right thing' by driving your gee-whiz environment-friendly car, so you take it on trips where a person with a vehicle which is more expensive to run might walk, bike, or use public transport to save money...

1 comment:

Marco said...

OOhh. I know the answer to this one! It is called the "Rebound" effect, where a percentage of the money saved on lower energy costs is spent on things that use energy. Various studies have shown this percentage to be substantial and extremely variable, at around 20 to 40% of the energy saved being rebounded as a very rough estimate. Controlling energy demand through taxation is not a lot more efficient, because of the efficiency of the government to spend this money on energy intensive vote-winning expenditure.