Reflecting on my earlier post here, I decided to do some quick research on criticisms of the report that claimed that the “all in” or “dust to dust” energy cost of a Hummer was less than a Prius. Here’s some of what I found:
1. An interview with the President of the company that conducted the report said that the report assumed that trucks and SUVs would have much longer lifetimes than a Prius. In particular: “The study uses expected lifetime mileage of the vehicles. Hybrids are only expected to live for 100,000 miles, but trucks are expected to live for 250,000 miles. This influences the $/mile significantly. If a hybrid could be driven 250,000 miles, it would be much more favorable compared to other vehicles.” This may be greatly overstated; according to one site, using National Highway Traffic Safety Administration estimates for 2001, the difference in longevity between cars and trucks was only 18% (152,000 miles for cars, 180,000 miles for trucks).
2. As another site notes, because hybrids are a new technology, they have more energy costs associated with the more extensive recent research and development necessary to create them. The report “fails to take into account the comparative R&D costs already sunk in the development of the internal combustion engine, years ago. So add the life cycle of the technology in question itself to the total tally and perhaps we would get a better picture of realistic ‘energy costs.’ Problem is, you can’t. The internal combustion engine’s life cycle isn’t over yet and the hybrid life cycle just begun. Hence the defining boundaries of the “dust to dust” concept itself remain ambiguous enough to render this approach somewhat problematic.“
3. The data and assumptions underlying the report were not originally released. They now are apparently available here. It will be interesting to see the extent to which they are challenged.
Categories: Environment, Science