energy inputs

this is the kind of thing that physicists are always getting frustrated about:

CNW's findings indicate that a hybrid consumes more energy overall than a comparable conventionally powered model. It judged showed that the Honda Accord Hybrid rang up an Energy Costs Per Mile of $3.29, while a gas-powered Accord was significantly cheaper at $2.18/mile. The study concludes that the average of all 2005 U.S. market vehicles was $2.28/mile.

The reasoning goes that hybrids use up more energy to manufacture, as well as consume more resources in terms of the assembly (and eventual disposal) of things like batteries and motors. By CNW's reckoning, the intrinsically lower complexity of, say, a Hummer H3 ($1.949/mile) actually results in lower total energy usage than any hybrid currently on the market, and even a standard Honda Civic ($2.42).

While I am in no position to evaluate the methodology, I think that it is critical to assess overall net energy rather than simply energy at one stage in any supposed "green" initiative.

Many environmentalists seem to assume that hybrid vehicles magically appear - generated by fairy dust and Mother Gaia - and then at the end of their lifespan will simply be re-absorbed into the ecosystem.

I think that hybrid technology is important and that buying hybrids is a good idea because it will help reduce manufactring costs and increase economies of scale. After all, today's gasoline engine is orders of magnitude more efficient than the one in the Model T.

However, buying a hybrid is definitely a poor choice of you are out to save money. I'll leave the simple math as an excercise for the reader - just compare a 25 mpg vs a 50 mpg fuel economy, with the latter costing an additional $5000, and see how many years it takes to break even (with gasoline at $2.50 a gallon and driving 15,000 miles a year).

And as for the green aspects of hybrids, regardless of the specific numbers above, it is quite reasonable to assume that the overall energy cost of production is substantially higher than a conventional vehicle. Denying this fairly obvious fact is detrimental to credibility on green issues.

The irght long term solution for automobiles is to go fully electric. Hybrids provide an easy vector for improvement of battery technology with immediate fiscal incentive for the automakers to drop the big R&D bucks. But no one driving a hybrid has any real reason to feel particularly green.

I plan on considering a hybrid next, myself.

(via Brian)

1 comment:

Andrew said...

Caveat: I am physics retarded.

I would think that the thing that makes a hybrid useful is that even though it may require somewhat more energy, a lot of that energy is at the front and back ends. If the question is not so much scarcity of energy as scarcity of oil, then they still make a great deal of sense. After all, an assembly (or disposal) plant is much more suited to using non-oil energy (be it coal, wind, solar, hydroelectric, whatever) and thus may result in a hybrid saving on oil.

The other thing about a hybrid that I find attractive is that both my wife and I really like to drive. In particular, I quite enjoy long road trips (in 1999, I drove from Angleton, TX to Alaska and back), and so having a hybrid makes sense in that case, as it means less gass used and less damage to the planet as a whole.

All of which is why I am pretty sure that if I manage to wrangle a tenure-track job once I get my dissertation, H. and I are probably going to get a hybrid.