Wednesday, July 16, 2008

New hybrid cars and global warming

I just saw an interesting statistic in "Design News" (engineering magazine) that claimed that making a pound of steel or plastic required the energy input of about two pounds of oil, while the production of a pound of aluminium requires the energy input of about five pounds of oil. Now consider that in light of the prospect of purchasing a 3000 lb Toyota Prius to "save energy and reduce carbon dioxide emissons."

Now let's be fair, here; making the Prius requires mostly coal for energy, not oil, so there is probably a net reduction in petroleum usage after one reduces gasoline use by only a few hundred gallons--about a year or so of use. However, from a carbon emissions point of view, you're talking not about 6000 lbs of oil, but rather about 10000 pounds of coal. You only "break even" from a carbon emissions standpoint after you save about 1500 gallons of gasoline.

So if you trade in an ordinary compact car (Cobalt, Civic, Corolla, etc..) for a Prius, you can expect to balance the carbon impact of your new ride after only about 150,000 miles--really the entire useful life of the vehicle. There are better ways to reduce carbon emissions.

Got my first ride in a hybrid (Camry) this morning, by the way. Eerily quiet at times, and not quite enough headroom for me, but otherwise a reasonably nice car. Since I'd ridden my bike to a men's prayer breakfast today, I also got to tell the owner that he was destroying the environment in his gas guzzler. :^)

4 comments:

jroosh said...

Oh and by the way, when you are done with the Prius, what happens to the heavy metals in the battery?

I wonder how much better you would come out if you bought a four-door Honda civic with a traditional gasoline four cylinder engine and invested the difference, say three to five grand, in even a conservative portfolio?

Bike Bubba said...

Not sure. I've wondered the same about the battery, and I'm keeping my money for a new car until I need one.

The numbers I've run indicate that the Prius and other hybrids might break even with ordinary driving and a 6-10% cost of money when gas gets to about $10/gallon, or at current prices at about 60,000 miles per year--which brings the additional question of replacement cost, of course.

Gabrielle Eden said...

My cousin says that disposing of the battery is very harmful to the environment. And the battery has to be replaced at 80,000 miles for about $5,000.00

Shawn said...

jroosh...in line with your comment, and BB's hesitations--

in an econtalk podcast with mike munger, chair of the polisci department at Duke (and libertarian candidate for governor of NC, in interesting but unrelated news), Munger related a story from a Duke department head meeting, where everyone 'went around the table and related what car they drove' (strange, eh?):

Virtually everyone drove a prius or some other hybrid (mike drives a 1997 dodge caravan...great for hauling "baseball stuff"). Next to him was the chair of the chemistry department, who said (paraphrased) "you know...on net, especially when you consider the disposal of the batteries, a prius is at best on par with a comparably sized IC engine vehicle (a corolla or a civic), and likely worse for the environment...but I still drive a prius, because that's what you have to drive to be a faculty at duke."

I believe that's in the econtalk recycling podcast...the earlier of the two with munger on that topic.