07.01.08

Should I buy a hybrid?

Posted in Energy, Society at 16:58 by RjZ

Car sales are down in the United States. I don’t think we should be surprised. If you’re only a few years into payments on your SUV it’s unlikely that, with the extra pinch of gas prices, you have enough extra money just lying around to simply get rid of the car you’ve got and get another one. You could go a little deeper in debt, but then credit’s a little tighter these days.

Suppose you’ve got the money and you’re really more interested in saving the environment. The question is, should you trade in that guzzler for a hybrid? Hybrids burn much less gas and produce fewer green house gases (GHGs), right?

Imagine you’ve got another 10 years at 12,000 miles per year on your car. I’m guessing that’d be around 200,000 miles, give or take, which, with some care, I think most cars from the last few decades will pull off. Say you’re getting 21 miles per gallon. A hybrid will get around 46. So that’s 25 miles per gallon for 120,000 miles or a savings of 4,800 gallons of gas! Not bad, at $4, that’s $19,200 over the next ten years. This is great news, from a cost standpoint. The five year cost of ownership of a Prius is only around double that, so, with today’s prices, it’s not such a bad deal!

The question I am asking though, is should you trade in your still working car for the environment’s sake? A gallon of gas creates about 20 lbs of CO2, so buying that Prius will save the environment at least 96,000 lbs of CO2. Except, how much CO2 and other GHGs are produced in the manufacture of a hybrid? Alas, I couldn’t find this data quickly on the web, but I’ll hazard a guess. A Prius weighs almost 4000 lbs. It’s a pretty fair assumption that producing all those machined parts, mining and smelting all the metal for the body, engine, battery, suspension etc., four tires, foam and carpet filled interior, and not least, transporting all the various pieces half way around the world, probably works out to quite a bit more than another 90,000 lbs of CO2. Without doing the math, I wouldn’t be surprised at 900,000 lbs of GHGs. Anyone have a real reference here? A couple of papers on the web were available at charge.

If it’s time to buy a new car, consider a hybrid, I am sure it’ll help. Just don’t buy something you really don’t need just to spare the environment. Reduce first, as the saying goes: reduce, reuse, recycle. I’ll be driving my 130,000 mile car for a few more years, even if there are cleaner cars out there.

Update 9 July 2008:
Slate’s Green Lantern takes the opposite view to my point using BTU data. Honestly, I am not really in a position to dispute this much but the calculation there doesn’t take into account the waste of producing more cars, more frequently than necessary (although he does touch upon this.) Worse, we have little knowledge of just how much of a Prius is reusable or recyclable (let alone reused or recycled). Finally by stretching the use of the car out to 11.5 years, a good idea, but certainly not usually what happens, the scales tip in favor of the Prius. Cost of ownership and cost to the environment continue to drop the longer something is used. That, after all, is the point I concluded with above: reduce, reuse, recycle–in that order!

Thanks to one of my faithful readers for the tip. I am interested in other data on this subject if folks come up with any.

3 Comments »

  1. dingle said,

    July 2, 2008 at 16:16

    It’s a good point, I’d guess you’d never recoup the manufacturing footprint if you changed early (unless you’re driving a Hummer?), you should probably drive your current car into the ground before you change, anyway, the longer you wait the more efficient new cars will become, meaning you’ll save more. I guess the economics of running a thirsty car with the rapdily increasing oil prices might push your decision sooner though.

    I’m interested in how efficient things like wind power generators are, do they ever recoup their manufacturing footprint in their lifetime?

  2. RjZ said,

    July 2, 2008 at 16:33

    Great idea! I don’t have much on lifecycle data (heck, I couldn’t even find it for the Prius) but this should be a quite reasonable thing to guess.

  3. Traveling Hypothesis » Coal-fired cars are here! said,

    March 22, 2011 at 9:10

    [...] I mentioned in an earlier post, it’s best for the environment to drive your car into the ground. If your old car is coming [...]

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