Did You Buy Carbon Offsets for that Prius?

The good folks at Wired.com have an article “Don’t Buy That New Prius! Test-Drive a Used Car Instead” that discusses how to evaluate the eco-friendlieness of cars. And surprise! That Prius people are so sanctimonious about turns out to be not as green as many cars out there.

I’d heard on The Dave Ramsey show that new cars are not necessarily a good deal from an economics point of view based on gas mileage, cost of gas, and the premium people pay for hybrids. But this is the first time I’d seen comparisons done strictly on energy consumed in manufacturing and operating the car.

According to the Wired article:

” Making a Prius consumes 113 million BTUs, according to sustainability engineer Pablo Päster. A single gallon of gas contains about 113,000 Btus, so Toyota’s green wonder guzzles the equivalent of 1,000 gallons before it clocks its first mile. A used car, on the other hand, starts with a significant advantage: The first owner has already paid off its carbon debt. Buy a decade-old Toyota Tercel, which gets a respectable 35 mpg, and the Prius will have to drive 100,000 miles to catch up.”

I can’t help but note the apples-to-oranges comparison they are making.  On the Prius side, they include both the energy in manufacturing and the energy consumerd. On the Tercel side, they say that the original owner has already paid for the energy so they claim that you don’t have to include it on the Tercel side of the sreadsheet, when you are buying the car used.. So it’s not quite a fair comparison.

But if you buy a used Tercel, you are eliminating the need to manufacture a new car. And from this point of view, the calculations are entirely correct. By far the greenest approach to cars is to reuse an existing car. In other words, the greenest way to get a set of wheels is to buy a used car to prevent the manufacturing of a new one. I can’t wait for eco-friendly signs to start popping up at used car lots all over the country.

Your mileage may vary of course. But I find it difficult to argue with the basic logic.  The good folks at The Dumb Agent blog have created a spreadsheet you can use to do your own comparisons.

photo credit File:Toyota Prius III 20090710 front.JPG