According to Wired Magazine, building a Toyota Prius consumes 113 million British Thermal Units (BTU), while a gallon of gas contains about 113,000 BTU. The 2008 Prius can go 48 miles per gallon (on highways).
A 1998 Toyota Tercel, on the other hand, does 35 mpg and, since it is used, the carbon cost of construction has already been paid.
This would mean that it would take about 129,230 miles of driving before the 2008 Prius surpasses the 1998 Tercel in eco-friendliness.
Incidentally this calculation can be made for any used car you wish to buy. You can find our worksheet that does exactly that right here.
I have read a similar report about transporting paper bags as opposed to plastic. Paper bags take up more space in a truck, and therefore require more trucks to carry the same amount. At what point do the two cancel each other, I do not know.
so…does this mean a hybrid vehicle isn’t necessarily the most cost effective?
What happens when the energy that goes into the Prius’ production does not derive solely from carbon emitting sources such as Nuclear power? If anything, shouldn’t the calculations for its carbon footprint be discounted by an estimated percentage that the power ‘grid’ derives its energy from renewable sources?
Phoebe: Yes, although for costs you could compare a hybrid to any new car as well. A hybrid will cost more to buy, but less per mile traveled. That is not the point of the article, however.
Jason: If the energy came from nuclear power I imagine it would consume fewer BTU. I’m an advocate of Nuclear power in general, but as far as I know, none is used to make a Prius. If it is, then that is already factored in the 113 million BTU.
Sorry, but I have to assert myself here…
What I was getting at was how the avg carbon footprint would change depending on the makeup of the energy sources from which the Prius factory derives its electricity.
For example, if the plant was located in France, it would have a smaller carbon footprint than if it were made in say, China – because France is predominantly powered by nuclear energy and China is heavy on the coal (much like the US).
Specifically to the US regions, if the plant was near a wind farm, or a major hydro-electric dam, then they could also potentially claim that their carbon footprint is minimal.
Now, if in the original calculations, the statisticians accounted for the differences in energy production makeup in a given area, then I would be more understanding of the claim laid before us. Until then, I’ll simply say GO Prius! (or any other, more efficient/cost effective method of transportation).
btw: British Thermal Units are a measure of energy and nuclear power is a method of producing energy – not a consumer of it.
Wait, this discussion is spiraling into incoherency. First, you should not compare a new Prius to a used anything. If so, you can compare the Prius to horses – used, clapped-out horses. (Which, BTW, have a high carbon footprint for the work they produce.)
And the sources of the energy used in making the Prius, or any other product, is a separate discussion from the carbon produced by using the product. A Prius or a horse produces a certain amount of carbon, whether it was manufactured using nuclear energy or by a mommy horse and daddy horse.
I’ll have to humbly disagree with you on this one, Senectus.
Ocean is basically making the observation that, to find the least costly way to transport yourself by car (in terms of energy consumption), it is best to use that which has already been created instead of producing something anew and then using it. That is, unless, you plan to drive the Prius for x amount of miles because then the differences in efficiency (mpg) makes it less costly than the older, used product.
I, on the other hand, had incorrectly argued the claim by equating carbon footprints with energy production. Though, I must say that his second statement confuses the argument.
I think what you are all failing to take into account is the fact that a used Toyota Tercel might cost fewer BTU to produce (because it is already produced), that number is not zero. Every repair made to the Tercel to keep it in working condition depends on new parts, which require energy to manufacture.
Sure, the Tercel will use less energy than the Prius, but not as much less as represented in this article. In addition, at some point the Tercel will stop working completely, requiring a large overhaul (engine, transmission) that would likely bring the Tercel into Prius range in terms of manufacturing energy.
Jim, that’s true. I did over-generalize. A more accurate calculation would take into account the average carbon cost per average repair per year of Tercel usage. A similar calculation would have to be done for the Prius (at least for the first 130,000 odd miles).
And yes, the average life-span (or total mileage) of a Tercel should be taken into account as well. Once it stops working and a new car is needed all bets are off.
The end result would, most probably, bring the mileage-to-ecofriendliness-equilibrium point down. I cannot say by how much, but any ideas on how to obtain these average numbers would be welcomed, and I’d be glad to update the worksheet.
Thanks for pointing these out!