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!

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.

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.

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.

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.

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.