Interesting - while the main point of the article is correct (buying a used car is more environmentally friendly than forcing another new one to be built, adding yet another car to the planet), you may want to also include the approximate energy required to produce vehicles other than the Prius. Because after all, without context the 113 million BTU number is completely meaningless. By the way, the site I got this from is one of the sources for the article linked above.
Source:
http://www.triplepundit.com/pages/askpablo-time-to-get-a-new-car-002538.php
Also, the environmental impact in this discussion so far seems to be focused mainly on energy consumption. At some point, an older car will pollute far more smog-forming emissions (unburned hydrocarbons, etc.) than will a newer car. Don't believe me? Stand behind a 2008 Malibu with the engine running and you'll barely smell anything. Do the same with a 1988 Grand Am and tell me how it smells.
Hmmmm , where are the transportation energy costs to bring the Prius here ???
Thats more important than most realize as we now know that
measured green house and pollution effects from heavy seaborne transport were previously understated by a factor of 5-7.
Again, since the used vehicle is already here its factor is zero - regardless of origination.
Also, the energy costs here for the Prius ( I think - not sure - check later ), - do not include the carbon/energy foot print for its rather unique pre assembly 'transport' requirements.
Where are the energy costs for either one - for recycling ???
Actually the 'energy costs' of other new vehicles are completely irrelevant - its used cars versus the Prius.
And as to pollution costs or footprints the article is limited to a carbon footprint comparison .
Having said that, yes I agree total environmental impact is an important part of the overall equation - one which only buttresses the argument made here against the Prius as the only green solution and calls into question if the Prius is 'really ' 'green' at all.
If you try and account for the total environmental impact of a Prius from cradle to grave no matter how you do it, its not even mid pack - amongst new and, obviously, is an even bigger loser against used.
As to standing behind a vehicle to sample the pipe and draw a conclusion.............. well, there are better ways to do that.
Other tailpipe emissions have to be measured very specifically to draw comparison values.
Since we're comparing used cars ...... and all kinds of drive cycles for both new and used.................. well good luck.
Also worth noting, its common now when comparing different emissions numbers to skew the argument to the point of absurdity by ignoring the total, operational count and over focus on next to useless rate remaining theoretical comparisons.
As the UK is finding out, you also need for obvious reasons real world FE numbers.
Its somewhat of an exercise in futility anyway.
Based on the molecule/compound 'type' count, most are not measured anyway.
Finally Argonne Lab's GREET model has been very controversial - no surprise, it appears somewhat biased against some and biased for others - like battery hybrid PT systems.
A revised version was recently released.