I say! What does it all mean? I must admit the ruthlessly anti-CO2 premise appeals to me. These sound like some interesting if incendiary points. Lets scratch beneath the surface:
Keep your SUV. After a silly comparison between a Hummer and a Prius, they admit (without any trace of embarassment) that SUV's are indeed bad for the environment. But their real point is to highlight the under-appreciated environmental cost of manufacturing a Toyota Prius. Making the nickel battery is carbon intensive. When a new Prius (45 mpg) is compared head to head against a 10 year old Toyota Tercel (35 mpg). Excluding the manufacture of the Tercel (after all it is used - grrr), we learn it would take the Prius 100,000 miles to break even. Their recommendation is to buy a used car with reasonable mileage. How inspiring. I wonder where all these used cars are going to come from that we are all about to buy. Can we get Toyota to make some more 1998 Tercels? But wait, then it wouldn't be used, would it?
It is useful to know about the production issue with the Prius battery. While 100,000 is a nice round number, lets turn it into something more relevant. How many miles of Prius driving is the battery equivalent to? Here we go:
Let G be the equivalent gallons of gas and M be the equivalent miles for making the battery. Now we balance the Prius gas (real + equivalent) against the Celica gas:
100,000 miles / 45mpg + G = 100,000 miles / 35mpg
which yields G = 635 equivalent gallons and thus M = 635 * 45 which is a bit less than 30,000 equivalent miles, or about 2 years of driving (or six months in a Hummer).
It is a little disheartening to be sure. But for those Prius owners out there, take heart - the success of the Prius has stimulated investment in a burgeoning green engine industry. So keep your Prius, but don't buy a second one until Toyota comes out with an improvement.
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Ah, finally I have found the answer to a burning question: What is the CO2 footprint for the production of a normal car or a Hummer?
Thanks to a study by the Argonne National Lab, we have some idea. Here is a nice summary.
http://www.triplepundit.com/pages/askpablo-time-to-get-a-new-car-002538.php
The key metric is energy per pound of vehicle, where energy is a good proxy for CO2. For traditional combustion engine vehicles, this number is 31,362 btu/lb and for a hybrid it is a bit more at 38,650 btu/lb or 23% more. This means that the manufacturing footprint of a Hummer is substantially larger than the humble Prius.
Clearly SUV's are ridiculous so let's have a fair fight: a regular Civic versus a hybrid Civic. We have 24 mpg city / 36 mpg highway versus 40 mpg city / 45 mpg highway. How many months or years does it take for the hybrid to catch up? Let's assume the driver is doing 50% city and 50% highway. The weight is 2875 pounds.
Hybrid = 2875*38,650 + (113,500/42.5mpg)*miles
Regular= 2875*31,362 + (113,500/30mpg)*miles
And the number of miles is 18,830, which is a little more than 1 year of driving. The hybrid is better.
Oh yes, and lets not forget the greenest of options (by the obtuse logic of Wired at least): Don't buy a used Celica, buy a used Prius!!
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