Monday, March 03, 2008

Greenhous gases - doing the math

Three times this winter I've turned the crank on my 1994 Ford Escort and had it not start right up. Admittedly once was a dead battery and once was a defective battery but still, I'm considering the reality that one of these days I'll have to overcome my natural lethargy actually replace the thing....so, I've been reading up on new cars...and carbon footprints...and have been trying to work out to what extent getting a hybrid is an effective way to save the planet and to what extent it's just sort of cool.

Somewhat surprisingly, the nicest carbon-footprint calculator I found was at the EPA. According to them, replacing both my cars with something that had better than double the gas mileage would save about 2300 lbs of CO2/year - but I'd save more with a either newer furnace, or with new windows for my house. I'm probably atypical here, as together Susan and I drive about 100 miles a week, but still, I was pretty surprised.

Another data-point came up today in Low-tech Magazine: according to them, at least, the carbon cost of manufacturing the 8m^2 of solar panels needed to power a house is between 60,000 and 940,000 kgs of C02 - and according to the EPA this is the same carbon cost as between 20 and, um, 300+? years of electricity use for an average family of 4. Of course, this could be way off base, but it seems to me that we need to set up either some sort of marketplace mechanisms to allocate CO2 savings efficiently - just following the trends may not get us there.

3 comments:

amberman said...

Does the calculator fully consider the impact of REPLACING an existing automobile? What will be the downstream impact of the existing car? I would guess that unless you have an EXTREMELY inefficient car, or drive very long distances, keeping the old card is going to have less impact than replacing it, no matter how efficient the new one is.

William Cohen said...

No, it doesn't consider the replacement cost. Really you need to know the carbon cost of manufacturing the new car (and the old car) and figure out what the manufactoring CO2 cost is amortized over the lifespan. And of course driving cars longer would reduce the amortized cost. I'd love to see a calculator that took this into account, but I've never seen one.

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