Tech check: Why hybrid car Eco-nomics don't add up

Hybrid cars are sexy. They are the most energy efficient automobiles when measured in miles per gallon, and they make a social statement about fighting global warming. They are the anti-Hummer. But are they the best way to invest your dollars if you truly want to reduce your carbon impact on global warming? Not necessarily. Just do the math.

I was speaking with Eric Carlson, executive director at this week about Dell's program that allows PC buyers the option to purchase carbon offsets when the this topic came up. The nonprofit acts as an intermediary between customers who want to buy carbon offsets and reforestation programs that plant trees that remove carbon dioxide(a total of 2,000 lbs per tree) from the atmosphere. (To plant the trees, works with Environmental Resource Trust and Rainforest Alliance. Third-party verifiers audit the programs.) Buying carbon offsets with an energy efficient PC is one way to compensate for the carbon emissions directly related to the PC's consumption of electricity during its useful life.

That was all fine and good. But then, somehow, we got to talking about hybrid cars.

Consider this scenario: You buy a hybrid and pay the premium - somewhere around $3,500 to $5,000 for a Honda Accord hybrid, according to my local dealer. Now let's assume for a moment that your hybrid gets 50 mpg. I buy a Civic for less money that gets 38 mpg. We both drive 12,000 miles per year. At the end of that year I have burned 316 gallons. You used 240. Every gallon of gasoline consumed generates about 20 lbs of CO2, among other pollutants. So I'm putting about 1,520 more lbs of CO2 into the atmosphere than you are. The hybrid wins.

But wait. I saved thousands of dollars by not buying a hybrid. Says Carlson, "You can offset those extra emissions for $3.80 a year [in carbon credits]."

It gets better. If you bought the Honda Accord hybrid you paid at least $23,000. You can't get a base model Accord in a hybrid - the hybrid version fits between the more upscale EX/LX models - and you pay that $3,500 to $5,000 premium over a comparably equipped non-hybrid version of the car. Wanting to do my part for the environment, I make a sacrifice and buy a smaller Civic for $15,000 - spending $8,000 less.

For 10 bucks you can buy about 650 lbs of carbon offsets through organizations such as EFI. also sells them, of course. If I invest my purchase savings in carbon credits I can start my own small forest. On the low end, my $3,500 savings from not purchasing a hybrid buys 227,500 lbs of CO2 offsets. Since each tree consumes about 2,000 lbs of C02, I just bought 113 trees. I bought a Civic and saved $8,000, so I can buy 520,000 lbs of offsets, which adds about 260 trees to the planet. Or I could just by a carbon offset that covers my car's lifetime emissions for about 20 bucks.

The Accord hybrid emits 1,520 fewer lbs of CO2 per year than my Civic. But by investing the difference I've recovered all of that - and taken nearly a half million more pounds out of the environment.

Mind you, all of this isn't entirely apples to apples. The trees remove one ton of CO2 over a 70 year lifespan, while the auto's lifespan is probably 7-10 years. But it does come out eventually. And the forest continues on as a sustainable resource - one that's been decimated over the past 150 years and whose decline is responsible for about 20% of global warming, according to Carlson.

The carbon math also doesn't take into account the fact that manufacturing a hybrid also produces a bigger carbon footprint due to the fact that it requires the manufacture of redundant power plants - a gas tank/engine and a battery bank/motor. All of those subcomponents had to be manufactured and shipped to the final assembly plant.

Hybrids are sexy and make a statement, but require no real sacrifice. Sure, they cost more per mile to run than an economy car because people pay more for them up front. But so do Hummers. People are paying the premium for the cache of a hybrid. It's all about brand and status (If you don't believe it look at how hot Prius sales haven't trickled down to more pedestrian hybrid models introduced by Ford and others). People buy hybrids because they're upscale and make a very public statement about being eco-friendly, just as Hummer owners make their own statement to the tree huggers (A few years ago I saw a Hummer on the highway with two bumper stickers: One of the American flag and the other said "Nuke Iraq."). A hybrid is a feel-good investment.

As an eco-investment, however, I'd rather see the forest for the trees. Another way to save the environment is to live smaller. Buy the most energy efficient car you can and invest the savings in energy conservation, renewable energy or carbon offsets.

Doesn't that make more sense than buying a hybrid?

Copyright © 2007 IDG Communications, Inc.

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