Hybrids Greenest SUVs, Diesels Tank in Ratings

The American Council for an Energy-Efficient Economy (ACEEE) released its annual Green Book guide to car buying. The 2008 model year saw little change over the previous year with the exception of Smart Fortwo Convertible near the top of the ratings and the new hybrid large SUVs being the best of the beasts.

As for the last five years, the Honda natural gas-powered Civic GX was ranked as the greenest vehicle, followed by the Toyota Prius and Honda Civic Hybrid. The new Smart Fortwo Convertible jumped into the fourth spot, proving that the diminutive car was built to be as easy on the environment as it is to park. Sales of the Smart Fortwo have been brisk, which makes you wonder why Daimler waited so long to bring the car to the U.S. when there was obvious demand. The Toyota Yaris rounded out the top five.

Two hybrid large SUVs - the Chevy Tahoe Hybrid and GMC Yukon Hybrid debuted and were rated as the best of the worst class of vehicles. While the big vehicles have come under criticism as not being worthy of the "hybrid" mantle because of their relatively low MPG compared to passenger vehicles, ACEEE correctly points out that "hybridizing" these vehicles will have a greater impact on emissions and fossil fuel consumption than adding electric drive trains to passenger sedans.

 In fact, bumping up the low end of the efficiency spectrum is the quickest way to save fuel and reduce CO2 emissions: raising the fuel economy of, say, a Yukon Denali from 14 to 16 miles per gallon would save over 100 gallons per year for the typical driver and eliminate 1.3 tons of CO2 emissions, while achieving the same savings through improvements to a 42 mile-per-gallon Civic Hybrid would require a 25 mpg boost, to 67 mpg.

The reality is people will continue to buy these larger vehicles to tow boats or to drive in the snow. Spending a few thousands dollars to add a few MPG makes financial sense for SUV owners as well as doing better by the planet.

ACEEE continues to take a hard line on diesels because despite fuel economy that can be on par with hybrids, the pollutants emitted are viewed as much worse than comparable gasoline vehicles.  The four diesel vehicles listed below along with the gasoline Bugatti Veyron all were viewed as "meaner" than the poster boy for environmental indifference, the Hummer H2, which still made the list of least green vehicles.

Meanest 2008 Vehicles

• VOLKSWAGEN TOUAREG 
• BUGATTI VEYRON
• MERCEDES-BENZ GL320 CDI
• JEEP GRAND CHEROKEE
• MERCEDES-BENZ R320 CDI

Fuel economy for all 2008 model year vehicles remained the same as the prior year, but shamefully is still below what it was in 1986.