CNG Honda Civic Tops Nissan Leaf in Annual Green Car Rating BookBy John O'Dell February 15, 2011
More than Half the Top 13 for Environmental Friendliness are Gasoline Burners
(Note: Because of an error in ACEEE's original calculations, the Chevrolet Volt's ranking in 12th place on the greenest cars list has vbeen revised. the range-extended plug-in hybrid actually finished 13th per the ACEEE rating methodology, with the 1.5-liter, manual transmission Mazda Mazda2 subcompact replacing it in the12th position. You can read about the change here, and we've modified the chart, above, to reflect the new order.)
If you think your Leaf is the greenest thing on the highway except for the fresh clippings the lawn guy's pickup is dribbling onto the road up in front of you, think again!
The 2011 Honda Civic GX, a car with a natural-gas burning internal combustion engine, topped the battery-electric Nissan Leaf, Chevrolet's plug-in hybrid Volt and hundreds of other models to take top spot for the eighth consecutive year in the respected ACEEE Green Book environmental ratings for passenger cars and light trucks sold in the U.S.
Of more significance than the topmost ratings, which went to cars with limited market penetration, is that half the cars on the list are conventional gasoline-burners. It stands as proof that automakers here and abroad can build highly efficient and environmentally clean cars (albeit all are compacts or subcompacts) without expensive technology upgrades.
The trick is that most make use not only of sophisticated engine tuning and multiple-speed manual transmissions but of new lightweight materials. There are no Lincolns or Mercedes-Benzs on the list because "lightweighting" has greater impact on a small car's fuel economy than on that of a larger vehicle.
The Chevy Volt, which uses both an electric motor and a gasoline generator, finished
12th 13th on the list of the cleanest production vehicles, in large part because its fuel economy when using its gasoline generator isn't all that great, leading to a relatively hefty emissions output compared to others on the list.
The Volt, for example, is rated at 35 mpg in the city and 40 mpg on the highway using its generator, versus the gas-electric Toyota Prius' rating of 51 mpg city and 48 mpg highway.
The Volt also suffers in comparison to the Leaf when using its all-electric mode because it is the heavier of the two, meaning its gets fewer miles of range per kilowatt-hour of electrical power than the Nissan, said Shruti Vaidyanathan, lead analyst for the ACEEE's Green Book project. The group - American Council for an Energy-Efficiennt Economy, is a respected Washington-based environmental lobby.
Chevy's Volt got an ACEEE green score of 48, versus 54 for both the Civic GX and the Nissan Leaf (the Leaf landed in second place despite having the same overall rating as the Honda because the GX (right) has a lower overall pollution rating, which counts more than fuel economy.)
In third place at 53 points was the Smart Fortwo with a 1-liter gas engine.
The Smart's battery-electric stablemate, the new Smart Fortwo ED (electric drive) actually outdid both the Leaf and the Civic GX, scoring 60 points, but it is not considered a production car because only a limited number are available this year for testing under a small lease program.
When the Smart ED and several other mass-market electric city cars such as the Mitsubishi i-MiEV and the Think City come into the market next year, the Civic GX may finally be dethroned, said ACEEE analyst Vaidyanathan.
That would be ironic because until now, the natural gas Civic, despite its green credentials, has been sold in only a few states, but Honda announced last month that with the redesign of the Civic lineup for the 2012 model year, the Civic GX finally would become a 50-state car.
The Green Book, now in its 14th year, bases its ratings on a weighted score derived from federal and state emissions and federal fuel efficiency ratings as well as formulas widely used by government and industry to calculate emissions at the factory, the environmental impact of disposing of and recycling vehicle components at the end of their useful lives, the impact of producing the fuels they use - and in the case of battery-electrics and plug-ins, the production of battery materials - and the public health impacts and costs of vehicles' emissions.
Thus Honda, which hasn't had a lot to crow about lately, scored well with the Civic GX despite its tailpipe emissions. That's because the Green Book team looks at upstream impacts as well as on-road impacts in evaluating vehicles and electrical power production can be pretty dirty compared to natural gas.
Conventional hybrids did well also, with the Toyota Prius finishing forth overall with 52 points and two Hondas - the Civic and Insight hybrids - in fifth and sixth place with 51 and 50 points, respectively.
The ACEEE's use for the first time this year of vehicle disposal and recycling data developed by Argonne National Laboratory shook up the listing a bit because the mining of nickel for conventional hybrids' nickel-metal hydride batteries is pretty dirty, environmentally speaking.
Thus the Prius dropped from second to fourth place and both the Ford Fusion and Nissan Altima hybrids, the largest cars on the "greenest" list last year, dropped off to top dozen for 2011.
Diesels continued to fall just short of the top dozen list; their exceptional fuel economy has been unable to overcome the impact of emissions which, while cleaner than ever, still contain more harmful pollutants than gasoline emissions.
You can see the Green Book's Greenest and Meanest list, replete with emissions standards and fuel economy ratings, as well as lists of the greenest choices in several size segments - the Ford F150 flex-fuel pickup in the full-size pickup segment and the Hyundai Tucson and Chevrolet Equinox crossovers lead their categories, for instance - on ACEEE's Green Book website.
In all, the book lists more than 1,000 vehicles, with individual models broken down by available engine and transmission combinations.