Honda's natural gas-powered Civic GX won greenest honors in the 14th annual environmental ratings released on February 16 by the American Council for an Energy-Efficient Economy (ACEEE). This is the eighth year in a row the Civic GX has received the highest ranking in the nonprofit organization's "Green Book Online." The all-electric Nissan Leaf placed second in the 2011 model year evaluation, followed by the gasoline-powered Smart Fortwo. Hybrids took the next three spots in this year's competition. Because of their refinements in transmissions, weight savings, and sophisticated internal combustion engines, fuel-sipping gasoline vehicles were also among the top cars. Ford Motor Company's new Fiesta SFE (super fuel economy) and General Motors Co.'s Chevrolet Cruze Eco finished in the top 10. Because of a statistical tie between the Mazda 2 (manual transmission) and the Chevrolet Volt, the list was expanded to 13 vehicles from the traditional dozen.
This year's Green Book methodology was updated to incorporate emissions associated with battery manufacture and disposal. This revision was based on a model created by DOE's Argonne National Laboratory. By way of explaining the scores for plug-in vehicles, ACEEE officials said that even though a vehicle might emit nothing from the tailpipe, its "upstream" emissions from power generation could be substantial. As U.S. power generation becomes cleaner, these vehicles' scores will rise.
Reprinted from EERE Network News, a free newsletter from the U.S. Department of Energy.