The new all- electric vehicles from Chevrolet and Nissan are attracting a lot of attention, as is appropriate for such a new entry into the automobile market. There’s no question that they are better for the environment than a Hummer, but not as much as most of the articles I have read claim. Slate reports:
According to the EPA, the Leaf gets the equivalent of 99 miles per gallon—106 MPG in the city and 92 MPG on the highway, with an estimated annual electricity cost of $561. That would make the Nissan Leaf (shown in the photo) about twice as efficient as the Prius. More important for its long-term viability, though, is that it’s twice as fun.
I don’t know how EPA makes the calculation, but it seemed to confuse the author of the piece when later in the story he wrote:
Electric motors are simply far more efficient than gasoline engines; the internal-combustion engine uses only a fraction of its fuel for forward motion (most of it is wasted on heat), while electric motors are 90 percent efficient. Today, that kind of efficiency sounds out of this world, and as you drive around in the Leaf—mine included an ostentatious “zero emission” sign plastered on one side—people will certainly notice you. I
“[T]hat kind of efficiency” is indeed out of the world. The author, Farhad Manjoo, failed to account for the energy lost in the production and delivery of the electricity to the car. I don’t have these numbers at hand, but when the whole life cycle is considered, the apparent efficiency gains shrink. And as for the advertising of zero-emissions, Nissan should be hailed into liar’s court. The PR people at Nissan conveniently overlooked emissions at the coal- or other fossil fuel-fired power plant. Great for the neighbors of the car owner, but not good for the neighbors of the generating plant. It’s possible that they assumed the electricity would be coming from a hydroelectric or solar-powered plant, but there’s not enough to matter.
This example of the mechanics of the car itself and the kind of faulty reporting about it that so often goes along with stories about some form of clean or green technology is a form of greenwashing that will do little or nothing to the creation of sustainability. In the long run, the those who are lulled by the 100-mpg EPA rating and by the promise of zero emissions may sit back and relax, assuming they have done their part for sustainability. No way. The connection of electric vehicles to sustainability is very complicated. The relative performance of different powertrains–internal combustion, all-electric, or hybrid–depends on what measure is being used. If you are concerned about global warming and greenhouse gases, the hybrid is the best because it generates some of the energy from its inertia and uses less CO2 producing fossil fuel. If you are concerned urban smog, the all-electric is the best.
If you really want to contribute to sustainability: walk, ride a bike, or use public transportation.