Catalyst Fall 2012


Electric Vehicles Spark Readers’ Curiosity

In the spring Catalyst article on electric and hybrid cars [“How Clean Are Electric Vehicles?”], you fail to mention Tesla. The Model S is expensive, true, but its top-of-the-line model goes 300 miles (at 55 mph) on a single charge. If I want to go to San Francisco (120 miles round-trip), I cannot get there and back [on one charge] in a Nissan Leaf. The Chevrolet Volt doesn’t work, either. Once the battery is exhausted, the Volt gets about 30 mpg [miles per gallon], so the round trip in my Prius (close to 50 mpg) uses less gas.

E. Blake Peterson
Santa Rosa, CA

I enjoyed reading your analysis of the relative carbon emissions of EVs [electric vehicles] due to upstream power plant emissions based on geography [“How Clean Are Electric Vehicles?”]. Your article states it used a “well-to-wheels” approach; was this true for gasoline as well?

Greg Hanssen
Irvine, CA


The author responds:

Though we focused on GM and Nissan, they are not the only automakers offering EVs. Tesla has long been a leader in the market; though it is known for its $100,000 sports car, it recently introduced the Model S sedan, which comes with multiple driving range options and starts at “only” $57,400. Tesla’s EVs don’t yet accommodate the average driver’s budget, but its engineering and technology development have helped advance the market as a whole. For example, the only all-electric SUV currently on the market, Toyota’s RAV4 EV, is propelled by a Tesla powertrain. Consumers can expect longer driving ranges and even more EV options to choose from in the years ahead, as other automakers (including BMW, Ford, Honda, and Toyota) introduce their plug-in hybrid and all-electric models.

With regard to the “well-to-wheels” approach we used in our analysis, we did indeed measure “upstream” emissions (i.e., those associated with fuel production) for both EVs and gasoline vehicles. For EVs, these include the global warming emissions from mining or extracting the fuel used to generate electricity (e.g., coal, natural gas), transporting that fuel to the power plant, and burning it in the plant. All of an EV’s emissions are considered upstream since the vehicle produces no tailpipe emissions. Gasoline’s upstream emissions come from the extraction, transportation, and refining of oil, and account for about 20 percent of a vehicle’s overall emissions; the remaining 80 percent is generated by the burning of the gasoline in the vehicle.

Don Anair, senior engineer, UCS Clean Vehicles Program