The American Council for an Energy-Efficient Economy (ACEEE) considers the 2014 Smart ForTwo Electric the ‘greenest’ car in the U.S. market. The car topped the organization’s Greenercars.org 2014 Environmental Scores list with a 59 out of 100 score, the highest ever for the program. Also on the ‘greenest’ list, in descending order: the Toyota Prius C; Nissan LEAF; Toyota Prius; Honda Civic Hybrid; Lexus CT200h; Toyota Prius Plug-In Hybrid; Mitsubishi Mirage; Honda Civic Natural Ga;, Honda Insight; Smart ForTwo Convertible/Coupe; and the  VW Jetta Hybrid.

How does this work? Greenercars.org assigns each vehicle a ‘Green Score’ that incorporates lifecycle greenhouse gas and criteria pollutant emissions. Changes were made to the methodology this year to more accurately quantify environmental impacts, including updates to evaporative emissions estimates; in-use emissions of methane and nitrous oxides; and gasoline, diesel, and natural gas ‘upstream’ emissions. Vehicles not intended to achieve significant sales volumes are not eligible for spots on the “Greenest” list.

 

Recent media coverage of electric vehicles has featured claims of high environmental impact due to the production and disposal phases of the vehicle life cycle. ACEEE’s Green Book, which evaluates such impacts for real vehicle models, helps put this issue into perspective.

Among model year 2012 vehicles, production and disposal emissions were about 30 percent higher for EVs than for comparably-sized conventional vehicles, due to relatively high per-pound battery production emissions. And while these ‘embodied’ emissions accounted for 22 percent of total vehicle impacts on average, they were just above half for EVs.

Nonetheless, EVs received very high Green Scores, reflecting low environmental impact, not a surprise given their zero in-use emissions. And of course, their scores will climb further if and when the ‘upstream’ emissions associated with electricity generation decline.

More broadly, as vehicles’ in-use emissions and energy consumption fall, production and disposal will indeed be increasingly important determinants of environmental impact. Material substitution to reduce vehicle weight, which in turn allows downsizing of vehicle systems and further weight reduction, is already a key strategy to boost fuel economy. Production of advanced, lightweight materials can be energy-intensive, and net impacts will reflect this, together with material recyclability and the fuel savings these materials enable. But careful analyses of these considerations to date have shown a clear net reduction in energy use and GHG emissions from the use of high-strength steel and aluminum, for example.

The recent light-duty vehicle fuel economy and GHG emissions rule provoked a lively discussion of the possibility of standards based on full life cycle emissions. At present, this would be quite a challenge, given the paucity of data on the content and production of individual models and differing views on life cycle analysis.

And for now, fuel economy remains the undisputed heavyweight in vehicle environmental impacts. But we should prepare for a time when, thankfully, that will no longer be the case.

 

Therese Langer is Transportation Program Director of the American Council for an Energy-Efficient Economy, www.ACEEE.org

 

After spending four months in São Paulo, I’m taking a more expansive view of feasible policy options. Car ownership is still low in Brazil, but in wealthy São Paulo it’s far higher and growing at breakneck speed. Daily paralysis of major thoroughfares has led to implementation of a ‘rodízio’ prohibiting certain license plates from circulating each day during peak periods.

In terms of energy impacts, however, Brazil’s new automobiles have an edge over those in the U.S. More than 80 percent of light-duty vehicles sold last year were flex-fuel vehicles. Ethanol consumption varies greatly with price, but it accounted for close to 40 percent of car and light truck fuel consumed in 2010. And Brazil’s sugar-cane-based ethanol is said to be substantially less carbon-intensive than the corn ethanol used here.

In addition, the average fuel economy of Brazil’s vehicle stock is about 26 miles per gallon, in energy-equivalent terms, while the U.S. value stands at 23 miles per gallon. That’s largely a reflection of engine size, not technology – over 90 percent of the vehicles sold in Brazil in 2011 have engines of 2.0 liters or less. A tax differential of 18 percentage points between a 1.0-liter and a 2.5-liter engine helps to explain this. Plus, gasoline in Brazil costs about 40 percent more than in the U.S.

Now there’s a major new vehicle tax policy in the works, and it’s tied to fuel efficiency. With substantial and rapidly growing oil production, Brazil is a net petroleum exporter.

And climate change concerns are not driving policy at this time. So who’s worried about fuel economy? The President herself, along with the Ministry of Development and Commerce: the new tax regime would replace the 30 percent tax that Brazil slapped on imported vehicles last fall. That policy has come under fire at the World Trade Organization, and there’s a sense that that approach to keeping imports at bay won’t fly in the long run. So fuel efficiency is the new competitiveness policy for the Brazilian auto industry. Sound familiar?

 

Therese Langer is Transportation Program Director of the American Council for an Energy-Efficient Economy, www.ACEEE.org