| September 1, 2006 |  |
Vehicle Updates from the Union of Concerned Scientists
Consumer Reports Finds Ethanol Worsens Vehicle Fuel Economy
A new study by Consumer Reports shows that when flexible-fuel vehicles (FFVs) run mostly on ethanol instead of gasoline, the vehicle's fuel economy drops and fueling costs rise. This is not surprising, according to calculations by the Union of Concerned Scientists (UCS).
Consumer Reports test drove a 2007 Chevy Tahoe flex-fuel vehicle and found that the vehicle's fuel economy dropped by 27 percent when fueled by E85 (a fuel that is 85 percent ethanol, 15 percent gasoline) rather than conventional gasoline. "Ethanol has a lower energy content than gasoline, so consumers need to be prepared for a dip in gas mileage," says Don MacKenzie, a UCS vehicles engineer who served as a technical reviewer to Consumer Reports. "That said, E85 does reduce global warming emissions by 8-16 percent on a per-mile basis."
The reduction in global warming pollution is achieved because ethanol is made in large part from corn, which reduces the amount of fossil energy used to produce the fuel. Even larger reductions in petroleum use are achieved, since natural gas, rather than oil, is the main fossil fuel used to make ethanol. Emerging technology may reduce global warming emissions from ethanol much further, by making it possible to use a greater variety of feed materials and utilize a larger portion of the plant.
Although E85 usually costs less per gallon than gasoline, the cost is not low enough to make up for the lower energy content of the fuel. Over the past year, E85 has cost about 20 percent more than gasoline, after adjusting for the energy content.
No matter what fuel is used, FFVs aren't as efficient as the average new vehicle. Every year since 1998, FFVs have offered lower fuel economy than the average gasoline vehicle, a gap that has grown in recent years. "The average FFV sold in 2005 gets almost 5 miles per gallon less than the average vehicle, even before it takes the additional hit from using E85," said MacKenzie. "A Chevy Tahoe burning E85 still produces 12-25 percent more global warming pollution than the average car because of all the extra fuel it uses. If the automakers are serious about making flex-fuel vehicles a responsible environmental choice, they need to improve the fuel economy of all their vehicles and offer flex-fuel capability on all models rather than focusing on gas guzzlers."
The Union of Concerned Scientists is urging the Environmental Protection Agency to educate car shoppers by including accurate mpg, cost, and environmental performance information on the fuel economy window stickers of new FFVs. EPA announced earlier this year that it would revise its standard window stickers after consumers complained that EPA's fuel economy numbers did not reflect real-world performance.
Test Drive of Saturn "Hybrid" Vue
Our Vehicles Director, Jason Mark, recently had a sneak peak of the Saturn Vue Greenline, a car that General Motors is calling a hybrid. The review? Nice use of conventional efficiency technology, but it's not a hybrid. The new Vue uses a small battery pack that allows the car's engine to turn off at a stoplight and instantly start up again upon pressing the accelerator, saving fuel otherwise wasted during idling. EPA says the Greenline Vue boosts fuel economy by 20 percent compared to conventional models. That's half the fuel economy gain of real hybrid SUVs on the market today, which also use their electric systems to reduce fuel use during normal driving and capture more wasted energy from vehicle braking. Still, the Greenline Vue is nothing to sneeze at. The engineers did an excellent job making the engine start and stop relatively seamlessly (in fact, better than some hybrids on the road).
The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with citizens across the country, we combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future.
