September 6, 2006
Ethanol offers cleaner emissions but poorer fuel economy, says Consumer Reports
Yonkers, New York – Tests and an investigation conducted by Consumer Reports conclude that E85 ethanol will cost consumers more money than gasoline, and that there are concerns about whether the government’s support of flexible fuel vehicles is really helping the U.S. achieve energy independence.
The report found that E85 (85 per cent ethanol, 15 per cent gasoline) emits fewer smog-producing pollutants than gasoline, but provides fewer miles per gallon, costs more, and is hard to find outside the Midwest. The report also says that government support for flexible-fuel vehicles (FFVs), which can run on either E85 or gasoline, is indirectly causing more gasoline consumption, rather than less, and that ethanol, blended with gasoline, has the potential to fill a significant minority of future U.S. transportation fuel needs.
The magazine’s researchers tested a 2007 Chevrolet Tahoe FFV in a variety of fuel economy, acceleration and emissions tests. Overall economy on the Tahoe dropped from an already-low 14 mpg US (16.8 L/100 km, or 17 mpg Imp) to 10 mpg US (23.5 L/100 km, or 12 mpg Imp). The researchers say that any current FFV would experience a similar decrease, as ethanol has a lower energy content than gasoline (75,670 BTUs per gallon instead of 115,400 for gasoline) and more fuel must be burned to generate the same amount of energy.
The magazine says that with the retail pump price of E85 averaging US$2.91 per gallon in August, a 27 per cent fuel economy penalty means drivers paid an average of US$3.99 for the energy equivalent of a gallon of gasoline.
Tests also showed that the Tahoe’s driving range, on a full tank of E85, decreased to about 300 miles (483 km), compared with about 440 miles (708 km) on gasoline, meaning that motorists using E85 would have to fill up more often. Out of 176,000 gas stations nationwide in the U.S., only about 800 sell E85 to the public, and are mostly in the Midwest where corn to make ethanol is grown. However, the Tahoe did have a significant decrease in smog-forming oxides of nitrogen when using E85.
The Big Three domestic auto manufacturers have built more than five million FFVs since the late 1990s, and will build about one million this year.
“A strong motivation for that is that the government credits FFVs that burn E85 with about two-thirds more fuel economy than they actually get using gasoline, even though the vast majority may never run on E85,” the magazine states. “This allows automakers to build more large, gas-guzzling vehicles that they otherwise could under Corporate Average Fuel Economy rules. As a result, these credits have increased annual U.S. gasoline consumption by about one per cent, or 1.2 billion gallons, according to a 2005 study by the Union for Concerned Scientists.”
However, the magazine reports that ethanol reduces demand for gasoline. “Experts agree that the maximum amount of ethanol you can get from corn in the U.S. is about 15 billion gallons,” the magazine states. “But scientists are working on producing ethanol from other plant material, called cellulose, which could increase this capacity by as much as 45 billion gallons. For comparison’s sake, the U.S. burned 140 billion gallons of gasoline in 2005.”