A new study suggests that ethanol-blended fuel could take a toll on vehicles when used in higher concentrations.
Renewable-fuels trade groups blasted the results, but auto industry groups warned of the dangers of rushing new fuel blends into the marketplace.
The study found that vehicles running on E15 and E20, or fuel blends of 15 percent and 20 percent ethanol, were more susceptible than vehicles running on regular gasoline to damaged valves and valve seats, which can result in decreased compression and power, misfires, engine damage, poorer fuel economy and increased emissions.
Engineering company FEV Inc. conducted the study for the Coordinating Research Council, whose members are engineers from the auto and oil industries. FEV tested 28 engines from eight vehicle types for 500 test cycles, or 500 hours.
Questions arise
Kristy Moore, vice president of technical services for the Renewable Fuels Association in Washington, said "no amount of testing" could calm the fears of those opposed to use of fuel with higher ethanol concentrations.
Moore said a similar Department of Energy study of E10, E15, E20 and regular gasoline found that engine failures weren't attributable to ethanol, but rather normal wear-and-tear. During the Department of Energy project, 86 vehicles were tested while running on the fuels for 120,000 miles.
"All of our studies show, between E10 and E15, there is very little chemical difference and very little difference in vapor pressure. In most cases, the fuels are indistinguishable," Moore said. "With the minimal differences, there will be no engine performance problems. As far as the fuel operating in today's engines, there will be no issues."
Patrick Davis, the Department of Energy's vehicle technologies program manager, said in a statement that the new study's "choice of test engines, test cycle, limited fuel selection and failure criteria resulted in unreliable data, which severely limits the utility of the study."
The department was critical of the decision to disregard E10.
Most gasoline is E10
But automakers didn't build vehicles "to handle the more corrosive E15 fuel," Alliance of Automobile Manufacturers President Mitch Bainwol said in a statement.
The alliance represents 12 automakers, including the Detroit 3 and Toyota Motor Corp.
E10 accounts for 90 percent of gasoline available in the United States, according to the EPA. The agency has allowed use of E15 in flexible-fuel vehicles and 2001 model and newer light vehicles.
"Automakers believe that renewable fuels are an important component of our national energy security, but it is not in the longer term interest of the government, vehicle manufacturers, fuel distributors or the ethanol industry itself, to find out after the fact that equipment or performance problems are occurring from rushing a new fuel into the national marketplace," Bainwol said.
In March 2009, Growth Energy, an ethanol industry trade group, petitioned the EPA to raise the ethanol limit from 10 percent to 15 percent.
The EPA granted partial waivers of Clean Air Act standards starting late the following year allowing the sale of E15, first in October 2010 for 2007 and newer models, then in January 2011 for 2001-06 models.
Growth Energy CEO Tom Buis and Moore said the waiver approval process for E15 was the EPA's most detailed yet for a fuel standards change.
Buis said that waiver decisions are normally made within 270 days, but EPA extended the process by contracting with the Department of Energy to run tests on E15 before giving the green light.
Using more ethanol is vital because the nation can't continue to "kick the can down the road" and continue its dependence on foreign oil, he said.
But the Association of Global Automakers, which represents import vehicle manufacturers, says careful testing is needed.
Said CEO Mike Stanton in a statement: "Our goal is to ensure that new alternative fuels are not placed into retail until it has been proven they are safe and do not cause harm to vehicles, consumers, or the environment."