At the moment, regular automotive fuel can contain no more than 10 percent ethanol, according to federal law. But with tight energy supplies promising to be a long-term issue, ethanol producers are making a strong push to consider letting Americans fill their cars with fuel that contains up to 20 percent ethanol.
Many lawmakers and government officials are interested, in part because they believe that boosting ethanol levels could help lower American dependence on foreign oil.
But the idea has many critics, including automakers and government regulators who are concerned about potential structural damage to car parts and emissions control systems. Ethanol blends already have been accused of damaging boat motors and lawn equipment, which are more vulnerable to such problems because of their designs. And corn-based ethanol continues to be attacked as being energy inefficient and a factor in rising food prices.
Earlier this month, government researchers released preliminary results from a multiyear study of the impact of various blends, including 15 percent and 20 percent ethanol, on vehicles and other types of engines. (The findings will be critical to receiving the Environmental Protection Agency's approval for any future changes). According to Brian West, the study's lead author and a researcher at the Department of Energy's Oak Ridge National Laboratory in Tennessee, the findings "were not discouraging, but we need to stress there is more testing to be done."
On the positive side, overall emission levels didn't change dramatically with ethanol content, nor did researchers detect any serious operability problems, such as fuel leaks or the appearance of malfunction indicator lights.
But, as the researchers noted, it's future tests that pose a greater likelihood of revealing problems. The first tests were carried out in a relatively short time frame. Most test vehicles logged only a few hundred miles. Serious problems, most experts say, won't arise until cars accumulate significant mileage over a longer period of time. Over the next year, West and his colleagues will be running 80 test vehicles for at least 50,000 miles each, long enough to begin to detect problems with structural components or emissions-system deterioration.
Automakers will be watching the results closely. High-mileage tests done in Australia within the past few years on 20 percent ethanol blends revealed significant performance issues, including rusting of some components and catalyst damage. One of the main problems, the tests found, is that ethanol raises the temperature at which reactions take place inside the car and can therefore accelerate damage and decay.
The preliminary DOE results released this month also showed an increase in catalyst temperatures under certain conditions, raising concerns among automakers. "The way this process works is that a small change in temperature produces a very large change in behavior," says Coleman Jones, General Motors' manager for biofuels implementation. "The bottom line is that we need to test it. We need to test it thoroughly, because these guys are proposing to change gasoline for all of us, forever."
GM and other automakers say they aren't opposed to putting ethanol in their cars but would prefer to see it used in flex-fuel vehicles, which usually run on E-85, a blend of 85 percent ethanol and 15 percent gasoline or other hydrocarbons. Flex-fuel vehicles are a growing market in the United States, but relatively few gas stations carry E-85. "We've said we're not a 'no' to E-20," Jones said, but he added that ethanol blending mandates adopted by Congress last year—36 billion gallons of ethanol by 2022—are not going to be met without the use of flex-fuel vehicles.
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