5 Things You Need to Know About Ethanol

Ethanol, E85, Gasoline, and RFG

In the U.S., ethanol - ethyl alcohol - is currently produced from corn. It is essentially the same as grain alcohol used in whiskey and moonshine. Pure ethanol is blended with small amounts of gasoline to improve engine starting and, since pure ethyl alcohol burns with a colorless flame, it could be a safety hazard. E85, a blend of 85 percent ethanol and 15 percent gasoline, is sold as a fuel. E85 should not be confused with gasohol, which is only 10 percent ethanol and 90 percent gasoline, Gasohol, or E10, is not considered an alternative fuel. A smaller amount of ethanol, typically about 2 percent, is used as an oxygenate in cleaner burning reformulated gasoline, or RFG.

Fuel from Domestic Sources

Unlike gasoline, ethanol can be produced from domestic feedstocks, not imported petroleum. While the benefits of using E85 might be small on a per-vehicle basis, if used in millions of vehicles the results could be a rather dramatic and help reduce the nation's dependence on imported oil. Besides being a renewable biofuel, burning ethanol results in modest reductions of harmful hydrocarbon and benzene emissions as well as reduced carbon dioxide.

What is an FFV?

Because of the limited availability of E85, automakers offer flexible fuel vehicles, or FFVs, that can operate on E85, gasoline, or any combination of the two. Since the late 1990s, Ford, GM, Chrysler, and other automakers have sold millions of FFVs. Unfortunately, most of these FFVs have never seen E85 in their tanks. That's because there are only about 1500 E85 stations in the U.S., most located in or near corn growing states. The 1988 Alternative Motor Fuels Act provided incentives to automakers to produce alternative fuel vehicles, but no companion incentive for developing of the required refueling infrastructure.

E85 and FFVs Go Together

Modifying an engine to operate on E85 is pretty simple: add a fuel sensor to detect the ratio of ethanol to gasoline, replace fuel system components that are not compatible with the more corrosive ethanol, and reprogram the engine management computer. While these modifications are simple, they are required to burn E85. That said, E85 should not be used in vehicles other than FFVs. Should you accidentally fill a non-FFV with E85, it probably won't not do any harm. However, the CHECK ENGINE warning light might start glowing because the oxygen sensor in the engine management system measures a higher oxygen level. Using E10 and lower ethanol blends should cause no problems.

Performance Differences

Drivers will probably not notice any difference between operating on E85 versus
gasoline. While ethanol produces less energy than gasoline, it has a higher octane rating. Typically, there is a 5- to 15-percent decrease in fuel economy depending on operating conditions. Currently, E85 is more expensive because of the added cost to blend ethanol with gasoline as well as the added cost to ship E85 into areas where corn is not grown. Adding to cost is that currently ethanol production must compete with other uses of corn, namely food.

Bill Siuru is a retired USAF colonel who has been writing about automotive technology for nearly 40 years. He has a bachelor's degree in automotive engineering, a PhD in mechanical engineering and has taught engineering at West Point and the U.S. Air Force Academy.