Is Ethanol Fuel The Answer?
With the number of flex-fuel–capable vehicles increasing with each passing year and the number of fueling stations growing as well, it’s time we take a look at the most common alternative fuel. Ethanol is one of the fastest growing gasoline alternatives and is the same type of alcohol that is commonly found in distilled spirits. That’s right, the same ingredient that makes whiskey so good can also be used to fuel your truck. Using the same basic method as the legendary moonshiners of Appalachia, ethanol is produced by the distillation of fermented corn or sugarcane. After distillation, the ethanol goes through a process of dehydration, which removes any remaining water, thereby allowing it to be burned in an internal combustion engine.
The fuel most commonly found at the pump is referred to as E85: a blend of 85 percent ethanol and 15 percent gasoline (though blends containing anywhere from 51 to 83 percent ethanol can be described as E85). An old wives’ tale that we have always loved is that ethanol needs to be blended into E85 as a way of preventing people from drinking it. The reality is that to fully take advantage of pure ethanol, an engine would need a much higher compression ratio than is common, so by mixing it with gasoline, normal engines can better utilize the fuel. A blend is also utilize to help mitigate the negative effects that straight ethanol can have on a standard vehicle fuel system and slow the process of water absorption.
Flex-fuel vehicles (FFV) are ones that are designed to run on any mixture of gasoline and ethanol, up to an 85 percent blend. There are a few major differences found between FFVs and non-FFVs. First is that FFVs lack any bare magnesium, aluminum, or rubber in the fuel system. Another difference is that FFVs have fuel pumps capable of safely operating with the electrically conductive ethanol (gasoline does not conduct electricity). Stainless steel fuel lines and plastic tanks are used instead of steel (though most of the auto industry has gone this way already). And fuel injection control systems must be able to inject approximately 34 percent more fuel to compensate for the difference in energy density. Some (particularly older) fuel systems contain rubber gaskets, seals, and hoses, which have poor ethanol resistance and tend to break down when exposed to the fuel. These vehicles can generally accept up to a 10-percent ethanol blend (E10), which has become an increasingly common blend of standard gasoline, without major issues.
One of the biggest complaints often heard about the use of E85 is its poor fuel economy. While E85 does carry a higher octane rating than gasoline, typically 100-105 depending on blend, it contains about 30 percent less energy per unit as compared to gasoline. Simply, this means that people often cite a large drop in fuel economy when running on E85. To test this for ourselves, we lined up two FFVs: a ’15 Ford F-250 Super Duty powered by a 6.2L V-8 engine and a ’14 Range Rover Sport with the company’s supercharged 5.0L V-8 engine stuffed under the hood.
Our very unscientific test involved driving both vehicles on similar routes, first on gasoline and then on E85. With the F-250 running on gasoline we averaged 12.5 mpg. After making the switch to E85, it knocked down 11.7 mpg. This accounted for a seven percent drop in economy. In the Rover we netted a 14.1 mpg average on gasoline and 10.1 mpg on E85, a far more drastic 28 percent drop in fuel economy.
So what did we learn from this test? Yes, there is a drop in fuel economy anywhere from negligible to nearly 30 percent, and it all depends on the vehicle and your driving style. Could we have gotten better economy? Sure. Could we have done worse? You bet! The bottom line is, is ethanol worth it? The answer is no. From a straight cost perspective, driving the F-250 Super Duty on E85 provided no savings over regular unleaded gasoline. The Range Rover required more expensive premium fuel from the start, but with a much larger discrepancy in economy, it ended up costing six cents more per mile to drive on E85, which, over time, adds up to quite a bit of dough.
Right now in California we’re seeing about a 15 percent difference in price between E85 and regular unleaded (with E85 typically being less expensive), meaning for us to want to use it, we’d need a FFV with a fuel economy discrepancy closer to that of the Super Duty than the Range Rover. For our money, it’s still a better bet to drink the distilled corn than to burn it.