Debunking Ethanol Myths
A lot of misinformation about ethanol circulates on the airwaves and the Internet, leaving consumers and opinion-makers confused about ethanol’s economic and environmental costs.
Let’s tackle three of the most common ethanol objections:
-
Producing ethanol isn’t energy efficient.
Numerous studies have shown that ethanol has a positive energy balance, particularly when compared with gasoline. According to the U.S. Department of Energy, it takes 1.23 units of fossil energy to make one unit of gasoline31 – an energy cost of 23 percent. In contrast, corn ethanol delivers 20 to 50 percent more energy than it takes to produce, and cellulosic up to 600 percent more32. The U.S. Department of Agriculture says this: “For every BTU dedicated to producing [corn] ethanol, there is a 34 percent energy gain.”33
-
Ethanol is expensive to produce.
Producing corn ethanol in the U.S. currently costs about $1.50 to $1.60 per gallon, but it is produced for significantly less elsewhere. In an article from fall 2005, the Rocky Mountain Institute pointed out that Brazilian ethanol was selling in New York for $1.10 a gallon, despite an import tariff of 54 cents a gallon.34 Producing cellulosic ethanol – a new technology just beginning to develop its potential – costs more than producing ethanol from corn. However, the cost to produce cellulosic ethanol will go down as the industry implements new technologies and efficiencies.
-
Ethanol lowers your gas mileage.
It’s true that ethanol contains less energy than gasoline, but for vehicles using E10, the lower energy content of ethanol does not adversely affect fuel efficiency. E85-fueled cars experience about a 17 to 25 percent decrease in mileage, depending on speed and terrain.
Concerns about the fuel efficiency of higher-blend ethanol can be overcome. Although ethanol has less energy per gallon than gasoline, its octane rating is higher than gasoline’s, which can counterbalance its lower energy content when blended in higher concentrations. Octane measures a fuel’s ability to resist premature ignition of the compressed fuel and air mixture. Using a higher octane fuel allows engines to have higher compression ratios, which increase the engine’s thermal efficiency. As a result, an engine designed with a higher compression ratio can be far more efficient than a gasoline engine. Improvements in flex-fuel vehicle engine design, such as direct fuel injection, and engines with variable compression capability, which takes advantage of ethanol’s specific characteristics, can also improve flex-fuel vehicle mileage. A prototype car engine recently developed at the Massachusetts Institute of Technology uses injections of ethanol into a car’s cylinders to increase the combustion efficiency. The result is a 30 percent increase in miles per gallon.35