Ethanol is an alcohol derived from agricultural products, such as corn. It can also be produced from cellulose products, such as paper and wood waste products. Very few vehicles on the road today run on pure ethanol. However, ethanol is often mixed with gasoline to create various blends. The most common of these blends are E10 (10% Ethanol, 90% gasoline), E15 (15% ethanol, 85% gasoline), and E85 (85% ethanol, 15% gasoline).
The rising demand for alternative fuels combined with the increasing demand for ethanol blended gasoline has led to a rapid increase in ethanol consumption. The U.S. produced a record 13.3 billion gallons of ethanol in 2012. The bulk of this production came from the increasingly ubiquitous nature of E10 and other low-level ethanol blends (E12, E15, etc…), as nearly all gasoline sold in the U.S. contains at least a 10% ethanol blend. Conversely, E85 represents a very small percentage of the total ethanol consumed and is still considered a specialty fuel.
E85 consumption increased drastically between 2010 and 2011. Recording an 52% increase during that time period.
There are many advantages to using ethanol. A major reason the U.S. government is encouraging the consumption of ethanol is due to the fact that ethanol is produced domestically, thus decreasing dependence on petroleum from oversees. In 2009, ethanol consumption reduced demand for imported oil by an estimated 364 million barrels, at a savings of $21.3 billion. There is less wear and tear on the engine when using ethanol because the fuel burns better, thus leaving less carbon deposits. In addition, the 102 octane rating helps prevent engine knock damage. Pure ethanol offers low emissions of hydrocarbons and other toxins.
However, there are disadvantages to ethanol. To begin with, higher-level blends like E85 can only be used in flex-fuel vehicles. Also, the vehicle range is limited compared to gasoline or diesel-powered vehicles. A flex-fuel vehicle operating on E85 usually experiences a 20%-30% drop in miles per gallon due to ethanol’s lower energy content. The final disadvantage is limited availability. While the low-level blends like E10 are widely available, the high-level blends are a bit harder to find. In fact, low-level ethanol blends like E10 already constitute much of the gasoline sold in the United States, yet the number of public fueling stations that supply E85 is only 2,354. This is not a large amount considering there is an estimated 160,000 gasoline serving stations in the United States.
Additionally, the distribution of fueling stations that supply E85 is far from uniform throughout the United States. In fact, over 75% of fueling stations that supply E85 are located in the Midwest.
Another disadvantage of ethanol is the price. In April 2013, E85 had a national average price per gallon that was $0.29 cheaper than gasoline. However, due to ethanol’s lower energy content, ethanol’s average price per gasoline equivalent gallon was $1.07 more expensive than gasoline.
Some critics of ethanol claim that it has a negative net energy balance. Our research shows that this criticism may be not only false, but also arbitrary when considering the environmental impact of ethanol fuel. Recent studies have revealed that ethanol has a positive net energy balance. Additionally, ethanol net energy studies have calculated a noticeable uptrend in their results. The following graph displays this point:
Finally, many experts point out that while the evaluation of a fuel’s energy balance is easy to understand, the results in isolation could be arbitrary. The evidence supporting this belief is the fact that all energy BTUs are not created equal. If all BTUs were equal then we would not pay over ten times as much for electrical energy derived from coal as we do for the energy in the coal itself. All energy conversion systems lose some quantity of energy in order to increase energy quality. Gasoline from petroleum actually has a poorer net energy than ethanol from corn.
Instead of net energy balance, the complete robust way of evaluating a fuel’s effect is to compare the fuel, in this case ethanol, with those to be displaced, in this case gasoline. By using important environmental metrics such as GHG emissions and fossil fuel consumption to compare these two fuels, one can make a direct comparison as to which fuel is ultimately the more environmentally friendly option.
Fleet managers that want more information on the availability and costs of ethanol fuel on a more local level should visit the U.S. Department of Energy’s Alternative Fuels Data Center. There fleet managers can find the DOE Alternative Fueling Station Locator and the Clean Cities Alternative Fuel Price Report. Additionally, the Alternative fuel’s Data Center allows fleet managers to view their state's incentives and laws related to alternative fuel and advanced vehicle use.