Pros and Cons of Ethanol

The Upside of Ethanol

Proponents of ethanol emphasize its environmental and energy security benefits.

• Ethanol is a renewable fuel that comes from agricultural feedstocks, and thus can be produced domestically.

Using ethanol made from corn instead of gasoline would lead to a moderate 13 percent reduction in greenhouse emissions. Using cellulosic ethanol from feedstocks such as switchgrass, pictured above, could result in 88 percent less greenhouse gas emissions. (Photo: National Renewable Energy Lab.)

Using ethanol (particularly E85, a 85-percent blend of ethanol to gasoline) also results in less pollution, reducing smog-forming emissions by as much as 50 percent relative to gasoline. E85-powered vehicles also contribute to global warming, although experts disagree about just how much greenhouse gas is emitted when using ethanol.

One might expect that by using E85, net carbon dioxide emissions would be almost zero. The crops used to make the ethanol absorb CO2 from the atmosphere during their growth, and then this CO2 is put back into the atmosphere when the ethanol is burned in an automobile engine. In reality, this cycle is overly simplistic because it fails to recognize other greenhouse gas emissions that occur during the cultivation and production of ethanol. Modern farming, for example, relies heavily on diesel-powered equipment that emits greenhouse gases. Distilling ethanol is also an energy-intensive process that often uses electricity generated from coal, another source of greenhouse emissions.

Researchers at the University of California at Berkeley examined six major studies of ethanol production and concluded that using ethanol made from corn instead of gasoline would lead to a moderate 13 percent reduction in greenhouse emissions. However, the researchers note that more dramatic reductions are possible if technology advances make it economical to make ethanol from cellulosic materials such as switchgrass, a crop currently grown by some U.S. farmers to control erosion on idle fields. Using cellulosic ethanol, they project, could result in 88 percent less greenhouse gas emissions.

The UC Berkeley study also contradicts a common criticism of ethanol: that it takes more energy to produce it than it delivers as a motor fuel. The study concludes that ethanol made from corn does indeed have a positive "net energy balance," particularly if you consider that other valuable products, such as corn oil, are byproducts of the ethanol-making process.

The Downside

E85 may be better for the environment and the American farmer, but it has some drawbacks.

• The first is price: ethanol prices fluctuate on a different cycle than gasoline, meaning that ethanol is sometimes cheaper but sometimes more expensive. Past trends have E85 selling in the Midwest (where much of the country's ethanol is produced) for nearly 30 cents less per gallon than conventional gasoline. During some of those times, filling up with ethanol on the West Coast or in the mid-Atlantic states cost a driver as much as 40 cents more per gallon.
• The higher price of E85 in many areas is made worse by ethanol's second drawback: ethanol, regardless of the price you pay for it, contains less energy than gasoline. This means that your car won't go as far on a gallon of E85, and your fuel economy will decrease by 20-30 percent. This is bad news for consumers because even if the price of E85 at the pump is cheaper than gasoline, using ethanol may not be less expensive in the end.
• Another other issue is that E85 is widely available only in the Midwest. The DOE lists several hundred E85 stations in the United States, but nearly half of those are in two states: Minnesota and Illinois. Other areas, even populous ones, have little E85 infrastructure. For example, New York, California, Texas and Florida have fewer than 100 E85 public stations combined.

To put things in perspective, there are more than 180,000 stations nationwide selling gasoline. While all of them may not need to offer E85, it is clear that wider distribution is needed before E85 can begin to displace gasoline sales.

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