The Pros and Cons of Ethanol

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Ethanol—an alcohol biofuel distilled after extracting sugar from a plant such as corn or sugarcane—has triggered a great debate over its usefulness. Although this fuel burns cleaner than gasoline, it also has drawbacks, such as potential higher prices for food.

Most gasoline sold in the U.S. contains some percentage of ethanol, usually not more than 10%. According to the Energy Information Administration, the estimated 142.86 billion gallons of gasoline consumed in the U.S. in 2018 contained about 14.38 billion gallons of ethanol.

Ethanol Production and Uses

Most ethanol made in the U.S. is produced from corn. In Brazil, the second-largest producer, it's usually made from sugarcane. Other possible feedstocks are sugar beets, sorghum, switchgrass, and agricultural and forestry residues.

Ethanol makers may burn coal, natural gas, or corn or cane plant waste to generate the heat that's necessary for the production process.

If corn-derived ethanol is made in the more common process known as dry milling, a sludgy, protein-rich byproduct known as distiller's dried grains and solubles is created that makes a nutritious feed for animals—thus getting another use out of the corn.

If it's made using the process called wet milling, there are three byproducts that have other uses:

  1. A corn gluten meal that is used in pet foods and also as an herbicide.
  2. A dilute sulfuric acid solution that is used as an animal feed ingredient and also as an alternative to salt as a deicer.
  3. Corn oil for cooking and producing margarine.

Pure ethanol is biodegradable, but toxic chemical denaturants are added to it to make it unsuitable for drinking. (Ethanol, aka ethyl alcohol, is the same alcohol found in alcoholic beverages.)

Emissions of Greenhouse Gases and Other Pollutants

Using corn-derived ethanol instead of gasoline results in a 34% average reduction in greenhouse gases (GHGs), according to a study conducted by researchers at Argonne National Laboratory. That calculation takes into account the carbon dioxide the corn plants took up as they grew. Other so-called life-cycle studies—which incorporate all aspects of growing the corn and producing ethanol from it—have been split, with some concluding the use of corn-derived ethanol in place of gasoline reduces GHGs and others concluding it increases GHGs.

E85, a majority-ethanol fuel that's available mostly in the Midwest, produces less carbon dioxide and carcinogenic benzene than pure gasoline when combusted, but it produces more acetaldehydes, which are suspected of being carcinogenic and contribute to ground-level ozone pollution.

Ethanol's Impact on Corn Production and Prices

In 2018, 5.6 billion bushels out of total of 14.62 billion bushels of corn produced in the U.S. were used to make ethanol. That means 38.3% of the U.S. corn crop is being devoted to a process whose main product isn't edible.

There's no consensus among economists on the impact of ethanol production on the price of corn. A working paper from researchers at the National Center for Environmental Economics, which is part of the U.S. Environmental Protection Agency, found that a billion gallon increase in ethanol production resulted in an average increase in corn prices of 2%-3%. That determination was based on a review of studies on corn ethanol production from 2008 to 2013. They also found that changes in government policy on ethanol or bad weather conditions could result in sharper increases in corn prices and suggested, again based on a review of the literature, that an increase in biofuels production will put more people at risk for hunger.

Government's Role in Ethanol's Use

As of 2012, corn-based ethanol production is no longer subsidized by the U.S. government at the rate of 45 cents a gallon. A tariff on Brazilian ethanol was removed at the same time, as Congress failed to reinstate its pro-U.S.-ethanol policies. From 1980 through 2011, an estimated $45 billion in subsidies were given to producers of corn-derived ethanol.

Nonetheless, the government still advocates for the use of ethanol. Under the Energy Independence and Security Act of 2007, by 2022, 36 billion gallons of biofuels must be blended into gasoline and other transportation fuels each year.