The United States' most important crop, corn, is grown on a massive scale. The size of the crop influences environmental health, the country's food system and diet and what fuels the nation's automobiles. This series explores corn's role in contributing to factory farmed meat and obesity, how little of the crop gets directly eaten by people and how corn got so big in the US.
For most of the twentieth century, the corn that is now used to produce ethanol mostly resulted in barrels of whisky. But as scientists began to notice the toxic legacy of lead additives to gasoline and then the noxious nature of lead's successors (like MTBE), ethanol soon became the preferred gasoline additive. That nudge to get ethanol in fuel tanks was accompanied by a big shove by Congress in 2007 that mandated how much ethanol would be required to be blended into gasoline. Now, the EPA will require 18 billion gallons of ethanol to be produced in 2016, which will add to the strain of devoting more environmental resources toward producing corn to meet these requirements.
The Need for Ethanol? Anti-Knocking
To improve combustion in engines, 'anti-knocking' agents have been added to fuel since the 1920s. The first antiknock agent was lead added to gasoline to boost the octane rating, but significant environmental and public health damage led to the phase out of lead additives in the 1970s. Other anti-knocking agents, like MTBE, can contaminate groundwater. The current rules tend to favor ethanol as the additive to improve more efficient combustion. Ethanol's status as the blend of choice began to increase the demand for corn-derived ethanol, but it was an act of Congress that made the corn-to-ethanol business go gangbusters.
In December 2007, President Bush signed into law the Energy Independence and Security Act of 2007. The bill was designed to improve fuel economy in vehicles, improve energy efficiency and save energy in buildings. Once signed into law, a renewable fuel standard was also established, mandating 4.7 billion gallons of biofuels to be blended into the fuel supply. Without any competing alternatives, it effectively established a requirement to produce corn ethanol. In 2006, less than 5 billion gallons of ethanol was produced in the US. By 2009, nearly 11 billion gallons were produced, and in 2015 that figure rose to 14.8 billion gallons.
The 2007 energy act goes further, requiring 36 billion gallons be made by 2022. The Act does say that 22 billion gallons of that total should come from cellulosic ethanol derived from products like corn stover, switchgrass and wood chips, but this method of producing ethanol currently does not exist at commercial scale. The process for cellulosic ethanol takes the feedstock material and subjects it to enzymes that convert the cellulose into sugars that can then be used to produce ethanol. Current EPA fuel standard volumes measure in the millions of gallons versus the billions of gallons required from standard ethanol.
Environmental Impacts of Ethanol
An increased market for corn ethanol may influence farmers to increase acreage devoted to corn over other crops. The supply and demand in corn markets can result in volatile corn prices, which could allow prices to spike if a particular year suffers from an extended drought. High corn prices could also drive up the price for chicken, beef, pork and other animal products that are produced in confined animal feeding operations (CAFOs). Oil and fertilizer prices, perceptions about oil dependence and greenhouse gas emissions can also influence the debate over the effects of using a food crop for fuel. But in essence, ethanol mandates compound the many environmental effects of industrial-scale corn production. These include:
- Increased use of fertilizers in the Mississippi River basin, resulting in large seasonal dead zones in the Gulf of Mexico. Nutrient runoff can also cause toxic algal blooms like the one that triggered a drinking water ban in Toledo a few years ago.
- Stress on aquifers where groundwater is used for irrigation. Thirty percent of groundwater used for irrigation in the US comes from the Ogallala Aquifer in the high plains, where a great deal of corn is grown in Nebraska and Kansas. Since 1950, about 10 percent of the water has been depleted.
- Pressure on ecosystems and biodiversity when land formerly under conservation becomes cropland. Between 2007 and 2013, Kansas lost 700,000 acres of conservation land in part due to demand for corn ethanol. (Though that trend can reverse.)
- Contribution to greenhouse gas emissions when nitrogen fertilizer enters the atmosphere as nitrogen oxide, a greenhouse gas that is 300 times stronger than carbon dioxide.
With the renewable fuel standard as law, ethanol is not going to go away anytime soon. And there is an argument to be made that since it is an effective octane booster, ethanol would still likely be the gasoline industry's preferred choice even if the standard goes away. So the environmental concerns with industrial corn production remain, but there is hope that breakthroughs in cellulosic ethanol technologies will help alleviate some of those concerns by converting marginal crops and crop residue into energy.