Corn Ethanol - Environmental and Social Issues

Environmental and Social Issues

See also: Environmental and social impacts of ethanol fuel in the U.S.

Since most U.S. ethanol is produced from corn and the required electricity from many distilleries comes mainly from coal plants, there has been considerable debate on the sustainability of corn-based bio-ethanol in replacing fossil fuels. Controversy and concerns relate to the large amount of arable land required for crops and its impact on grain supply, direct and indirect land use change effects, as well as issues regarding its energy balance and carbon intensity considering the full life cycle of ethanol production, and also issues regarding water use and pollution due to the increase expansion of ethanol production.

The initial assumption that biofuels were good for the environment because they had a smaller carbon footprint is in debate over the contention that the production of grain alcohol, and therefore E85, may actually have a greater environmental impact than fossil fuel.

That view says that one must consider:

• The impact of fertilizers and carbon requiring inputs vs carbon offsetting byproducts like distillers grains.
• The carbon footprint of the agricultural machinery run to plant, harvest and apply chemicals.
• The environmental impact of those chemicals themselves, including fertilizers and pesticides necessary for efficient mass-production of the grains used.
• The larger amount of energy required to ship and process the grains and turn them into alcohol, versus the more efficient process of converting oil into gasoline or diesel.
• Even resources such as water, needed in huge amounts for grain production, can have serious environmental impact, including ground water depletion, pollution runoff, and algae blooms from waste runoff.

The U.S. Department of Energy has published facts stating that current corn-based ethanol results in a 19% reduction in greenhouse gases, and is better for the environment than other gasoline additives such as MTBE.

Ethanol produced today results in fewer greenhouse gas (GHG) emissions than gasoline and is fully biodegradable, unlike some fuel additives.

• Today, on a life cycle basis, ethanol produced from corn results in about a 20 percent reduction in GHG emissions relative to gasoline. With improved efficiency and use of renewable energy, this reduction could be as much as 52 percent.
• In the future, ethanol produced from cellulose has the potential to cut life cycle GHG emissions by up to 86 percent relative to gasoline.
• Ethanol blended fuels currently in the market – whether E10 or E85 – meet stringent tailpipe emission standards.
• Ethanol readily biodegrades without harm to the environment, and is a safe, high-performance replacement for fuel additives such as MTBE.

Others say that ethanol from corn, as a fuel available now, and cellulosic ethanol in the future, are both much better fuels for the environment. Ethanol derived from sugar-beet as used in Europe or sugar-cane as grown in Brazil in industrial scale is generally seen as having a very positive CO₂ balance with up to 80% reduction in well-to-wheel CO₂.

A University of Nebraska study in 2009 showed corn ethanol directly emits 51% less greenhouse gas than gasoline. However this study does not take into account the greenhouse gasses involved in production and transportation