Environmental and Energy Consequences of Using Corn Ethanol as a Biofuel

Corn ethanol is viewed by many supporters as a sustainable fuel that can replace gasoline, reduce greenhouse gas emissions relative to fossil fuels, and increase energy security. Unfortunately, these claims are not supported by production practices. Corn ethanol is more expensive than gasoline. Its production and use results in higher carbon emissions than gasoline and causes additional environmental concerns such as eutrophication, soil erosion, land use change, and air and water pollution. The net energy from ethanol—be it positive or negative—almost certainly provides less than the minimum surplus required to support our present industrial society. Separately, high cost, negative environmental impacts, and insufficient energy return, could each prevent corn ethanol from being a sustainable fuel; taken together, corn ethanol certainly should not be blended with gasoline. Nonetheless, under the current renewable fuels standard, corn ethanol is a required additive and its use will continue for the foreseeable future.