Federal law sets a minimum annual level of biofuel production
The Renewable Fuel Standard (RFS) sets annual targets both for total biofuel production through 2022 (36 billion gallons in that year), and for the fraction of that total that must be “advanced” biofuels.[[see the Energy Policy Act of 2005 (PDF) by the One Hundred Ninth Congress of the United States of America.]] [[see the Energy Independence and Security Act of 2007 (PDF) by the One Hundred Tenth Congress of the United States of America.]] Biofuels are fuels made from crops such as corn, or from other biomass — typically plant material, such as woodchips. Because corn is by far the most common raw material today for non-advanced biofuels, the RFS amounts to a mandate for continued increase in corn ethanol production for the next several years. This graphic shows the effective mandate for corn ethanol — the difference between total and “advanced” biofuels.
About a third of America’s corn crop is converted to ethanol today, with Iowa as the nation’s leading producer. While supporters have argued that using corn ethanol reduces greenhouse gas emissions compared to gasoline, the energy required to make corn ethanol and the potential land use changes from increased corn farming, at home and abroad, call this claim into question. Some “advanced” biofuels such as cellulosic ethanol generally appear to offer a better climate equation.