Ethanol Use in the United States: Status, Threats and the Potential Future

Biofuel refers to liquid, solid and gaseous fuels produced from biomass, though this chapter focuses only on liquid biofuels. This review covers the status of biofuels in the United States, in respect to legislative mandates at both the state and national levels (Energy Independence and Security Act mandated Renewable Fuels Standard and the California Low Carbon Fuels Standard) and changes in the market, in technology development, in the economic impacts of the introduction of these fuels, and in response to nascent regulations (eg, Corporate Average Fuel Economy standards), all of which shape the industry today. The chapter addresses many of the obstacles to increased ethanol use in a system where vehicle technology is changing relatively rapidly compared to the past and new fossil resources are being discovered and rapidly developed. Costs of production for corn and cellulosic ethanol, algal-based fuels, and butanol, along with a comparison of their greenhouse gas emissions profiles are discussed.