Biobutanol is a 4-carbon alcohol (butyl alcohol) produced from the same feedstocks as ethanol including corn, sugar beets, and other biomass feedstocks. Butanol is generally used as an industrial solvent in products such as lacquers and enamels, but it also can be blended with other fuels for use in conventional gasoline vehicles. Iso-butanol is the only form of butanol that is being used as a fuel (the others are tert-butanol and n-butanol). Biobutanol can be used to oxygenate and blend with gasoline in concentrations up to 16% by volume. At 16% butanol, the oxygenated content in the gasoline would be the same as a 10% ethanol blend. Similar to methanol and ethanol, biobutanol blends of 85% or more with gasoline are considered alternative fuels under the Energy Policy Act of 1992. Underwriters Laboratory allows the dispensing of biobutanol blends in equipment listed under UL 87A for ethanol blends above E10.
Producing biobutanol via fermentation has been possible since the early 1900s but is currently more expensive than producing petrochemicals. Modern butanol is produced almost entirely from petroleum. Renewed interest in biobutanol as a sustainable vehicle fuel has spurred technological advances to ferment biobutanol. The first commercial-scale facilities are expected to be former ethanol corn plants converted to biobutanol corn plants.
Biobutanol offers an alternative to conventional transportation fuels. The benefits of biobutanol include:
- Higher Energy Content—Biobutanol's energy density is only 10% to 20% lower than gasoline's.
- Increased Energy Security—Biobutanol can be produced domestically from a variety of feedstocks, while creating U.S. jobs.
- Fewer Emissions—Carbon dioxide captured by growing feedstocks reduces overall greenhouse gas emissions by balancing carbon dioxide released from burning biobutanol.
Research and Development
The U.S. Department of Agriculture's (USDA) Agricultural Research Service is studying biobutanol production. The U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA) are funding biobutanol research and development as part of their Small Business Technology Transfer and Small Business Innovation Research programs.
Learn more about methanol from the links below. The Alternative Fuel Data Center (AFDC) and DOE do not necessarily recommend or endorse these companies (see disclaimer).
- Argonne National Laboratory
- Impact of Higher Alcohols Blended in Gasoline on Light-Duty Vehicle Exhaust Emissions
- Biobutanol (Green Car Congress)
- Opportunities in the Industrial Biobased Products Industry (DOE Bioenergy Technologies Office)
- Production of Butyric Acid and Butanol from Biomass: Final Report
- USDA Agricultural Research Service:
- Cost-Effective Bioprocess Technologies for Production of Biofuels from Lignocellulosic Biomass
- Advanced Conversion Technologies for Sugars and Biofuels: Superior Feedstocks, Pretreatments, Inhibitor Removal, and Enzymes
- Mixed Community Bioreactors to Convert Lignocellulosic Feedstocks into the Liquid Biofuel Butanol
- Improving Biochemical Processes for the Production of Sustainable Fuels and Chemicals