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What is biobutanol?

Butanol is a 4-carbon alcohol (butyl alcohol). Biobutanol is butanol produced from biomass feedstocks. Currently, butanol's primary use is as an industrial solvent in products such as lacquers and enamels.

Biobutanol as an Alternative Fuel

Photo of a parked 1992 Buick Park Avenue four-door sedan with the St. Louis Gateway Arch in the background. On the door is painted '100% Butanol.'

A ButylFuel vehicle was driven across the United States on 100% biobutanol (Source: ButylFuel, LLC)

Like ethanol, biobutanol is a liquid alcohol fuel that can be used in today's gasoline-powered internal combustion engines. The properties of biobutanol make it highly amenable to blending with gasoline. It is also compatible with ethanol blending and can improve the blending of ethanol with gasoline. The energy content of biobutanol is 10 to 20 percent lower than that of gasoline.

Under U.S. Environmental Protection Agency (EPA) regulations, biobutanol can be blended as an oxygenate with gasoline in concentrations up to 11.5 percent by volume (i.e., the EPA considers blends of 11.5% or less biobutanol with gasoline to be "substantially similar" to pure gasoline). Blends of 85 percent or more biobutanol with gasoline are required to qualify as an EPAct alternative fuel. Biobutanol proponents claim that today's vehicles can be fueled with high concentrations of biobutanol—up to 100%—with minor or no vehicle modifications, although testing of this claim has been limited.