Hybrid vehicles by nature achieve greater fuel efficiency and thus emit fewer greenhouse gases per mile. Internal combustion engines operating on ethanol also produce fewer greenhouse gas missions since ethanol is less carbon-rich than gasoline. Combine the two and you have a powerful approach for reducing greenhouse gas emissions in any vehicle. About 10% of gasoline sold in the U.S. is a blend of up to 10% ethanol, an alcohol that's made by distilling corn, wheat, and sugar.
Ethanol fuel is ethanol - the same type of alcohol found in alcoholic beverages. It can be used as a fuel, mainly as a biofuel alternative to gasoline, and is widely used by flex-fuel light vehicles in Brazil, and as an oxygenate to gasoline in the United States. Because it is easy to manufacture and process and can be made from very common crops such as sugar cane and corn, in several countries ethanol fuel is increasingly being blended as gasohol or used as an oxygenate in gasoline. Bioethanol, unlike petroleum, is a renewable resource that can be produced from agricultural feedstock.
Ethanol is most commonly used to power automobiles, though it may be used to power other vehicles, such as farm tractors and airplanes. Ethanol (E100) consumption in an engine is approximately 51% higher than for gasoline since the energy per unit volume of ethanol is 34% lower than for gasoline. In general, ethanol-only engines are tuned to give slightly better power and torque output than gasoline-powered engines. When ethanol fuel availability allows high-compression ethanol-only vehicles to be practical, the fuel efficiency of such engines should be equal or greater than current gasoline engines.