Alcohol has been promoted and used as a motor fuel for more than 50 years. However, United States ethyl alcohol production is small compared with gasoline production.
High latent heat of vaporization of alcohol makes possible some increase of power over gasoline. The heating value of alcohol is low and energy content of alcohol blends is less than that of gasoline; fuel consumption of blends is therefore increased.
The ability of ethanol to improve the octane number of gasoline has diminished as the octane number of gasoline has improved.
There is no published evidence that alcohols can appreciably reduce air pollution problems.