Alternative fuels have been developed for standard spark ignition engines. The fuels, which contain generic bio components, maintain all the advantages of ethanol, that is the ability to increase considerably the octane number of gasoline and reduce the amount of harmful pollutants in the exhaust emissions of engines operating on such blends. In contrast to ethanol the new fuel components do not increase the vapour pressure of gasoline-ethanol blends, have a better tolerance to water and do not increase the fuel consumption. The bio component based fuels also compare favourably with mineral sourced octane boosters such as MTBE. Additionally reformulation of the base gasoline becomes unnecessary.