Among the renewable liquid fuels, alcohols have been extremely popular and are widely used alternative fuel in CI engines. Alcohols can be produced in most parts of the world from selected biomass, including agriculture residues. Energy crops such as potato, sweet sorghum etc are potential sources of ethanol production. The physical and thermodynamic characteristics of alcohol do not make them particularly suitable for fuel for CI engines, but they offer a means of reducing exhaust emission of sulphur compounds, smoke, particulate matter and NOx. Ethanol improves the octane number and has a higher volumetric efficiency leading to increased power and has advantages of wider flammability limits and higher flame velocity.