Carbon dioxide emissions from vehicles fuelled with ethanol mixtures

The growing interest in the possible use of ethanol from natural sources to blend with petrol (gasoline) derived from crude oil (or synthesis from other fossil fuels) should be supported by knowledge of the likely effect on greenhouse gas emissions. This contribution estimates the emission of CO2 from petrolethanol blends as a function of the volume percentage ethanol in the blend and the consumption of petrol/100km in the average vehicle. The effect of the ethanol having a lower energy per unit mass or volume than petrol is specifically taken into account.