Bio-ethanol is produced from plants such as maize, wheat, sugarbeet and sugarcane, through a process of fermentation, distillation and dehydration. Brazil is currently the world’s largest producer, with almost half of all fuel used in Brazilian cars being bio-ethanol.

It can be used as a 5% blend with petrol in unmodified engines, but higher blends or use as a direct substitute for petrol require some engine modifications.

Biobutanol

This is another alternative to petrol, and is produced from biomass in a similar way to bio-ethanol but with a modified fermentation and distillation process.

Biobutanol has some advantages to bio-ethanol as it can be used as higher blends without engine modification, and can be blended with diesel as well as petrol. It can also be distributed more easily by pipeline as it mixes less easily with water.