From field to tank - comparison with petrol

Carbon cycle

The emission of greenhouse gases associated with the production of bioethanol, and the combustion of the bioethanol component of biofuels, are offset by the carbon fixed by plants during their growth (photosynthesis). However, the overall result does not entirely balance out, since the production and supply of energy and feedstocks used in the conversion of biomass, generate carbon dioxide emissions that are often of fossil origin.
Indeed, the agricultural production methods (machinery, fertilizer, phytosanitary products, etc.), the choice of conversion processes (energy optimisation, recycling energy from waste, etc.) the type of transport and market proximity all determine the overall CO2 impact of the production chain.
Responsible production chains can achieve a 50% reduction in CO2 emissions compared with petrol, while those geared towards reducing CO2 emissions can achieve over 80% reduction.

Fossil fuel requirements and CO2 emissions

The amount of fossil fuel (crude oil) required to produce a litre of ethanol compared with a litre of petrol, and the CO2 emissions of each of these fuels is very different:

• 1.36 litres of crude oil is required to produce 1 litre of petrol, compared to 0.33 of a litre to produce 1 litre of ethanol (lignocellulosic). 
  
• the production and combustion phases of a litre of petrol generate 3 kg of CO2eq, compared with 0.6 kg for a litre of ethanol (from field to pump).