Production of bioethanol through fermentation using biomass as feedstock brings with it the emission of CO2. In the global balance any use or capture of that CO2 means a reduction of greenhouse gas (GHG) emissions from the production process, and it therefore improves the overall sustainability of facilities and final products. Currently CO2 is supplied to gas companies for its use in the industry or in greenhouses.

In France the plant of Vertex Bioenergy France in Lacq, supplies the carbon dioxide it produces for multiple applications (beverage carbonation, cooling and freezing), thus replacing CO2 from petrochemical units. Likewise, Biocarburantes de Castilla y León (Spain) is developing a project to capture the CO2 gas it produces during the biomass fermentations process.