One of the main interests of biofuels from an environmental point of view lies in their potentially favorable CO2 balance. Thanks to their renewable nature indeed, biodiesel and bioethanol make it possible to significantly reduce CO2 emissions throughout the entire life-cycle.
According to the European Commission data , the potential for reducing greenhouse gases (GHG) emissions is about 2,0-2,5 kg CO2 eq. per liter of biodiesel or bioethanol. In his explanatory report on the mineral oil taxation law amendment , the Federal Department of Finance mentions (and uses in its calculations) a value of 2.6 kg CO2/l for biodiesel and 2.3 kg CO2/l for bioethanol. Various studies by the Laboratory of Energy Systems (LASEN) of the EPFL  and from the literature  also indicate very similar figures. It should be noted however that these figures are generally related to the specific context of biofuels production and use.
In practice, this potential will depend on the production and use of biofuels, therefore on the raw material used to produce the fuels, transport distances for the supply and distribution of biofuels, etc. More specific evaluation is required to evaluate the actual benefits in terms of GHG emissions reduction.
Calculator of the Biofuels Platform
The Biofuels Platform proposes a calculator to evaluate the environmental impact of biofuels, according to the production pathway and the type of vehicles and fuels blends. The methods selected for the evaluation of environmental impacts are the consumption of non renewable primary energy (expressed in MJp according to the CED method) and the emissions of greenhouse gases (expressed in kg CO2 according to the IPCC method).