The system studied in this chapter as for illustration is concerned with the production, dis­tribution and use (WtW approach) of anhydrous fuel-bioethanol (99.7% wt.) as a transport fuel in Switzerland. Bioethanol is supposed to be produced from wheat also grown in Switzerland. The functional unit is 1 km.

The LCI is established by means of a spreadsheet model developed by ENERS Energy Concept and the Bioenergy and Energy Planning Research Group (BPE) of the Swiss Federal Institute of Technology, Lausanne (EPFL). The model is based on Microsoft® Excel and integrates the ecoinvent v2 database (ecoinvent, 2007; Frischknecht, 2004; Frischknecht et al., 2004), a reference in the field of LCA, developed by the Swiss Centre for Life-Cycle Inventories. The model is based on industrial data from the EU provided by the Swiss Alcohol Board, and was actually used in the implementation of various bioenergy datasets in the ecoinvent v2.0 database (Jungbluth et al., 2007; Nemecek and Kagi, 2007). The model reports on the consumption of resources (energy, chemicals, land, water, infrastructures) and emissions all along the production chain. The model was implemented in order to offer an extensive set of options regarding methodological choices.

The LCA carried out in this chapter complies with the ISO standard on LCA (ISO, 2006a, b). GHG emissions were assessed using the IPCC Global Warming Potentials (GWPs) with a time frame of 100 years. This method is most commonly used in the literature when dealing with global warming. The main greenhouse gases taken into account are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), with respective global warming potentials (GWP) of 1, 23, and 296. Because biogenic CO2 captured by photosynthesis during plant growth is eventually almost totally emitted as CO2 during bioethanol production (fermenta­tion) and utilization (combustion), only fossil CO2 emissions are taken into account. Direct field emissions of N2O are based on a model by Agroscope (Nemecek and Kagi, 2007), also included in the ecoinvent database.