The concept and methodologies of this study is in context with
previous studies [8,37,48]. The system boundary of the three cases
studied here and the reference cases are given in Figs. 1–4. The
required data were obtained from literature, the process requirements
of the inventory were selected and then normalized for a
functional unit of 1 kg biodiesel (dry weight basis) to estimate
the GHG emission and fossil energy for well to tank (WtT). For tank
to wheel (TtW) the methodology developed in [48] was used to
estimate the fuel specific consumption and consequently the
well-to-wheel GHG emissions of the biodiesel for 1 km traveled
was calculated using Eqs. (1) and (2) where, biofuel, fuel blend
and fossil fuel represent biodiesel, biodiesel blend and fossil diesel
per km service. Fuel specific consumption is the amount of fuel
consumed by the vehicle for a specific distance traveled and blend
factor is the percentage of biofuel mix in fossil fuel. However, for