## 4 Results and Discussion  
### Climate Change  
Figure 4 presents the life cycle impact on climate change for the different powertrain technologies. Starting from the left-hand side, the impact of the use phase is emphasized for the ICE-based powertrains. For the plug-in hybrid, we report a similar impact than for diesel, and this is primarily due to the high real-world tank-to-wheel emissions of the former. Moving over to the EVs, an unmistakable difference gap is caused by the absence of tank-to-wheel emissions for the electric models, resulting in a lesser overall CO\({}_{2}\) impact, while well-to-tank emissions result from the average energy consumption and the characteristic CO\({}_{2}\)-intensity of the European energy mix. The fact that battery size is proportional to energy consumption is highlighted for the 90 kWh EV. Thus, it represents nearly twice the climate change impact of the 30 kWh variants. Regarding the impact of the EV + trailer combinations, the battery and the generator trailer prove to have a favorable effect when compared to the 90 kWh EV. While offering the same range as the latter, the generator trailer combination allows a 33 percent lower CO\({}_{2}\) emission. In the case of the battery-equipped trailer, this gap widens to over 40 percent. When comparing the trailer combinations to the 60 kWh EV, only a small difference is reported for both concepts. Regarding the potential for carbon savings by substituting PHEVs by a range-extender trailer that is only occasionally coupled to a 40 kWh EV, a reduction exceeding 50 percent is offered by the petrol trailer and over 58 percent in the case of the battery trailer. The results shown in Figure 4 confirm both the benefits of electric vehicles over internal combustion engine vehicles when climate change is concerned, and the energy mix as a strong determinant of the EV's well-to-tank emission profile. This energy mix could be managed intelligently if smart charging mechanisms would allow EVs to recharge only when solar and wind energy is abundant. Thus, EVs could be the intermediary solution until battery storage of renewables becomes economically viable. In the absence of smart meters, an uncontrolled grid connection of a significant EV fleet could nonetheless result in additional peak loads. Responding to this power demand using coal-fired power plants results in high CO\({}_{2}\) emissions and adversely impacts air quality. Merely allocating these excess emissions to EVs alone should be avoided as they are deemed to be part of the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Impact Category** & **Unit** & **Total** & **Trailer Assembly** & **Battery** & **Battery** & **EV** \\  & & & **Excl. Battery** & **Manufacturing** & **Operation** & **(EU Mix)** \\ \hline Climate change & gCO\({}_{2}\)-eq./km & 102.5 & 3.2 & 18.0 & 0 & 81.3 \\ \hline Human toxicity & g1,4-DB-eq./km & 36.3 & 3.5 & 31.5 & 0 & 1.27 \\ \hline Photochemical oxidant formation & gSMVOC/km & 0.62 & 0.02 & 0.05 & 0 & 0.10 \\ \hline Particulate matter formation & gPM\({}_{\text{10}}\)-eq./km & 1.16 & 0.02 & 0.07 & 0 & 0.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: LCIA of the 40 kWh EV + battery trailer. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Impact Category** & **Unit** & **Total** & **Trailer Assembly** & **Generator** & **Generator** & **EV Electricity** \\  & & **Excl. Generator** & **Manufacturing** & **Operation** & **(EU Mix)** \\ \hline Climate change & gCO\({}_{2}\)-eq./km & 109.31 & 2.12 & 3.67 & 12.66 & 90.85 \\ \hline Human toxicity & g1,4-DB-eq./km & 63.44 & 2.33 & 9.94 & 0.45 & 50.72 \\ \hline Photochemical oxidant formation & gSMVOC/km & 0.26 & 0.01 & 0.01 & 0.04 & 0.19 \\ \hline Particulate matter formation & gPM\({}_{\text{10}}\)-eq./km & 0.16 & 0.01 & 0.01 & 0.01 & 0.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: LCIA of the 40 kWh EV + generator ReX for the various impact categoriestotal load system.