## 3 Results  
### Overview of Impact Assessment Results  
An overview of the environmental and economic assessment results is provided in Table 3. The lowest scores in each impact category are highlighted in bold. As described in Section 2.3, the use of the four SAFs compared to fossil kerosene was investigated on a medium-haul flight of 2000 km. The assessment results are presented concerning the functional unit of 100 pkm.  
The aggregated results show that deployment of the investigated SAFs instead of fossil kerosene could reduce some of the environmental impact scores (CC, FRD, and HT) but was also associated with higher environmental impacts in other categories (PMF, ALO, POF, and MRD) as well as substantially higher LC.  
Overall, the analysis of the environmental impact categories shows that the use of SAFs would be advantageous, especially regarding the reduction of climate-damaging and health-damaging emissions, but fossil kerosene could also be advantageous over SAFs due to their higher impact scores in other impact categories. For example, the high impact scores regarding ALO can be explained by the demand for land to cultivate the feedstock for biokerosene and the extraction, processing, and final conversion of lignite, hard coal, and wood chips to electricity, of which a high amount is required to produce synthetic kerosene (PEM and SOEC).  
Concerning the economic impact of LC, it is evident that SAFs cannot yet achieve market penetration. The use of synthetic kerosene (PEM and SOEC) results in particularly high LC which exceed those of fossil kerosene by 786% and 588%, respectively. Economically semi-competitive is the use of biokerosene (SMR) and synthetic kerosene (SMR) which,  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Dimension** & **Impact Category** & **Unit** \\ \hline \multirow{8}{*}{Environmental} & Climate change (CC) & kg CO\({}_{2}\)-eq. \\  & Fossil resource depletion (FRD) & kg Oil-eq. \\  & Particulate matter formation (PMF) & kg PM\({}_{10}\)-eq. \\  & Agricultural land occupation (ALO) & m\({}^{2}\) per year \\  & Photochemical oxidant formation (POF) & kg NMVOC-eq. \\  & Human toxicity (HT) & kg 1.4-DCB-eq. \\  & Mineral resource depletion (MRD) & kg Fe-eq. \\ \hline Economic & Life cycle costs (LC) & US-Dollar \\ \hline \hline \end{tabular}
\end{table}
Table 2: Environmental and economic impact categories.  
\begin{table}
\begin{tabular}{l l l c c c c c} \hline \hline \multirow{2}{*}{**Dimension**} & **Impact** & \multicolumn{5}{c}{**Per 100 Passenger Kilometers Traveled**} \\  & **Category** & **Unit** & **Kerosene (Fossil)** & **Kerosene (bio\_SMR)** & **Kerosene (syn\_SMR)** & **Kerosene (syn\_PEM)** & **Kerosene (syn\_SOEC)** \\ \hline \multirow{8}{*}{Environmental} & CC & kg CO\({}_{2}\)-eq. & 15.7960 & **11.9856** & 14.7195 & 57.5965 & 43.3410 \\  & FRD & kg Oil-eq. & 5.4647 & **2.0757** & 9.7122 & 19.3292 & 16.1859 \\  & PMF & kg PM\({}_{10}\)-eq. & **0.0288** & 0.0412 & 0.0539 & 0.0843 & 0.0740 \\  & ALO & m\({}^{2}\) per year & **0.1180** & 2.7944 & 0.2988 & 2.7630 & 1.9225 \\  & POF & kg NMVOC-eq. & **0.0678** & 0.0967 & 0.1221 & 0.1836 & 0.1629 \\  & HT & kg 1.4-DCB-eq. & 6.3265 & **2.3085** & 2.7208 & 58.3424 & 39.3755 \\  & MRD & kg Fe-eq. & **0.1320** & 0.1469 & 0.3564 & 0.9510 & 0.7482 \\ \hline Economic & LC & US-Dollar & **2.5905** & 7.6675 & 6.4417 & 22.9424 & 17.8238 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Environmental and economic assessment results of the aviation fuels used for flight operation regarding the functional unit of 100 pkm traveled.  
however, lead to 196% and 149% higher LC, respectively. The key drivers of environmental and economic impacts are analyzed in more detail in Sections 3.2 and 3.3.