## 3 Results
### Influence of Using Electricity Based on Renewable Energy in Production  
The previous analyses show that fossil kerosene was advantageous over SAFs concerning economic impacts and, to some extent, also concerning environmental impacts. The economic competitiveness of SAFs can be improved primarily through improved large-scale industrial production processes, which need to emerge over time. However, SAFs are already partially advantageous in terms of environmental impacts. The analyses show that the energy demand and the fossil source-based electricity mix were often mainly responsible for negative impacts. The use of an electricity mix based on 100% RE could lead to a further reduction in the environmental impacts of SAFs. This is investigated in the following. For this purpose, the electricity required in the fuel supply chain was replaced by an electricity mix based on 100% RE. This electricity mix was modeled based on [PERSON] et al. [75], who forecasted the electricity mix for the year 2050. The additional LCIs of the scenarios can be found in the Supplementary Material. A comparison of the environmental and economic impacts of the two scenarios is presented in Figure 6. In the following, the addition of \"-RE\" indicates energy carriers produced with renewable energy. In terms of environmental impacts, the use of an electricity mix based on 100% RE can reduce the impacts of the SAFs in six of the seven impact categories. This is exclusively due to reduced impacts in the fuel supply chain. For biokerosene from renewable energy (SMR-RE), there were only slight improvements of 1-2% in the impact categories PMF, ALO, and POF compared with biokerosene (SMR). In contrast, 16% and 24% improvements could be achieved in the impact categories CC and FRD, respectively, and even 73% in the impact category HT. Therefore, the advantageous of the use of this fuel variant increased. Concerning synthetic kerosene, it was necessary to differentiate between hydrogen production by electrolysis and SMR. Accordingly, for synthetic kerosene (SMR-RE), in the impact categories CC, FRD, PMF, ALO, and POF, only minor improvements of 0.5-8% could be achieved compared with synthetic kerosene (SMR), but this was different for HT. Here, an improvement of 22% occurred. These improvements were much more significant regarding synthetic kerosene (PEM-RE and SOEC-RE). Thus, for PMF and POF, improvements of 15-28% could be achieved, and for CC, FRD, ALO, and HT, improvements of 71-97% could be achieved. This was due to the avoidance of fossil energy sources in electricity generation. The negative environmental impacts could be significantly reduced by eliminating the extraction and processing of lignite, hard coal, and wood chips. This is particularly evident for the improvement in CC, where the energy-intensively produced synthetic kerosene is now advantageous. Here, two aspects added up: on the one hand, the low-emission hydrogen production and, on the other hand, the demand for CO\({}_{2}\) in the FTS. This led to synthetic kerosene (PEM-RE and SOEC-RE) having a 90% and 61% lower CC impact than fossil kerosene, respectively. Additionally, the use of synthetic kerosene (PEM-RE) could reduce the impact of FRD, which was 20% lower than for fossil kerosene. Only with regard to MRD, the use of an electricity mix based on 100% RE led to deterioration due to the need for raw materials to build the RE plants. These were primarily raw materials that were costly to extract and produce, such as copper and aluminum, which were key drivers of the impact category MRD. Overall, there was a deterioration reflected in the impact scores that were 4-124% higher, resulting in the disadvantageousness of SAFs for this category. The switch to an RE-based electricity mix did not affect the economic impact. This was because it was assumed that the electricity price did not change due to the switch and was accordingly identical in both scenarios.