*Article* **A Techno-Economic Assessment of Fischer–Tropsch Fuels Based on Syngas from Co-Electrolysis**

**Ralf Peters 1,\*, Nils Wegener 1,2, Remzi Can Samsun 1, Felix Schorn 1,3, Julia Riese 2, Marcus Grünewald <sup>2</sup> and Detlef Stolten 3,4**


**Abstract:** As a part of the worldwide efforts to substantially reduce CO2 emissions, power-to-fuel technologies offer a promising path to make the transport sector CO2-free, complementing the electrification of vehicles. This study focused on the coupling of Fischer–Tropsch synthesis for the production of synthetic diesel and kerosene with a high-temperature electrolysis unit. For this purpose, a process model was set up consisting of several modules including a high-temperature co-electrolyzer and a steam electrolyzer, both of which were based on solid oxide electrolysis cell technology, Fischer–Tropsch synthesis, a hydrocracker, and a carrier steam distillation. The integration of the fuel synthesis reduced the electrical energy demand of the co-electrolysis process by more than 20%. The results from the process simulations indicated a power-to-fuel efficiency that varied between 46% and 67%, with a decisive share of the energy consumption of the co-electrolysis process within the energy balance. Moreover, the utilization of excess heat can substantially to completely cover the energy demand for CO2 separation. The economic analysis suggests production costs of 1.85 €/lDE for the base case and the potential to cut the costs to 0.94 €/lDE in the best case scenario. These results underline the huge potential of the developed power-to-fuel technology.

**Keywords:** CO2 electrolysis; co-electrolysis; electrofuels; power-to-fuel; power-to-liquid; solid oxide electrolysis; synthetic diesel; synthetic kerosene; water electrolysis
