# Techno-Economic Potential of Plasma-Based CO\({}_{2}\) Splitting in Power-to-Liquid Plants
## 1 Introduction
Based on the boundary conditions, fuel costs for synthetic diesel were estimated between EUR 1.9/L and EUR 2.9/L for the year 2050, depending on the location in Europe (e.g., Germany: EUR 2.4/L). The location-dependent cost variation is due to the cost of electricity, which is expected to be higher in Northern and Central Europe than in Southern Europe. The cost of electricity consists of slightly above 60% of the costs. The considered power-to-liquid process uses hydrogen generated via electrolysis to thermo-chemically split CO\({}_{2}\) in a reverse water gas shift reaction (RWGS) at 800 to 1000 \({}^{\circ}\)C and 30 bar pressure. The efficiency of the RWGS reaction was assumed to be 83%. As an alternative to synthetic diesel, it is possible to produce other electricity-based fuels from syngas, such as methanol or dimethyl ether [11]. The results of the Concave report show that these require lower manufacturing costs than synthetic diesel. Nevertheless, the prices will be at least twice as high as fossil diesel of EUR 0.8/L in 2050 [10]. In their paper from 2016, [PERSON] et al. also showed techno-economic results for power-to-liquid plants with Fischer-Tropsch synthesis with an RWGS reaction for CO\({}_{2}\) splitting [12]. They obtain fuel costs between EUR 2.2 and EUR 2.8/L as a result, with a 60% share of electricity costs. The research initiative Energiewende im Verkehr (EiV) of the German Ministry for Economy and Climate Protection (BMWK) deals with the use of electricity-based fuels. More than 100 research groups that deal with alternative fuels for large transport volumes and distances are being funded [13]. The results of the research groups should promote the coupling of the electricity and transport sectors and enable a reduction in greenhouse gas emissions. The individual joint projects are networked via the accompanying research on the energy transition in transport (BEniVer) of the German Aerospace Center (DLR). Its focus is on the consideration of technical, economic, ecological, and social effects. A standardized method for determining the production costs is being used to compare the individual fuel production processes. The PlasmaFuel joint project (2018-2022) in EiV, which includes the Institute for Photovoltaics (_ipv_) at the University of Stuttgart, dealt with the plasma-induced production of fuel for shipping. In a PtL process using electricity from renewable energies, plasma-induced CO\({}_{2}\) splitting is linked to fuel production via the Fischer-Tropsch synthesis (FTS), as shown in Figure 1. In this project, the plasma-based splitting of CO\({}_{2}\) into carbon monoxide (CO) and oxygen (O\({}_{2}\)) through a dielectric barrier discharge (DBD) and a variation of a gliding arc discharge (GA) was carried out. Through subsequent oxygen separation, the CO was synthesized together with electrolysis-H\({}_{2}\) in a Fischer-Tropsch reactor to form marine diesel. The energy required for this was supplied by excess wind power. The Smart Freight Centre and the European Chemical Industry Council provide average values of transport CO\({}_{2}\) emissions (g CO\({}_{2}\) per t km) for chemical-pharmaceutical industry transports [14]. The values for road transport are 71, for rail transport 19, for inland waterway ships 25, for ocean-going ships only about 4, and for airplanes 1060 g\({}_{\text{CO2}}\)/tkm. Due to very high loading capacities and comparatively low CO\({}_{2}\) emissions, large-scale transports by container ship cannot be replaced. The generation of electricity-based marine diesel is an important area of development for several reasons. On the one hand, the electrification of shipping is not feasible. The reasons for this are the high costs and excessive mass of the battery units needed, based on their low energy densities and the charging infrastructure. In the following case example, the problem is taken up again.