Hydrogen produced via electrolysis can be synthetically converted into methane. This concept falls under the broader term "Power to Gas." Methane has a significantly higher volumetric energy density than hydrogen. This synthetically produced methane can be fed into the natural gas grid, which is only possible to a limited extent with hydrogen. Besides hydrogen, a carbon dioxide source is needed. Depending on the process technology, the CO₂-H₂ mixture can either be directly converted into methane in the methanation process, or a prior reduction of CO₂ to carbon monoxide (CO) is required. The latter occurs at very high temperatures >500°C and requires additional energy. The methanation process itself is exothermic (i.e., heat is released during the reaction, leading to thermodynamically unavoidable losses) and requires increased process pressures. To achieve practical yields in methanation, catalysts, typically based on nickel (Ni) as the active component, are required. The reaction then takes place within a typical temperature range of 250 to 650°C and pressures between 1 and 80 bar (Kaltschmitt 2024). For applications in the mobility sector, methane could be directly used in gas-powered vehicles.