Power-to-gas aims to provide technologies for the energy future that are capable of storing renewable energies in the gas grid cost-effectively and efficiently for a longer period of time, while at the same time driving a transition to a climate-neutral gas grid. An already established process would be the catalytic methanation, but with reaction temperatures ranging between 200 to 400°C, a lot of energy would be lost for heating. Additionally expensive metal catalysts must be used and later recovered, which can be expensive and time consuming. The focus is shifting to biological methanation using archaea. In this process,methanation takes place at comparatively low temperatures of 50 to 60°C. Figure 1 shows the theoretical efficiency of the system, by producing biogas through a fermenter and hydrogen through electrolysis.