This report presents the results of experimental tests aimed at studying and optimizing electromethanogenesis processes. This innovative biotechnology uses microbial electrochemical systems to produce methane from CO2, in a power-to-gas (BEP2G) framework. During the experiments, double-chamber experimental setups were created to conduct electromethanogenesis tests under mesophilic (45°C) and hyperthermophilic (80°C) conditions. Selected hydrogenotrophic microorganism strains from the Metanobacteriaceae family (domain Archaea) were used in the experiments. The methane concentration produced with the developed setups, at 1.2 mol/m² per day (normalized to the geometric area of the cathode), shows a faradic efficiency above 80% and surpasses the best values reported in the literature. This result was achieved using high-surface-area cathodes, consisting of porous carbon multi-composites (conductive biochar) doped with copper (Cu) nanoparticles and hydroxyapatite (HAP), as innovative chemical catalysts for CO2 reduction (CO2RR). The new materials tested provided a synergistic action with the microorganisms, promoting CO2 reduction and stabilizing the electrode pH. Experiments conducted at 80°C with the hyperthermophilic hydrogen-producing bacteria Thermotoga neapolitana and methanogenic archaea Methanococcus jannashii, although not showing equally significant methane yields, demonstrated strong interaction with the electrode materials. Therefore, the use of these bacteria and the tested sustainable materials confirms an efficient and innovative path for scaling up bioelectrochemical electromethanogenesis technology to competitive costs for future industrial and environmental applications..