Experimental investigation and energy considerations on hydrate-based biogas upgrading with CO2 valorization

Energy evaluations, carried out comparing three different scenarios (utilization of the raw biogas, utilization of the upgraded biogas, utilization of the upgraded biogas and the methane obtained through the methanation of the separated CO2) and considering the energy costs of the three processes, demonstrate that the energy content increase is equal to 22.1% in case of hydrate-based upgrading and 42.0% in case of the integration of the upgrading process and the CO2 methanation. If the electrolysis is considered as an energy cost of the integrated process with CO2 methanation, the energy benefit is just 0.1%. Nevertheless, if hydrogen is produced from renewables, balancing, security and matching issues in the energy systems as well as the CO2 emissions mitigation needs are addressed.