XEL2Gas – excess electricity to biogas

The XEL2Gas project aims at developing a smart, integrated, and robust biorefinery concept for long-term storage of surplus renewable electricity in the form of acetic acid. The energy storage concept we propose involves biological conversion of hydrogen and carbon dioxide into acetic acid, which can be either stored or used as booster for biogas production. Efficient conversion of electrolytically produced hydrogen into acetic acid and biogas can accommodate a significant amount of excess and fluctuating electricity, thus counterbalancing the unfavorable economy of peak production which is characteristic for contemporary wind and solar energy production. To ensure the lowest costs of converting surplus renewable electricity into acetic acid, we propose to integrate the processes with excess CO2 production from a biogas plant, which will add substantial benefits for the biogas plant, thereby increasing its economic viability. The biological conversion of hydrogen and carbon dioxide into acetic acid will be performed in a novel process using tailored microorganisms in an innovative modular bioreactor. The use of acetic acid as instant booster of biogas production will further contribute to place biogas production as key technology for balancing fluctuating renewable energy production in the future.