Novel material-oriented valorization of biogas can achieve more carbon reduction than traditional utilization by bioelectricity or biomethane.

ABSTRACT

Two novel biogas upgrading strategies that recover high-value chemicals or CO2 liquid fertilizer from biogas besides biomethane were evaluated from the view of global warming potential (GWP) through life cycle assessment in comparison with conventional approaches. Results show that the scenarios producing biomethane with nano calcium carbonate or CO2 liquid fertilizer from biogas present significantly lower GWP (-3.4 kgCO2-eq/Nm3-biogas and -4.4 kgCO2-eq/Nm3-biogas, respectively), compared to combined heat and power scenario (-2.4 kgCO2-eq/Nm3-biogas) and biogas upgrading by high pressure water scrubbing scenario (-1.3 kgCO2-eq/Nm3-biogas). The carbon sequestration and utilization from CO2-rich water significantly enhanced carbon reduction in overall biogas management. Furthermore, considering cleaner electricity in the future, strategies focusing on managing biogas for materials will align more with climate change goals than energy-focused strategies. This study provides insight for decision-makers in developing roadmaps for carbon reduction pathways in biogas-relating sectors.