Bioelectrochemical conversion of CO2 emissions as greenhouse gases capture and renewable electricity storage strategy: advancing power-to-methane technologies − a critical review

Electromethanogenesis is an innovative bioelectrochemical process that is rapidly gaining attention within the energy transition framework as one of the most promising Power-to-Gas (P2G) technologies. This process enables the conversion of electricity generated from intermittent renewable sources, along with carbon dioxide emissions, into high-purity methane through the metabolic activity of methanogenic Archaea. Its potential is further amplified by its compatibility with existing infrastructure for methane storage, distribution, and utilization, making it a highly attractive solution for renewable energy storage and greenhouse gas reduction. This review critically examines recent advancements in electromethanogenesis, placing particular emphasis on identifying viable CO2 sources. Among these, geothermal emissions from natural gas vents are highlighted as a key opportunity for “geothermal electromethanogenesis,” while industrial off-gases are explored for their potential to mitigate environmental impact by reducing greenhouse gas emissions and producing sustainable “green” methane. Moreover, the review underscores the need for further development of sustainable and low-cost materials for electrodes and chamber separator to enhance the economic and environmental feasibility of this process. It delves into the microbial metabolic pathways, inoculum, and operational conditions that underpin electromethanogenesis, addressing the critical challenges of upscaling from laboratory-scale research to large-scale, real-world applications.