Development and de-risking of bio-electrochemical systems (BES's) for methanation

Shell Global Solutions current net-zero goals involve using the company’s capabilities to support the delivery of integrated energy solutions to different customer sectors. Power-II-Gas (P2G) technologies fit the purpose, by changing energy sources to renewables and contributing to a low-carbon economy. In P2G renewable energy is converted into H2 through electrolysis, which can be directly used or combined with CO2 to produce CH4 (Power-II-Methane, P2M). State-of-the-art P2M alternatives, thermo-chemical and biological methanation, make use of metal catalysts and methanogenic microorganisms respectively, for the 2-step conversion of CO2 to CH4 (electrolysis and methanation). Although both routes provide mature technologies for methanation, novel concepts are still required to allow intermittent operation at reduced cost and high energy efficiency.
Bio-electrochemical Systems (BES’s) are proposed in this work for the 1-step conversion of CO2 to CH4, using renewable energy and an open-culture of micro-organisms. In BES electrolysis and methanation take place simultaneously at the reactor, avoiding production, storage, and transport of pure H2. Avoiding separate electrolysis is expected to result in higher energy efficiency, reduced safety risks, and lower capital and operating costs in comparison to thermochemical and biological methanation. In a joint venture collaboration with Paques, Shell is working on the development and de-risking of a BES for pilot scale methane production. Several activities were completed to support the Basis of Design (BoD) of the BES pilot plant, such as plant simulation, equipment sizing, risk assessment, and techno-economic assessment. These activities allowed to conclude about the technical feasibility and economic viability of bio-electrochemical systems for methanation, where CO2 from waste industry streams is converted into pipeline quality renewable natural gas. The commercialization of this innovative P2M technology is still dependent on improving the configuration and operation of the bio-electrochemical reactor, reducing capital and operating costs, and operating BES P2M commercial plants with the energy efficiency demonstrated at lab-scale.