Wind and solar power generation will continue to grow in the energy supply of the future, but its inherent variability (intermittency) requires appropriate energy systems for storing and using power. Storage of possibly temporary excess of power as methane from hydrogen gas and carbon dioxide is a promising option. With electrolysis hydrogen gas can be generated from (renewable) power. The combination of such hydrogen with carbon dioxide results in the energy carrier methane that can be handled well and may may serve as carbon feedstock of the future. Biogas from biomass delivers both methane and carbon dioxide. Anaerobic microorganisms can make additional methane from hydrogen and carbon dioxide in a biomethanation process that compares favourably with its chemical counterpart. Biomethanation for renewable power storage and use makes appropriate use of the existing infrastructure and knowledge base for natural gas. Addition of hydrogen to a dedicated biogas reactor after fermentation optimizes the biomethanation conditions and gives maximum flexibility. The low water solubility of hydrogen gas limits the methane production rate. The use of hollow fibers, nano-bubbles or better-tailored methane-forming microorganisms may overcome this bottleneck. Analyses of patent applications on biomethanation suggest a lot of freedom to operate. Assessment of biomethanation for economic feasibility and environmental value is extremely challenging and will require future data and experiences. Currently biomethanation is not yet economically feasible, but this may be different in the energy systems of the near future.
Carbon dioxide (CO2) is the final waste product for all carbon-containing products. Its reuse will partly mitigate climate change and, in addition, provide a valuable feedstock for fuels and chemicals. Zuyd University of Applied Sciences (ZUYD), Innosyn B.V., and Chemtrix B.V. will develop a flow reactor for photochemical reactions with gases conducted at high pressure. This reactor is the necessary first development towards artificial photosynthesis: the connection of hydrogen (H2) to the ultimate waste product CO2 to store energy in a chemical bond, in order to produce so-called solar fuels and C1-chemicals/products. With an increasing amount of renewables in the energy system, energy storage becomes increasingly important to continuously match supply and demand. In a cooperation between three ZUYD research groups with Chemtrix B.V. and Innosyn B.V., multiple cost-efficient reactor designs for this flow reactor will be analyzed and two designs will be selected to be implemented by small extensions of existing equipment. Simultaneously, two appropriate test re-actions involving a gas (E-Z isomerization followed by hydrogenation) and with a CO2 analogue (a hydrogenation of a carboxylic acid) will be developed to be conducted in the reactor when the con-struction has been finished. We aim to disseminate the new capabilities developed in this KIEM proposal by the project partners with respect to the new reactors to several selected stakeholders. Furthermore, to expand the project several options (SIA-RAAK and H2020 grants) will be explored.
