Catalytic and microbial methanation as the basis for sustainable energy storage

As the share of intermittent renewable energy—particularly from photovoltaic and wind power plants—continues to grow, energy storage systems will become increasingly important for maintaining the quality and security of the power supply in Germany. In this context, the efficient use of hydrogen will play a particularly important role. Catalytic and microbial methanation methods represent promising approaches for converting renewable hydrogen and carbon dioxide into methane and subsequently storing it in underground formations, such as existing gas storage facilities. The project therefore investigates the fundamentals of both conversion processes through experiments combined with numerical modeling and simulation to compare their technical challenges and respective energy balances.
The Institute of Subsurface Energy Systems investigates the fundamental microbial behavior in porous structures to assess the risks and potential of the methanation process. Initially, the microbial growth of methane-producing organisms (methanogenic archaea) was stimulated in batch experiments to ensure functional population growth as a baseline and to test the microscopic analysis. Samples of the microbial populations from the batch experiments were injected into a micro-model at regular intervals and analyzed. The initial image and pressure analyses show strong growth within the first few days, as seen in Figure 2. To further promote growth, the nutrient in the form of a hydrogen/carbon dioxide mixture was replenished daily. Biofilm formation has not yet been observed at this time. This can be explained by the fact that the microbes initially grew in a bottle reactor and were only subsequently injected into the porous structure