Fermentative high-pressure methanation of hydrogen

The further expansion of renewable energies will require additional power storage and transportation capacities. Using efficient vector technologies (so called power-to-gas technologies) to interlink power grids and the natural gas network very powerful transmission- and storage systems for surplus electric energy can be opened.

For this reason, fermentative high-pressure methanation as a power-to-gas concept will be investigated in this project. Carbon dioxide and hydrogen produced by electrolysis with renewable electricity are converted into methane microbiologically. This "biomethane" can then be fed into the existing natural gas grid where it is stored, transported, and used very flexibly through on-demand reconversion back into electricity or as fuel for transportation. A new concept, trickle bed reactors, will be evaluated for methanation, which promises significant advantages over alternative methods. The fixed bed allows extensive contact between microorganisms and gases, and the increased reaction pressure of up to 10 bar improves problematic gas solubility. As a result, high gas and methane yields are expected with this concept, resulting in an efficient and economic methanation production system.

To study this process, a laboratory-scale facility is planned to be built, operated, and equipped with additional measuring and control technology. Test series to investigate and optimize methane yield through operating parameters such as loading rate, retention time, pressure, and temperature will be carried out. After finding optimum operating parameters a concept will finally be developed for a large-scale plant.