On January 10, 2023, Association for the Promotion of Scientific-Technical Cooperation in the Raw Materials Sector e.V. (WTZ e.V.) held the third workshop of the event series "Biogas holistically thought". The third workshop focused on hydrogen production from biomass and biogas. The processes and their economic viability were discussed. The event was moderated by Prof. Dr. Hartmut Krause (TU Bergakademie Freiberg and member of the WTZ e.V. board).

At the beginning, Johannes Full (Head of the Group "Sustainable Development of Biointelligent Technologies" at the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)) opened the technical discussion with a keynote speech on the potentials of hydrogen production from plant residues. He provided insights into the field of biohydrogen and HyBECCS (Hydrogen Bio Energy with Carbon Capture and Storage). The use of HyBECCS would allow negative emissions in the production of hydrogen. Greenhouse gas emissions reductions are not being pursued quickly and efficiently enough, so carbon dioxide removal (CDR) is now the scientific consensus as a measure to meet climate and environmental goals. In biohydrogen production, the resulting CO2 is stored for the long term. The high-purity CO2 can also be used as an end product for various applications. Technically, production is possible using biogas steam reforming or dark fermentation - a biotechnological process.

Kathrin Bienert (Head of Research and Development at VNG AG) then presented the BioHydroGen project - a BMWK-funded project that is developing a hydrogen generator for biogas in collaboration with TU Freiberg. The aim of the project, she said, is to develop a compact reforming unit to convert raw biogas into hydrogen at a biogas plant near Gordemitz. Preliminary studies will be conducted in the first phase of the project before a demonstrator is developed and built in the second phase. Ultimately, the hydrogen produced in this project will be used primarily in the mobility sector.

Finally, Dr. Caroline Autenrieth (Project Coordinator at the Institute of Biomaterials and Biomolecular Systems at the University of Stuttgart) presented hydrogen production from residual and waste materials using dark photosynthesis. All photosynthetic microorganisms can produce hydrogen, for example purple bacteria, Autenrieth explains. Such photosynthetic microorganisms form an extensive system of inner membranes in which photosynthesis takes place. Photosynthetic hydrogen production with purple bacteria requires a lot of light, which is one of the biggest challenges. In addition, aspects such as ventilation, hydrogen impermeability and explosion hazards must be considered. A pilot project is testing the production of hydrogen by dark photosynthesis at a local juice producer using fruit and vegetable residues as feedstock.