Implementation of a site analysis for dark fermentation as the hydrogen factory of the future

There are many developments in green hydrogen production like the increasing usage of electrolysis which accounts for 5% of the produced hydrogen worldwide, as well as the many current research in biological production methods. One of the methods that have been in consideration is the usage of microorganisms to produce hydrogen through the biological pathways of dark fermentation. It can use renewable raw materials, waste, liquid manure, or sewage water as biomass to produce a hydrogen-rich gas. Hydrogen generation with dark fermentation is a promising method because the process can be integrated into existing biogas plants across Germany to use the existing infrastructure to produce not only biogas but also hydrogen as an additional product. However, modifying the existing biogas plants is not in every case feasible or economical for the operator. In the present master thesis, a site analysis was conducted, to find the well suitable biogas plants for the integration of dark fermentation and to assess the potential of hydrogen production via dark fermentation in Germany. The site analysis was based on the databases Marktstammdatenregister, Biogas Datenbank and the Biogaspartner database. For the filtering of the suitable plants, three selection criteria were created: the first based on the commissioning dates, the second based on the power capacity and the last one based on the substrate usage of the plants. As a result, there are potentially 1 468 biogas plants and 50 biomethane plants where the implementation of dark fermentation would be viable in the upcoming halfdecade. From these plants, a respectively annual hydrogen production of 44 429 t and 4 487 t was estimated, thus together Germany has a hydrogen production potential from dark fermentation of around 50 000 t/a, which corresponds to 1.63 TWh of hydrogen per year. In conclusion, dark fermentation has the potential to cover 3% of the current hydrogen need of Germany or around 1.5% of the future hydrogen need of Germany which is expected to be 90 and 110 TWh by 2030. Additional calculations were made on the biogas plant Gröbern, to compare the implementation of dark fermentation with electrolysis. The resulting levelized cost of producing hydrogen via dark fermentation with 1.63 e/kg is lower than the production cost via electrolysis, making dark fermentation a rational choice for biogas operators wanting to use their plants for hydrogen generation. Along with this, issues related to the implementation are also included, such as the approval process of hydrogen and the explosion protection of the biogas plants as well as the explosion protection of the additional parts for the dark fermentation.