Improvement of substrate turnover through integrating dark fermentation into existing biogas plants

Abstract

The decarbonization potential of hydrogen offers increasing usage paths in the fight against climate change resulting in a growing demand for climate‐neutral hydrogen. This challenge is met by producing hydrogen microbially from renewable substrates as an alternative to ‘green hydrogen’ from water electrolysis. Initial results have shown that coupling dark fermentation and anaerobic digestion is not only possible but also advantageous. Specifically, by integrating dark fermentation in existing biogas plants, the overall physical efficiency of the process's substrate turnover can be increased by up to 50% through providing hydrogen in addition to biogas. The achieved test results are examined based on limit‐oriented physical efficiency evaluation to show the potential for optimization of the substrate turnover in biological concepts based on modeling. Finally an overview of a commissioned demonstration plant is given, which will provide further insights into the feasibility of the dark fermentation on an industrial scale.