Techno-economic and environmental impact assessment of hydrogen production processes using bio-waste as renewable energy resource

There is a wide spectrum of biological wastes, from which H₂ production can generate clean energy while minimizing environmental degradation. This study aims to conduct techno-economic and environmental impact assessment of major hydrogen production processes such as dark, photo and solid-state fermentation, microbial electrolysis cell (MEC), gasification, pyrolysis and plasma. From the technological point of view, the dark fermentation has shown better performance in comparison to the other processes. However, the hybrid dark fermentation with photo-fermentation and MEC has shown higher performances with around 1 L H₂/g organic waste. Regarding the economic aspect, the cheapest H₂ production belongs to gasification and fermentation with approximately 2 US$/g and 2.3 US$/g followed by plasma (2.4 US$/g), pyrolysis (2.6 US$/g), MEC (2.8 US$/g), and photo-fermentation (3.5 US$/g). Regarding the potential environmental impact, the fermentation process showed the lowest greenhouse gas emission with 15 kg CO_2-eq/kg hydrogen followed by gasification, MEC and plasma. Regarding the potential commercial applications, gasification is the most mature with the highest possible technology readiness at level 9.