Assessment of environmental impact and energy performance of rice husk utilization in various biohydrogen production pathways.

This work aimed to compare the environmental impact and energy performance of rice husk utilization for biohydrogen production via different pathways using parameters and processes applicable in Southeast Asian countries. Six scenarios were developed by combining each selected biohydrogen production process - electrolysis, gasification and dark fermentation, with different energy production technology. The emission values and energy demand varies depending on the scenarios studied, highlighting the effect of different efficiencies of each biohydrogen production technology. The dark fermentation route has the least environmental impact and the highest energy conversion efficiency. Rice husk used in a co-generation plant to supply process energy creates a purely green technology. Biomass energy ratio provides a basis for the performance of each pathway in terms of the conversion efficiency, emissions and energy demand. The sensitivity analysis is used to identify key parameters and processes to improve the dark fermentation technology.