Biomass-to-Hydrogen Conversion: Fundamentals, Technologies and Performance Trade-offs

Abstract

: Hydrogen is attracting increasing attention as a low-carbon energy carrier, but its environmental benefits depend strongly on the production pathway. Biomass provides a renewable feedstock for hydrogen production while enabling the utilization of agricultural residues, forestry wastes, algae, and organic wastes. Major biomass-to-hydrogen routes include gasification, pyrolysis–reforming, hydrothermal gasification, dark fermentation, photo-fermentation, photobiological conversion, and microbial electrolysis. These technologies differ substantially in reaction mechanisms, feedstock requirements, hydrogen productivity, energy demand, and technological maturity. This review examines the fundamental mechanisms of biomass-to-hydrogen conversion and summarizes recent advances in major thermochemical, biological, and bioelectrochemical routes. Particular emphasis is placed on the trade-offs among hydrogen yield, productivity, energy efficiency, environmental impact, and economic feasibility. The analysis indicates that technology selection should be tailored to feedstock characteristics, with thermochemical routes generally favored for dry biomass and hydrothermal or biological pathways offering advantages for wet and organic-rich feedstocks. Future development will depend on integrated biomass utilization and carbon management.