Rey, José Ramón CopaMateos-Pedrero, CeciliaLongo, AndreiRijo, BrunaBrito, PauloFerreira, PauloNobre, Catarina2026-05-132026-05-132024-07-181996-1073http://hdl.handle.net/10400.26/63121Hydrogen is undeniably one of the most promising options for producing energy with minimal environmental impact. However, current hydrogen production is still derived from carbonintensive processes relying on fossil fuels. Biomass is a sustainable and versatile resource that can be converted into hydrogen through biological and thermochemical pathways from a large variety of feedstocks and technologies. This work reviews and compares existing biomass-to-hydrogen technologies, focusing on their characteristics, maturity level, benefits, limitations, and techno-economic and lifecycle environmental impacts. Less-developed biological conversion methods are characterized by low efficiencies and hydrogen productivity. More mature thermochemical routes enable higher efficiencies and hydrogen yields. Overall, while thermochemical processes suit centralized largescale hydrogen production, biological pathways offer decentralized options, necessitating continued innovation for integration into future energy strategies. Some of these technologies, such as anaerobic digestion (best-case: 1.28 EUR/kgH2 ) and conventional gasification (best-case: 1.79 EUR/kgH2 ), emerge as promising, sustainable, and affordable alternatives for renewable hydrogen generation, offering production costs comparable to those of natural gas steam reforming (0.92–2.8 EUR/kgH2 ).engrenewable hydrogenbiomassbiochemical methodsthermochemical methodsproduction costsustainabilityresearch article2026-03-12cv-prod-412935310.3390/en17143530