The transition to a hydrogen-based energy economy demands thorough evaluation of environmental trade-offs associated with various production pathways. This study presents a comprehensive life cycle assessment (LCA) of biomass-derived hydrogen production methods, including thermochemical, biochemical, and hybrid conversion routes. The analysis considers feedstock cultivation, processing, conversion, and hydrogen purification, assessing key environmental indicators such as global warming potential (GWP), acidification potential, eutrophication, and energy return on investment (EROI). Results show that while biomass gasification offers high hydrogen yields, it presents moderate GWP due to process emissions. In contrast, biological fermentation routes yield lower environmental burdens but at the cost of reduced hydrogen output. Co-product credits and carbon sequestration via biochar can significantly offset emissions. Sensitivity analysis highlights the influence of feedstock type, process efficiency, and regional electricity mix. The findings underscore the need for integrated process design and regionalized sustainability assessments to guide the deployment of truly green hydrogen technologies.