Ex-ante life-cycle assessment of biomass-derived hydrogen via fast pyrolysis and sorption enhanced steam reforming: Addressing scale-up uncertainties

Biomass conversion through pyrolysis and sorption enhanced steam reforming (PY-SESR) is a novel alternative for producing hydrogen at bench scale. This study focused on addressing uncertainties linked to its industrial-scale implementation, comparing it to the process without CO 2 capture (PY-SR), and using steam methane reforming (SMR) as benchmark, which is currently the main hydrogen production route. Both PY-SESR and PY-SR scaled-up processes were simulated in Aspen Plus®, based on experimental bench-scale data. Life-cycle assessment based on process simulation-derived inventories showed that the PY-SESR alternative was the only one resulting in renewable hydrogen production according to the European Renewable Energy Directive (RED III) (3 kg CO₂-eq kg −1 H₂ threshold), attaining net negative emissions (−1.12 kg CO₂-eq kg −1 H₂ ). Nevertheless, its higher energy consumption, mainly driven by sorbent calcination and CO 2 pressurization for storage, led to higher environmental burdens with respect to other indicators. Considering fossil resource use, ozone depletion and freshwater eutrophication, PY-SR was found to outperform both PY-SESR and SMR, while SMR performed better in acidification and use of minerals and metals. Monte Carlo simulations and a sensitivity analysis showed that heat demand and electricity consumption highly contributed to PY-SR and PY-SESR variability, as a consequence of the limitations associated to early-stage process scale-up. • Process simulation, LCA and combined uncertainty and sensitivity analysis • Negative carbon footprint in biomass pyrolysis and steam reforming with CO 2 capture • Tradeoffs in other categories as acidification and use of minerals and metals • CO 2 capture required to qualify as renewable green hydrogen • Low carbon footprint despite early-stage uncertainty linked to heat and electricity