Nanowire-based electrodes represent a promising and innovative architecture for alkaline electrolysers, offering significantly enhanced electrochemical active surface area and current density compared to conventional electrodes, positioning them as a competitive solution for sustainable green hydrogen production. Despite their demonstrated potential at laboratory scale, the environmental implications of scaling up their manufacturing process to pilot scale remain largely unexplored, representing a critical knowledge gap for guiding early-stage eco-design decisions. To address this gap, the present study applies an ex-ant Life Cycle Assessment (LCA) following the ISO 14040/14044 framework, combined with a multi-scenario analysis, to quantify and compare the environmental impacts of nanowire electrode production at laboratory, and a theoretically upscaled pilot scale, modelled through systematic scenario assumptions. The functional unit is defined as 1 cm2 of electrode the functional unit. The life cycle inventory was systematically modelled through scenario assumptions reflecting realistic pilot-scale process optimisations, including the simultaneous processing of multiple membranes in sputtering operations, the use of recycled gold targets, and the recovery and reuse of process solvents. Secondary data were retrieved from the Ecoinvent database. The results demonstrate consistent environmental impact reductions across all assessed impact categories relative to the laboratory-scale reference, ranging from 1–50% in the worst-case scenario to 10–95% in the best-case scenario, with the largest improvements observed in minerals and metals resource use and land use. These findings demonstrate, as expected, that scale-up optimisation strategies can substantially reduce the environmental burdens associated with nanowire electrode manufacturing, although the magnitude of reductions and the distribution of hot spots are highly scenario-dependent, underscoring the importance of multi-scenario LCA as a decision-support tool for the sustainable upscaling of emerging electrode technologies.