Global green hydrogen site suitability and cost competitiveness: an open-source geospatial and uncertainty assessment across 182 countries

Green hydrogen facility siting is commonly guided either by techno-economic cost minimization or by multi-criteria suitability assessment, yet the extent to which these approaches identify the same development priorities remains unclear. A site that can produce low-cost green hydrogen may not necessarily be suitable. Here, we develop an open-source, spatially explicit framework covering 182 countries that applies both approaches independently to a common technically eligible land base. The framework's methodological novelty lies in independently applying cost minimization and multi-criteria suitability assessment to a common eligible land base, enabling a consistent spatial comparison of cost-optimal and highly suitable locations while integrating spatial exclusions, hourly solar and wind generation modelling, plant-gate levelized cost of hydrogen estimation, spatial water-supply pathways, and Monte Carlo uncertainty analysis. Spatial exclusions reduce globally eligible land to 40%. Solar is the least-cost option across 81% of eligible areas, whereas wind-dominated locations achieve a lower median hydrogen cost of $2.8/kg compared with $3.1/kg for solar. However, it was demonstrated that the lowest-cost locations do not consistently coincide with the highest-suitability areas. These findings show that cost competitiveness and development suitability are related but non-equivalent, and that their combined assessment provides a more robust basis for prioritizing large-scale green hydrogen production.