Optimising multi-leg renewable hydrogen networks under deterministic and stochastic demand: Scale economies and operational dynamics with BOG

Green hydrogen produced from renewable electricity can bridge the geographic mismatch of clean energy supply and demand, hence, net-zero through clean hydrogen shipping and transport. This work develops a mixed integer linear programming (MILP) framework to assess the economic viability of a centralised hub using a ‘hub and spoke’ (H&S) logistics model for green liquid hydrogen (LH2) transport, benchmarked against direct-route shipping across four ship capacities: 70,000 m3, 140,000 m3, 280,000 m3, and 420,000 m3 for joint deterministic and stochastic demands incorporating boil-off gas and operational dynamics. A real-world case involving Australia (producer), Singapore (hub), and Malaysia and Indonesia (importers) is used to quantify economies of scale, fleet utilisation, demand responsiveness, and policy implications. Results indicate that the H&S configuration delivers substantial cost advantages relative to direct shipping. The highest savings (∼37%) occur at Ds0.0625-Dm0.1 and saturate to ∼33% for deterministic demands and (∼40-45%) for stochastic demands at mid-range demand levels. Elasticity and gradient-based sensitivity analysis show that total savings are weakly elastic to Singapore demand (≈−0.94), declines with Malaysia demand (≈−0.47), and increase with Indonesian demand (<1), confirming asymmetric marginal responses across regions. These quantified findings provide a decision-support tool for policymakers, implying that net-zero hydrogen policy should prioritise coordinated mid-scale demand aggregation for H&S maximum savings and phased infrastructure deployment, before scaling to the full-demand scenario.