A multi-criteria analysis framework for hydrogen carrier evaluation in large-scale intercontinental hydrogen exports

The transition to sustainable energy systems has underscored green hydrogen as a pivotal solution for reducing dependency on fossil fuels. Green hydrogen carriers possess substantial potential for storing and transporting hydrogen globally. To assist in the decision-making process for evaluating and selecting suitable green hydrogen carriers for international hydrogen trade, this study proposes a structured multi-criteria evaluation framework that combines the Analytic Hierarchy Process with TOPSIS and VIKOR to assess five green hydrogen carriers: liquid hydrogen, ammonia, methanol, dibenzyltoluene, and toluene. Performance criteria include techno-economics (levelised cost of hydrogen, internal rate of return), environmental impacts (IPCC GWP100, ReCiPe end-point) and carrier efficiency. The framework is applied to a prospective South Africa to United Kingdom green hydrogen supply chain, with seven sensitivity cases that vary in capacity factors for electrolysers, utility prices, and grid carbon intensity. The case study shows that carriers have distinct performance across criteria. TOL has the lowest levelised cost of hydrogen ($7.07 kg−1H2), whereas liquid hydrogen has the lowest environmental impacts (7.62 kg CO2-eq kg−1H2, 0.77 Pt kg−1 H2) and the best carrier efficiency (77.62 %). The AHP-TOPSIS method selects liquid hydrogen as the near-ideal carrier. The AHP-VIKOR selects methanol in most sensitivity cases and shifts to ammonia when renewable sources supply process energy. The proposed framework provides policy-makers with a transparent tool for evaluating green-hydrogen carriers in international trade and for crafting aligned infrastructure and incentive policies.