System-Level Assessment of LNG Cold Energy Utilization for Functional Expansion of Regasification Terminals

Liquefied natural gas (LNG) regasification releases substantial cryogenic energy, presenting an opportunity to reframe LNG terminals from simple gas suppliers to integrated energy hubs. This study evaluates the system-level integration of two parallel organic Rankine cycles (ORCs) with hydrogen production pathways-proton exchange membrane water electrolysis (PEMWE) and seawater direct electrolysis (SWDE)-to assess their economic and environmental feasibility. A comprehensive techno-economic analysis and life cycle assessment reveal that, owing to the dominant influence of LNG feedstock costs and large LNG throughput, the integration of these systems results in only marginal variations in the minimum selling price and global warming potential of natural gas. Among the evaluated pathways, ORC-PEMWE demonstrates a more favorable balance, enabling low-carbon hydrogen production (0.42 kg CO₂-eq/kg-H₂), whereas SWDE remains constrained under the current assumptions due primarily to the conservative replacement interval and associated replacement costs, together with its higher assumed capital requirement. Furthermore, an environmental techno-economic assessment indicates that capital expenditure-oriented policy support is more effective than carbon credits in improving system competitiveness. Overall, this work provides a realistic, policy-relevant framework for transforming existing LNG infrastructure into multifunctional energy systems while maintaining economic feasibility.