Large-scale overseas transportation of hydrogen: Comparative techno-economic and environmental investigation

Abstract

Overseas hydrogen transport via ships is crucial to meet the global energy supply as we shift from the carbon-based fuel era. In this study, the hydrogen supply chain, which includes chemical and physical storage processes as well as sea and land transport and terminals, was economically and environmentally investigated. Five different storage technologies (i.e., liquid hydrogen, ammonia, toluene-methylcyclohexane [TOL-MCH], dibenzyltoluene-perhydro-dibenzyltoluene (H0DBT-H18DBT), and methanol) were applied to a defined intercontinental hydrogen supply chain that carries 300,000 t of hydrogen per year via ships. The five hydrogen storage technologies were evaluated and compared based on their economic and environmental performance. To achieve a higher energy efficiency, the models were upgraded by integrating liquid natural gas (LNG) to achieve hydrogen liquefaction and utilizing the waste heat of solid oxide fuel cells (SOFCs). Additionally, assuming that renewable energy capacity will be dominant in the future, renewable electricity and green hydrogen usage were investigated. The results showed that the TOL-MCH supply chain is the most cost-effective and environmentally friendly technology with 5.8 $/kgH2 levelized cost and 18.5 kgCO2-eq/kgH2 carbon intensity, followed by the ammonia supply chain, due to its suitable operating conditions. In the case of renewable electricity and green hydrogen dominance, the ammonia supply chain generates the lowest carbon emissions (i.e., 2.23 kgCO2-eq/kgH2) with a cost of 4.92 $/kgH2, and the TOL-MCH chain is the most cost-effective technology (i.e., 4.57 $/kgH2). Therefore, a decrease in process energy consumption and the use of renewable energy sources are essential for efficient and sustainable hydrogen seaborne transport.