Liquid hydrogen, methylcyclohexane, and ammonia as potential hydrogen storage: Comparison review

Among the several candidates of hydrogen (H-2) storage, liquid H-2, methylcyclohexane (MCH), and ammonia (NH3) are considered as potential hydrogen carriers, especially in Japan, in terms of their characteristics, application feasibility, and economic performance. In addition, as the main mover in the introduction of H-2, Japan has focused on the storage of H-2, which can be categorized into these three methods. Each of them has advantages and disadvantages compared to the other. Liquid H-2 faces challenges in the huge energy consumption that occurs during liquefaction and in the loss of H-2 through boil-off during storage. MCH has its main obstacles in requiring a large amount of energy in dehydrogenation. Finally, NH3 encounters high energy demand in both synthesis and decomposition (if required). In terms of energy efficiency, NH3 is predicted to have the highest total energy efficiency, followed by liquid H-2, and MCH. In addition, from the calculation of cost, NH3 with direct utilization (without decomposition) is considered to have the highest feasibility for massive adoption, as it shows the lowest cost (20-22 JPY.Nm(3)-H-2 in 2050), which is close to the government target of H-2 cost (20 JPY. Nm(3)-H-2 in 2050). However, in the case that highly pure H-2 (such as for fuel cell) is needed, liquid H-2 looks to be promising (24-25 JPY.Nm(3)-H-2 in 2050), compared with MCH and NH3 with decomposition and purification. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.