Comparison of Liquid Hydrogen, Methylcyclohexane and Ammonia on Energy Efficiency and Economy

Among several candidates of hydrogen storage, liquid hydrogen, methylcyclohexane (MCH), and ammonia are considered as potential hydrogen carriers, in terms of their characteristics, application feasibility, and economic performance. In addition, as a main motor in the hydrogen introduction, Japan has focused and summarized the storage methods for hydrogen into these three methods. Each of them has advantages and disadvantages compared to each other. This study focuses on the effort to analyze and clarify the potential of these three hydrogen storages, especially in terms of physical characteristics, energy efficiency, and economic cost. Liquid hydrogen faces challenges in huge energy consumption during liquefaction and boil-off during storage. MCH has main obstacles in largely required energy in dehydrogenation. Lastly, ammonia encounters high energy demand in both synthesis and decomposition (if required). In terms of energy efficiency, ammonia is predicted to have the highest total energy efficiency (34–37%), followed by liquid hydrogen (30–33%) and MCH (about 25%). In addition, from cost calculation, ammonia with direct utilization (without decomposition) is considered to have the highest feasibility for being massively adopted, as it shows the lowest cost (20–22 JPY/Nm3-H2 in 2050). However, in case that highly pure hydrogen (such as for fuel cell) is demanded, liquid hydrogen looks to be promising (24–25 JPY/Nm3-H2 in 2050), compared to MCH and ammonia with decomposition and purification.