Reduction in liquid hydrogen by weight due to storage in different sizes of containers for varying period of time

Abstract

To reduce the CO2 emissions, many countries have adopted renewable energy mix in their energy production. However, energy produced from renewable energy sources is intermittent in nature. The surplus energy generated from intermittent renewable energy sources is utilized for electrolysis of water to produce hydrogen. Then hydrogen is stored in the form of liquid or compressed gas for later utilization. H2 can be produced, stored, and utilized to generate electricity and water using fuel cell technology at a later time when demand arises. For this reason, an analysis of storage period in a storage medium is required. In this paper, five commercial electrolyzers are selected for hydrogen production. Amount of hydrogen produced from electrolysis of water, electrolyzer efficiencies, and H2 transmission losses for 500 km are estimated. Liquid hydrogen storage method is explained in this paper. Cost of liquefaction and cost of hydrogen storage at onsite and at hydrogen transport distance of 500 km are calculated. This paper attempts to analyze the loss pattern of stored liquid H2 with varying time in storage tanks of different sizes. By considering per day losses of 0.4%, 0.2%, and 0.06% for 50 m3, 100 m3, and 20,000 m3 storage tanks respectively, amount of residual hydrogen after six months, one year, and two years at onsite and at 500 km H2 transportation distance in 50 m3, 100 m3, and 20,000 m3 storage tanks are also estimated using MATLAB calculations. It can be seen from the results that for 20,000 m3 tank, the percentage of initial amount of H2 remaining after six months, one year, and two years are 99.94%, 80.33%, and 33.44% respectively. The corresponding values for small size containers reduce with reduction in size.