Cushion and working gases mixing during underground gas storage: Role of fractures

Hydrogen production, transportation, utilization, and storage: Recent advances towards sustainable energy

“…These parameters are crucial for accessing the general inventory of operations towards achieving a decarbonized economy by 2050 [412,413]. Particular attention should be given to working gas (in this case hydrogen) and the cushion gas type (such as CH4, CO2, N2, and even H2 in some cases [16,[414][415][416][417]) to alleviate the water inflow issues, pressure maintenance and increase in the volume of the working gas during withdrawal. A simple schematic between these two gases (working and cushion gas) is shown in Fig.…”