They developed a numerical study to evaluate the influence of groundwater exchanges of UPSH plants using abandoned mines as lower reservoirs. The hydraulic conductivity and the elevation of the piezometric head were analyzed. They concluded that water quality can deteriorate under the influence of UPSH systems when abandoned coal mines are used as lower water reservoirs. [PERSON] et al. [4] carried out research considering large-scale wind and photovoltaic power plants and the potential contribution of PSH plants in the Greek power system. They concluded that the increase of PSH systems is required to integrate large-scale wind and photovoltaic power plants in non-interconnected grids. Compressed air energy storage (CAES) systems consist of one underground reservoir where the compressed air is stored at high pressures. The pressurized air is released and expanded in the turbines in on-peak periods to produce electricity. Currently, there are two commercial diabatic compressed air energy storage (D-CAES) plants using abandoned salt caverns as subsurface reservoirs. The round trip efficiency of D-CAES systems is lower than PSH, reaching typical values of 0.4-0.5. Unlike D-CAES systems, adiabatic compressed air energy storage (A-CAES) systems include a thermal energy storage system, and therefore, fossil fuels are not required to heat the compressed air before the expansion in the gas turbines. Some researchers have determined that the global efficiency of A-CAES systems can reach 0.7-0.8. [PERSON] et al. [5] investigated the thermodynamic performance of A-CAES plants in abandoned mines. An underground reservoir in lined mining tunnels at operating pressures from 5 to 8 MPa and two different sealing layers was considered in the simulations. Analytical and CFD numerical models were conducted for 100 charge (consumption) and discharge (generation) processes. They concluded that the air temperature and the heat transfer through the sealing layer depends on the sealing layer's thermal conductivity. [PERSON] et al. [6] developed a study about the exergy storage capacity potential in United Kingdom's massively bedded halites. Massively bedded halite deposits existing in the UK were considered as CAES reservoirs. They concluded that the exergy storage capacity in salt caverns could provide important support to the electricity grid. Hydrogen energy storage is a form of chemical energy storage in which the electrical power of renewable energies is converted into hydrogen. High pressures (35-70 MPa) are required to store hydrogen as a gas. [PERSON] and [PERSON] [7] carried out an experimental study to compare the hydrogen permeability considering different materials, such as concrete, polymer concrete, epoxy resin, salt rock, and mudstone. The results obtained showed that epoxy resin can be a promising sealing liner for hydrogen storage. Hydrogeological concerns are also very important to determine the feasibility of hydrogen energy storage. [PERSON] et al. [8] simulated a sudden hydrogen leak into an aquifer in France. They carried out an injection test of organic and ionic tracers and helium-saturated water to design the future protocol related to hydrogen storage.