## 2 Solar-Hydrogen Storage System  
### Solar-Hydrogen Technologies and Storage System  
An innovative method of producing and storing sustainable energy is through solar-hydrogen technologies and storage devices. These systems use concentrated solar power or photovoltaic technology to capture the sun's plentiful energy, which is then used to electrolyze hydrogen gas [64; 65; 66]. The intermittency problem with renewable energy sources like solar power can be resolved with the convergence of solar energy and hydrogen generation [67; 68; 69]. These systems improve the stability and dependability of renewable energy systems by converting solar energy into hydrogen, which allows excess energy produced during times of high solar irradiation to be stored for use at a later time when sunlight is scarce [70; 71; 72]. Sunlight is first collected using solar panels or concentrators, which turn solar energy into heat or power. Concentrated solar power systems direct sunlight onto a receiver to produce heat, whereas photovoltaic systems use solar cells to directly convert sunlight into electrical energy [73; 74; 75]. After being directed to an electrolyzer, where water molecules (H\({}_{2}\)O) are electrolyzed to produce hydrogen (H\({}_{2}\)) and oxygen (O\({}_{2}\)), the heat or electricity produced by the sun is used. When water is exposed to an electric current, it splits into its component parts and undergoes this chemical reaction [76; 77; 78]. Photovoltaics (PVs) use semiconductor materials such as silicon to directly turn sunlight into electricity. Concentrated solar power (CSP) and other solar thermal power systems use sunlight to generate heat for the production of electricity using a variety of devices, including steam turbines. Solar thermal technologies are superior in utility-scale installations, providing continuous power generation through thermal energy storage, whereas photovoltaics (PVs) are modular and scalable for a wide range of applications. While both strategies make use of solar radiation, they vary in terms of deployment scale and energy conversion techniques [79; 80; 81]. After it is created, the hydrogen gas is kept for use at a later time in a variety of storage methods, such as chemical storage, solid-state storage, compression, or liquefaction [82; 83; 84]. Hydrogen may be efficiently and safely stored using these techniques until it is required for the production of energy. When there is a need for energy, the hydrogen that has been stored can be utilized directly as fuel for a variety of purposes, such as driving cars or lighting buildings, or it can be transformed back into electricity using fuel cells [85; 86; 87]. Utilizing a sustainable energy source, effectively storing excess solar energy, and producing clean electricity with minimal greenhouse gas emissions are just a few benefits of solar-hydrogen systems. These systems aid in the shift to a sustainable energy future and lessen the effects of climate change by combining solar energy with the production and storage of hydrogen [88; 89; 90]. Nonetheless, issues including the cost and effectiveness of electrolysis, the storage and transportation of hydrogen, and system integration as a whole still need to be resolved. To overcome these obstacles and realize the full potential of solar-hydrogen technologies for widespread deployment and acceptance, research and development efforts must continue [91; 92; 93]. To use hydrogen as a clean and renewable energy carrier, hydrogen storage (Table 1) is essential [94; 95; 96; 97; 98; 99; 100; 101; 102; 103]. There are various forms of hydrogen storage techniques, each with pros and cons of their own. There are trade-offs associated with each method of hydrogen storage, including cost, energy efficiency, safety, storage capacity, and application compatibility. A number of factors, including the desired use case, energy requirements, infrastructure availability, and regulatory considerations, influence the choice of storage technology [104; 105; 106].