## 2 Battery and Hydrogen Energy Storage System
### BESS, HESS, and Other Energy Storage Systems
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**No**} & **Case** & **Details** & **Author/ Year** \\  & **Study/Implementation** & The important goals of lowering greenhouse gas emissions and improving electric energy security are covered in this study. This study looks at the difficulties of incorporating renewable energy sources (RESs) that fluctuate, such as wind and photovoltaic (PV), into current power systems. This is a growing trend over the last ten years. These difficulties include preserving the grid’s ability to operate consistently and dependably in the face of problems with power quality, reactive power support, voltage stability, angular stability, generation uncertainty, and fault ride-through capability. Grid management is made more difficult by the fluctuation in power generation from renewable energy sources (RESs) caused by erratic weather, such as shifting wind and sunshine patterns. Energy storage systems (ESSs) are crucial to reducing these difficulties. When there is a surge in power generation, ESSs store extra energy and release it when needed to stabilize grid operations. This paper provides a comprehensive overview of energy storage systems, emphasizing their main grid integration applications, the various types of storage technologies available (electrochemical, mechanical, electrical, and hybrid systems), and the power converters required to run these technologies effectively. By addressing these issues, the article hopes to help researchers and power utilities choose the most practical and cost-effective energy storage options to improve grid stability and successfully incorporate renewable energy sources. \\ \hline \multirow{7}{*}{**7**} & & This study looks into the viability and economics of deploying hydrogen-based microgrids using photovoltaic (PV) plants with low energy demand, especially on weekends, in places like public buildings and small- to medium-sized businesses. A model for a hydrogen-based microgrid was created by taking inspiration from Sardega Ricerche's Renewable Energy Facility in Italy, which combines a number of energy generation and storage technologies, including hydrogen storage. The model evaluates the microgrid’s expected performance under various load patterns and equipment sizes. An initial economic analysis was carried out to assess the microgrid’s cost-effectiveness. According to the results, the best design approach is to size the PV system 20% larger than the yearly energy consumption and the hydrogen generator 60% larger than the PV system’s nominal power capacity. This arrangement reaches a rate of about 80% self-sufficiency. Furthermore, the levelized cost of energy can be competitive with current Italian electricity prices without the need for public subsidies. This can be achieved together with a significant decrease in initial plant costs, which can range from 25% to 40%, contingent on the load profile. \\ \hline \hline \end{tabular}
\end{table} 
Table 8: _Cont._disposal. Optimization of BESS sizing, scheduling, and degradation management is critical for system efficiency and cost-effectiveness. Safety issues, including fire hazards due to heat production, necessitate the development of thermal management systems and adherence to safety standards. Despite these challenges, BESSs remain a promising technology for grid stability, renewable energy integration, and sustainable power solutions. Ongoing research and technological advancements aim to address these issues and promote widespread BESS adoption [99; 100; 101; 102]. Hybrid energy storage systems (HESSs) offer unique advantages for long-term energy storage and have potential applications beyond electricity generation, including in transportation and industrial processes [103]. These systems combine multiple storage technologies, typically pairing high energy density storage with high power storage capabilities.