Energy storage systems are a fundamental part of any efficient energy scheme. Because of this, different storage techniques may be adopted, depending on both the type of source and the characteristics of the source. In this investigation, present contribution highlights current developments on compressed air storage systems (CAES). The investigation explores both the operational mode of the system, and the health & safety issues regard. Energy storage systems are a fundamental part of any efficient energy scheme. Because of this, different storage techniques may be adopted, depending on both the type of source and the characteristics of the source. In this investigation, present contribution highlights current developments on compressed air storage systems (CAES). The investigation explores both the operational mode of the system, and the health & safety issues regarding the storage systems for energy. The investigation also includes a detailed conclusion, which summarises the vast significance of novel energy storage technology. The investigation thoroughly evaluates the various types of compressed air energy storage systems, along with the advantages and disadvantages of each type. Different expanders ideal for various different compressed air energy storage systems are also analysed. Design of salt caverns and other underground and above compressed air storage systems were also discussed in terms of advantages and disadvantages.••••State of the art of Compressed Air Storage Systems.••Criteria of selecting Compressed Air Storage Systems.••Economic impact of Compressed Air Storage Systems.Renewable powerExpandersHealth and safetyFossil fuelThe world is currently exploring new methods for generating energy, instead of relying on fossil fuels. Primarily due to the devastating effects the burning fossil fuels has on the environment, but also considering the fact that fossil fuels are rapidly depleting. Other factors regarding price of fossil fuels being unstable are also key contributing factors that necessitate a need for alternative sources of energy generation. The high demand for energy is directly proportional to worldwide population growth, industrialization as well as technological advancement [,]. A closer look at global energy consumption in 2019 reveals that primary energy consumption increased by 2.9%. This year also witnessed more than a 2% increase in carbon emissions as directly related to electricity generation and the automotive industry. This increase is the highest in the past decade, as the maximum increase in carbon emissions prior was 0.6 CO2Gt. Since most reliable and common way of energy production always involve fossil fuels oil, energy production, especially as electricity, contributes to one third of total fuel needed worldwide (32%). For example, coal accounts for 26% of total world energy supply that will be converted to electricity, whereas gas contributes to 23% to fuel used annually and biomass contributes 10%. Biomass, as well as electricity can be divided into hydroelectricity, nuclear and renewables. Analysis of data compiled from 2000 to 2019, shows an increase in various types of energy generation sources, with the exception of only renewa. Compressed air energy storage (CAES) is the use of compressed air to store energy for use at a later time when required,,,,. Excess energy generated from renewable energy sources when demand is low can be stored with the application of this technology. Compressed air energy storage systems may be efficient in storing unused energy, but large-scale applications have greater heat losses because the compression of air creates heat, meaning expansion is used to ensure the heat is removed [,]. Expansion entails a change in the shape of the material due to a change in temperature. The heat generated during compression can also be stored and used later during the expansion (discharge) stage, which further improves the storage efficiency, as the same amount of heat stored is used later. The compressors- one of the key components of compressed air energy storage systems operate using prime movers, such as motors [,]. These compressors pressurize air as it starts its journey into the storage cavern. The motors required for driving the compressors can also be powered using energy from renewable sources such as photovoltaics or wind turbines [,]. Heat exchangers are coupled to these compressors to extract and store thermal energy,,. This is useful during the discharge phase as air is heated using heat exchangers with the same heat that has been extracted [,]. The expanders, or air turbines are important as they produce work, which is transformed into electricity by co.