Energy storage system (ESS) is recognized as a fundamental technology for the power system to store electrical energy in several states and convert back the stored energy into electricity when required. Some excellent characteristics such as availability, versatility, flexible performance, fleet response time, modularity etc., make ESS more attractive for power system applications. The ESS has signification contributions and applications to operate the po. Energy storage system (ESS) is recognized as a fundamental technology for the power system to store electrical energy in several states and convert back the stored energy into electricity when required. Some excellent characteristics such as availability, versatility, flexible performance, fleet response time, modularity etc., make ESS more attractive for power system applications. The ESS has signification contributions and applications to operate the power system optimally in power grids with and without integrating renewable energy (RE) systems. This paper presents a comprehensive review of ESS technologies and their applications in power grids. Five different types of ESS, namely mechanical, chemical, electrical, electro-chemical and thermal, are elaborately explored with their key characteristics and applications. A summary of comparative analysis to find the appropriate ESS for power system applications and an analysis of the practical implementation of different ESS worldwide have been presented briefly, reflecting the suitability of ESS for power system applications. The comparative analysis further demonstrates the nature of various ESS, including their advantages and limitations in specific applications. The major challenges from these analyses are identified to be the capacity of ESS, RE integration, high maintenance and implementation cost of ESS, ESS degradation, waste management and associated environmental pollution. Moreover, the review finds out that there are still numerous challeng. ••Various energy storage systems with their key information and a technical comparative analysis are presented.••Applications of various energy storages with their technical advantages and possible challenges are elaborately discussed.••A comparative analysis of different ESS for an appropriate selection for power grid applications is presented.••Few current and past commercial projects of ESS around the globe, and potential directions to promote ESS are discussed.••ESSEnergy Storage SystemRERenewable EnergyEMSEnergy management strategyHESSHybrid Energy Storage SystemMESMechanical Energy StoragePHSEnergy storage systemPower gridMicrogrid systemRenewable energy systemEnergy managementPeak load shavingNowadays, the modern world is becoming more contemporary day by day. Electrical energy is the main driving force in every step of life, consuming almost every sector from residential houses to large industries. The generation of electricity mainly depends on the conventional energy generation system like gas−fired generators, diesel generators, coal-fired generators and so on. Recently, the industries of developed and developing countries are consuming most of the electric energy. Large industries are consuming almost one-third of the total generation and it is increasing day by day. By consuming this large amount of energy, global issues are appearing alarmingly. Due to the generation of non-renewable energy, the climate is changing and if it continues to change, the earth will be in danger.The conventional energy generation system mainly uses natural gas, coal, diesel, and so on, which is primarily responsible for carbon emissions and other greenhouse gasses. The emission of carbon and other greenhouse gasses results in increases in global temperature day by day. Low carbon emission, prevention of the temperature of the earth, lower cost of installation, maintenance cost reduction, power quality improvement and so on can be achieved by using RE generation in the state of conventional energy generation. Solar, wind, hydro, and geo-thermal energy are some examples of RE sou.
