Critical review of energy storage systems: A comparative assessment of mechanisms, advantages, challenges, and integration with renewable energy

The worldwide energy transition driven by fossil fuel resource depletion and increasing environmental concerns require the establishment of strong energy storage systems to mitigate the intermittency issues of renewable energy sources. ESS technologies are crucial in maintaining grid stability supply-demand balance and supporting energy demand. This review offers a quantitative comparison of major ESS technologies mechanical electrical electrochemical thermal and chemical storage systems assessing them for energy density, scalability, efficiency, longevity and integration compatibility with renewable energy systems. Among the technologies assessed, hydrogen storage achieved the highest overall score of 24.0, followed by lithium-ion batteries and fuel cells, each scoring 23.0, highlighting their strong potential for renewable energy integration, providing a structured evaluation that enables easy comparison among storage technologies and also aiding in the identification of the most sustainable and practically viable solutions. The review further explores the working principles, advantages, and limitations of each ESS type, supported by recent innovations and emerging trends. Key challenges such as high costs, efficiency limitations, and infrastructure requirements are also addressed with potential mitigation strategies. By consolidating current research and providing a comprehensive, comparative analysis, this paper underscores the pivotal role of ESS in enhancing grid stability, enabling large-scale renewable energy adoption, and achieving long-term sustainability goals.