Battery energy storage systems for renewable energy integration: A comparative review of battery classification, safety, and sustainability

The transition toward renewable energy systems needs reliable and efficient energy storage to address the discontinuous energy production of solar and wind power. Battery energy storage systems have become one of the most important solutions for improving grid stability, increasing renewable energy utilization, and supporting ancillary services. This paper presents a comprehensive review of the battery chemistry classification used in battery energy storage systems, including lithium-ion, sodium-based, flow, and lead-acid batteries. Their technical characteristics, application suitability, safety concerns, techno-economic performance, and sustainability aspects are compared and discussed. The results show that Li-ion batteries currently dominate the market because of their interesting features like high energy density, low self-discharge, high efficiency, and operational flexibility. Moreover, sodium-ion and flow batteries offer strong potential for future large-scale and long-duration storage applications. Lead-acid batteries remain relevant for low-cost and backup systems despite their limitations. Finally, this review highlights that no single battery chemistry is ideal for all applications, and the most suitable option depends on the specific technical, economic, safety, and environmental requirements of the intended battery energy storage system applications.