A Review of Energy Storage Technologies and Hybrid Configurations for Renewable-Integrated Power Systems

The global transition towards renewable energy has intensified the demand for efficient, reliable, and scalable Energy Storage Systems (ESSs) capable of addressing the intermittency of solar and wind power. This study presents a comprehensive review of major energy storage technologies, including electrochemical (with a focus on lithium-ion, sodium-ion, and redox flow batteries), thermal energy storage (TES), thermochemical energy storage (TCES), flywheel energy storage (FESS), compressed air energy storage (CAES), superconducting magnetic energy storage (SMES), and pumped hydro energy storage (PHES). The review systematically compares these technologies based on key performance metrics energy density (ranging from 0.1 to 500 Wh/kg), power density (0.2–10,000 W/kg), round-trip efficiency (30–95%), and operational lifespans (5–50 years depending on technology). Electrochemical batteries, particularly lithium-ion, exhibit high energy densities (~150–250 Wh/kg) but face sustainability challenges due to resource constraints. TES and TCES technologies demonstrate superior potential for long-duration heat storage with energy densities exceeding 500 MJ/m³, though limited by system complexity. Flywheel systems provide high power density (up to 10,000 W/kg) but lower energy density, making them suitable for short-duration grid stabilization. CAES systems offer large-scale, long-duration storage with energy efficiencies up to 70%, while SMES provides instantaneous power delivery with exceptional efficiency (>95%) for specialized applications. PHES remains the dominant large-scale storage solution globally, accounting for approximately 181 GW of the 272 GW global installed capacity in 2023. The study concludes that no single technology can satisfy all grid-scale storage requirements. Instead, hybridization strategies and targeted deployment based on application-specific requirements are recommended. This review provides critical insights into current technological limitations, recent advancements, and future research pathways necessary to achieve a resilient, low-carbon global energy infrastructure.