Hybrid Energy Storage Systems for Microgrid Applications: Integration Architectures, Control Strategies, and Optimization Methods

Abstract

: The increasing penetration of renewable energy sources has made microgrids an important platform for local energy consumption, resilient power supply and flexible grid interaction. However, the variability of photovoltaic and wind generation, together with frequent changes in load demand and operating mode, places higher requirements on energy storage systems. A single storage technology usually cannot simultaneously provide long-duration energy support, fast transient response, long service life and acceptable economic performance. Hybrid energy storage systems (HESS), typically combining energy-type devices such as batteries or flow batteries with power-type devices such as supercapacitors or flywheels, provide a practical route for coordinating different time scales of power regulation. This review summarizes the functional complementarity of major storage technologies, compares common HESS integration architectures, and discusses hierarchical power allocation, source-storage-load scheduling, model predictive control and data-driven optimization methods for microgrid applications. Techno-economic and environmental evaluation indicators are also summarized to support engineering decision-making. Finally, representative application scenarios, current bottlenecks and future research directions are discussed. The review indicates that modular integration, adaptive control, life-cycle cost evaluation and standardized assessment frameworks will be key to the wider deployment of HESS in renewable microgrids.