A Review on Battery Energy Storage State of Charge Estimation for Grid Integration with Embedded Renewable Energy Generation

The anticipated growth of inverter-based variable renewable energy systems (VRESs) such as solar and wind to the power grid results in an equivalent reduction of conventional synchronous generators, thus reducing the rotational inertia of the power system stability. Battery energy storage systems (BESS) are vital for the future growth of renewable energy systems because they provide varied grid support services including grid stability. Hence, managing the battery state of charge (SoC), is a very important aspect of maintaining its life and managing the variability of renewable energy sources (RESs). Therefore, this paper provides a review of SoC estimation methods including model-based and data-driven approaches. This area of research remains a research gap that requires continuous reporting to reflect the battery SoC true estimation. In addition, this review will help researchers, academics, engineers, and industry choose the most suitable SoC estimation approach for future applications with VRESs.