The containerized battery energy storage PCS solution includes the power conversion system, step-up transformer and protection control system, grid connected switchgear and other equipment, with a variety of automatic control operation modes such as frequency modulation . . The containerized battery energy storage PCS solution includes the power conversion system, step-up transformer and protection control system, grid connected switchgear and other equipment, with a variety of automatic control operation modes such as frequency modulation . . This paper highlights lessons from Mongolia (the battery capacity of 80MW/200MWh) on how to design a grid-connected battery energy storage system (BESS) to help accommodate variable renewable energy outputs. It suggests how developing countries can address technical design challenges, such as. . o Mongolia has significant wind and solar energy resources, yet as of 2023, renewable electricity production was about 9% of the total (6. 5% hydro), well below estimated global average of 30% in 2023, highlighting the need. With a total capacity of 4 GWh, the project is fully equipped with Envision's AI-powered energy storage system. . A Battery Energy Storage System (BESS) significantly enhances power system flexibility, especially in the context of integrating renewable energy to existing power grid. The 160MW/320MWh photovoltaic power storage project in Kubuqi, Inner Mongolia, has recently successfully passed the grid-connected test of the energy storage power station. . Recently, NR successfully won the bid for Mongolia's first photovoltaic (PV) energy storage microgrid project, providing containerized energy storage PCS solution to help Mongolia expand the application of renewable energy.