Integration of large battery storage system into distribution grid with renewable generation

This paper describes the development and implementation of a method and a prototype solving the problem of optimal integration of the largest battery energy storage system installed so far in Switzerland into an existing power grid in presence of intermittent renewable energy sources. The developed approach is based on model-based predictive control, a well-known method in process automation. Mathematical models of all involved system components, such as local load or weather dependent power generation profiles, were developed. In addition, plant-model uncertainties are handled by an additional fast corrective feedback control loop. The result, an advanced battery controller, has been implemented in cooperation with ABB Ltd. in a real-time prototype and integrated into the existing energy management system used for the manual operation and control of the real 1MW Li-Ion battery installed by the electric power utility of the canton of Zurich (EKZ) in Switzerland. The newly developed functions include automatic peak-shaving and cost optimal battery control subject to time-varying energy prices and predefined physical and operating limits.