Optimization of a grid-tied microgrid configuration using dual storage systems

This paper presents optimization in capacity sizing and operational schedule for a grid-tied microgrid using dual storage systems. Photovoltaic power system is used as a renewable energy source. Pumped-storage hydroelectricity and battery energy storage system are utilized as energy storage systems. The physical models of the photovoltaic system, pumped-storage hydroelectricity, and battery energy storage system are developed. The objective function is formulated to minimize capital and operational costs of grid-tied microgrid system. The constraints for the optimization are formulated based on the system model, operational limitations, and performance requirements. Capacity and operational schedule for the microgrid system is optimized using solar insolation data and load demand data. Performances required for microgrid system are high renewable energy penetration with low curtailed renewable energy. Mixed integer linear programming (MILP) is used to solve the optimization problem. With the proposed method, renewable energy penetration ratio achieves 50%. The curtailed renewable energy ratio of 10.4% is obtained.