Energy Management System in Microgrids

Renewable energy sources such as wind and solar are intermittent and non-dispatchable compared to conventional energy sources. This makes it difficult to completely rely on these sources to provide a reliable electrical supply. Therefore, the concept of a microgrid was introduced to integrate these energy sources together and provide more reliable electrical supply. Microgrids consist of distributed energy resources (DERs), energy storage systems (ESSs), and loads that are perceived as a single entity. They are generally integrated into low-voltage distribution networks and offer many advantages to the power system such as higher efficiencies, increased reliability, clean energy, and improved quality of supply. Microgrids can be operated in grid-connected mode or in islanded mode. However, microgrids are expensive to implement. Cost-effective solutions for microgrids can be found by optimally sizing its resources and implementing an efficient energy management system (EMS). This study explores the design of an EMS for a grid-connected microgrid using a heuristic method and linear programming (LP) for the optimization. Simulation results show that for the studied network, LP optimization performs better than the heuristic method in terms of maximizing the use of the energy storage system and providing the least operating cost for the system. However, these results cannot be generalized since heuristic methods are problem-oriented algorithms.