Improving Sustainability of Hybrid Energy Systems Part II: Managing Multiple Objectives With a Multiagent System

Hybrid power systems and microgrids may employ a mixture of dispatchable (conventional) and nondispatchable (renewable) generators alongside storage. Whether in grid-connected or grid-isolated (islanded) modes of operation, these systems may face multiple competing objectives when managing diverse installed assets. Power management of hybrid energy systems, therefore, involves operational tradeoffs amongst Pareto-optimal solutions. These attributes, including the ready implementation of distributed renewable generation and the incorporation of methods to locally manage power-networked assets, make them a unique area of study for pursing better sustainable performance. In part I of this paper, storage system round-trip efficiency and operational cost concepts were formulated for use in real-time dispatch decisions towards yielding improved performance of overall system objectives. In this paper (part II), the concepts of part I are implemented with a decentralized multiagent system (MAS). This MAS is employed for power management of a hybrid (diesel-storage battery) microgrid in grid-connected and islanded modes. This paper highlights the development and implementation of an MAS suitable for hybrid and microgrid system applications, as well as presenting an important discussion about the tradeoffs associated with multiobjective design for power management. The simulation results presented demonstrate improvement in sustainable performance of the hybrid system.