The Impact of Energy Dispatch Strategy on Design Optimization of Hybrid Renewable Energy Systems

Within the isolated regions without main power grid connection, the required energy is often supplied by diesel generators. Since this method suffers from emissions of greenhouse gases and high operating costs due to fuel consumption, the idea for replacing it with hybrid renewable energy system (HRES) is gaining more and more attention. By appropriately designing the size of HRES components, both the environment and cost can be saved. For this reason, there have been plenty surveys dealing with design optimization of HRES, whereby most of them apply the simple rule-based control. Since the energy dispatch strategy influences the fuel consumption and therefore the operating cost of HRES, different control strategies can lead to substantially different optimization results. In this paper, the impact of energy dispatch strategy on the design optimization result is elucidated. For this purpose, three control strategies (simple rule-based, advanced rule-based, and dynamic programming) are applied to the same design space and the results are validated based on the life cycle cost. The simulation results show that depending on control strategies, the number of feasible designs is different. Especially the simple rule-based control can realize only the minor part of system designs compared to other two strategies. The fuel consumption is the lowest for dynamic programming, followed by advanced rulebased and simple rule-based control. The life cycle cost for studied case can be reduced by 5∼ 10% by applying optimal control in comparison to other control strategies.