Component Sizing and Energy Management for a Supercapacitor and Hydrogen Storage Based Hybrid Energy Storage System to Improve Power Dispatch Scheduling of a Wind Energy System

Abstract

As renewable energy sources such as wind energy replace traditional power plants, new methods of component sizing and energy management for hybrid storage systems are necessary to achieve the expected dispatched power level that is committed to supply to the grid for a specific time interval. Electrolyzers (ELs), fuel cells (FCs), and hydrogen storage tanks working as hydrogen energy storage (HES) can, not only offer electrification of the power sector but also offer flexible dispatch power level in the wind energy generation system. To gain the benefits of HES, this study proposes a probabilistic approach to adequately size a hybrid energy storage system composed of a proton exchange membrane fuel cell/electrolyzer, and a supercapacitor (SC) bank. Furthermore, a two-layer energy management to improve power dispatch scheduling for the HES is proposed. Using real-world wind data, the proposed size specification method was simulated and compared to other existing methods. The simulation results demonstrate that the SC within the hybrid energy storage system can aid in the processing of high-frequency fluctuations and avoid the substantial cost of round-trip losses associated with HES. Furthermore, the two layers energy management strategy assists in extending HES operating lifetime, reducing operation cost, and maximizing HES unit utilization by avoiding excessive number of switching between FCs and Els and maintaining an equal number of turning ON/OFF of ELs (charging) and FCs (discharging).