Integration of cascaded coordinated rolling horizon control for output power smoothing in islanded wind-solar microgrid with multiple hydrogen storage tanks

This paper presents a strategy based on the hierarchical rolling horizon control, also called model predictive control (MPC), for efficiently managing a hydrogen-energy storage system (HESS) within an islanded wind- solar microgrid. An electrolyzer uses electricity generated from renewable sources to produce clean hydrogen, which is then re-electrified by a fuel cell as needed to meet the microgrid's loads. The main contribution lies in the incorporation of multiple hydrogen storage tanks in the HESS, distinguishing it from existing literature, which typically focuses on a single tank. The incorporation of multiple tanks in the HESS enables the storage of large volumes of hydrogen for long-term use, allowing the microgrid to operate autonomously without interaction with the utility grid. In order to ensure optimal performance, the selection of the most suitable device for operation at each time-step is crucial. The proposed control strategy takes into account the economic and operational costs, degradation aspects, and physical constraints of the HESS, while simultaneously ensuring the tracking of reference demands and with the highest priority smoothing out the variations of renewable energy sources. Numerical simulations and a lab-scale microgrid setup demonstrate that the controller effectively manages the HESS thus satisfying economic constraints and optimizing device costs, even when deviations occur between the predicted and real-time scenarios. Furthermore, the inclusion of multiple hydrogen tanks allows the microgrid to both mitigate fluctuations in renewable power sources and effectively meet load demand.