Optimal design and energy management of a hybrid PV-Wind system with hydrogen and gravity energy storage: An off-grid sustainable alternative for coal power in Morocco
Mohammed Sahab, Anisa Emrani, M. J. Sanjari, Abdelmajid Jamil, Asmae Berrada
Abstract
Energy storage integration is vital for reliable power supply as reliance on renewables grows. This study investigates the co-optimization and control of an off-grid hybrid system—comprising photovoltaics (PV), wind turbines (WT), hydrogen storage, and gravity energy storage (GES)—as a sustainable alternative to a 624 MW ultra-supercritical coal unit in Morocco. Unlike prior work, this paper explicitly quantifies the distinct roles of GES and hydrogen in coal plant replacement scenarios. A unified framework is proposed to size all system components while performing 8760-hour dispatch simulations to ensure uninterrupted power supply, achieving a 0% loss of power supply probability (LPSP). At this reliability level, the optimal configuration includes ∼1000 PV modules, 594 wind turbines, a GES unit (5 m diameter, 714 m height), and substantial hydrogen infrastructure: a 790 MW electrolyzer, 650 MW fuel cell (FC), and 260 t storage tank. The resulting levelized cost of electricity (LCOE) is 0.23 €/kWh. The system reliably meets demand by leveraging PV, WT, FC, and GES. Intermittency in PV and wind is mitigated through the complementary roles of hydrogen and GES. Hydrogen production aligns with renewable generation, while GES exhibits frequent deep-cycling, highlighting its key balancing function. This analysis demonstrates that a well-sized and controlled PV–WT–Hydrogen–GES system can serve as a credible, clean alternative to coal-based generation. It underscores the potential of hybrid energy storage systems in enabling sustainable, off-grid power solutions, particularly in regions with abundant renewable energy resources.