Optimal storage strategies are highly region-dependent, influenced by local climate patterns and renewable resource variability. However, the MENA region, despite its high seasonal variability due to cooling demand, remains critically understudied in terms of seasonal energy storage requirements. To address this gap, this study presents an hourly-resolution linear programming optimization model for the investment and operational planning (dispatch) of a fully renewable power system that minimizes total system cost. The system incorporates solar and wind generation with a parallel portfolio of storage technologies, including lithium-ion battery (4 hours) and hydrogen-based seasonal storage. The model is applied to a detailed case study of the NEOM future city as of 2045, envisioned as a crucial testbed for realizing Saudi Arabia’s 100% green energy future. Various power and energy capacity cost combinations of hydrogen storage are tested across multiple grid scenarios: (1) wind-to-solar generation ratios, (2) battery costs, and (3) future climate change impacts.
Our results highlight that complementing batteries with hydrogen-based seasonal storage can substantially enhance renewable utilization while reducing overall system costs. Short-duration batteries dominate for intraday balancing, but hydrogen seasonal storage becomes increasingly competitive primarily by mitigating the need for excessive renewable overbuilding and reducing long-term curtailment. This competitive advantage is most pronounced as energy capacity costs decline and under scenarios with high wind penetration or extreme weather variability, which necessitates multi-week energy reserves. These findings emphasize the importance of diversified storage strategies for achieving cost-effective and resilient 100% renewable power systems, providing strategic insights for NEOM’s energy transition and decarbonization pathways of MENA.