Hydrogen for Long-duration Energy Storage in a Fully Renewable Island Power System: A Case Study of Reunion Island

Abstract:
The transition to fully renewable energy systems poses unique challenges for non-interconnected islands due to the intermittency of renewable generation, limited land availability, and lack of grid interconnections, making long-duration energy storage essential. This paper presents a multi-objective optimization approach to assess the techno-economic and environmental viability of hydrogen energy storage (HES) in future fully renewable island power systems. Using Reunion Island as a case study with three five-year weather periods, results indicate HES is critical during extended low-solar events, though infrequently used. The analysis highlights significant impacts of weather-year selection on optimal HES capacity, underscoring the importance of accounting for climatic variability in island energy planning.