Hydrogen-Based Long-Duration Energy Storage: Technologies, System Integration, and Techno-Economic Performance

Abstract

The escalating integration of variable renewable energy sources has underscored the need for scalable, long-duration energy storage (LDES) solutions to ensure power system reliability and resilience. Hydrogen (H₂) based LDES is a rapidly emerging technology that offers substantial advantages in both retaining large volumes of energy for extended periods and facilitating integration across sectors (electricity, heat, transport). This review provides an extensive overview of H₂-based LDES technologies, focusing on the respective production routes, storage and reconversion methods, integration into overall systems, and optimization using digital tools. A systematic analysis of literature published between 2018 and 2026 is conducted to assess techno-economic performance, life-cycle environmental impacts, and reliability metrics, including loss-of-load expectation (LOLE) and effective load-carrying capability (ELCC). The investigation underscores pivotal challenges related to efficiency losses, infrastructure preparedness, and operational complexity, while highlighting the significance of digital twins, artificial intelligence (AI), and market mechanisms in enhancing system performance. Prospective research avenues and policy implications are examined to support the large-scale implementation of H₂-based energy systems in alignment with Sustainable Development Goal 7.