Life Cycle Assessments in hydrogen-based energy storage systems

Hydrogen is increasingly recognized as an element in the effort to decarbonize the energy sector. Within the development of large-scale supply chain, the storage phase emerges as a significant challenge. This study reviews Life Cycle Assessment (LCA) literature focused exclusively on hydrogen as an energy vector, aiming to identify areas for improvement, highlight effective solutions, and point out research gaps. The goal is to provide a comprehensive overview of hydrogen storage technologies from an environmental perspective. A systematic search was conducted in the SCOPUS database using a specific set of keywords, resulting in the identification of 30 relevant studies. These works explore hydrogen storage across different scales and applications, which were classified into five categories based on the type of storage application, most of them related to stationary use. The majority of the selected studies focus on storing hydrogen in compressed gas tanks. Notably, 33 % of the analyzed articles assess only greenhouse gas (GHG) emissions, and 10 % evaluate only two environmental impact categories, including GHGs. This reflects a limited understanding of broader environmental impacts, with a predominant focus on CO₂eq emissions. When comparing different case studies, storage methods associated with the lowest emissions include metal hydrides and underground hydrogen storage. Another important observation is the trend of decreasing CO₂eq emissions as the storage system scale increases. Future studies should adopt more comprehensive approaches by analyzing a wider range of hydrogen storage technologies and considering multiple environmental impact categories in LCA. Moreover, it is crucial to integrate environmental, economic, and social dimensions of sustainability, as multidimensional assessments are essential to support well-informed, balanced decisions that align with the sustainable development of hydrogen storage systems.