The system needs assessment carried out by ENNOH identifies where hydrogen infrastructure may be required in the future to ensure an efficient, reliable and well-connected European hydrogen network. The analysis examines regional and cross-border supply–demand balances, evaluates network adequacy and resilience, considers flexibility needs such as storage and alternative supply routes, and determines where infrastructure reinforcement or expansion might be needed. This assessment provides a methodologically transparent view of Europe’s future hydrogen system requirements. ENNOH does not prioritise projects, does not make investment decisions and does not influence PCI or PMI selection outcomes; its role is to provide an objective analysis of system needs to support evidence-based infrastructure planning.