Johanna Voß, Jens Poeppelbuss
Green hydrogen represents a critical pathway for decarbonisation, yet the development of international hydrogen value chains remains constrained by economic uncertainty, regulatory complexity, and the need for cross-sectoral coordination. The development of a functioning hydrogen market therefore requires a better understanding of the international actors involved, the activities they perform, and the relationships shaping market development. Addressing this gap, this study analyses a representative hydrogen value chain using an innovation ecosystem perspective. Drawing on expert interviews, a multi-stakeholder workshop, and validation interviews, we identify 51 actors across 14 stakeholder groups and derive five distinct relationship types shaping hydrogen market development. The results reveal that strong collaboration, shared interests, and symmetrical interdependencies across the core hydrogen supply chain support coordinated market development. Collaborative relationships between the supply chain, political institutions, and supporting actors further facilitate regulatory coordination and knowledge exchange. At the same time, weak collaboration, varying levels of shared interests, and asymmetrical interdependencies involving financial and public actors emerge as major coordination challenges that may hinder market development. By conceptualising relationship types based on collaboration, shared interests, and interdependence, the study contributes to innovation ecosystem research through a more nuanced understanding of relational dynamics within emerging ecosystems. Empirically, it enriches hydrogen research by demonstrating how heterogeneous international actors and their relationships jointly shape market development. The study further provides practical implications for industry and policymakers, highlighting the importance of stronger collaboration with financial and societal actors for accelerating the energy transition.