Articulating conditions for geological carbon storage: Conditional acceptance in three European communities

This study examines how communities in three European contexts (depopulated rural Spain, rural industrial France, and coastal Portugal) articulate conditions for accepting geological CO2 storage. Drawing on engagement activities conducted within a Horizon 2020 project (2021-2026) across regions with no prior carbon capture and storage (CCS) experience, we identify a pattern of conditional acceptance that is not well captured by binary framings of support or opposition. Most participants articulated specific, interconnected requirements spanning four domains: safety (independent verification), benefits (enforceable commitments), transparency (information access), and governance (participatory oversight). While this structure was consistent across contexts, its content was mediated by local factors: territorial justice concerns in depopulated rural Spain, industrial continuity imperatives in the Paris Basin, and competing environmental visions in coastal Portugal. We propose the concept of an implicit psychosocial contract, that is, the set of interconnected conditions that communities treat as prerequisites for entering meaningful dialogue about a potential storage installation, as a framework for understanding these patterns. Informational approaches may be a starting point for broadly supportive communities, though participatory engagement remains important across contexts. Where communities hold mixed views, dialogue-oriented processes that address the terms of conditional acceptance may be essential. These findings suggest that governance design, not only communication strategy, is central to the social feasibility of geological CO2 storage.