Building offshore windfarms creates a tension between global environmental issues (related to climate change) and local environmental issues. Alongside these “green on green” oppositions (Warren and al., 2005), other tensions exist between environmental issues and local and global economic issues. For local projects to be accepted, a territorial social contract that reflects a “place-based general interest” needs to be constructed. Using the cases of the Saint Nazaire and Saint Brieuc windfarm projects in western France, we study this construction, focusing in particular on the conflict and concertative processes. This leads us to identify four recurrent mechanisms that lie behind the acceptance and agreement of projects: the prioritization of actors and issues; the adjustment of projects; a transactions and compensations game between planners and local stakeholders, but also between local stakeholders; and the construction of new organized proximities, vital for facing the economic and environmental uncertainties related to this type of project. This leads us to highlight the weight of uncertainties and the importance of trust, which is built by a game of proximities that is periodically challenged.