Achieving net-zero greenhouse gas (GHG) emissions requires the rapid deployment of renewable energy. Yet, renewable energy projects often generate trade-offs or synergies with biodiversity conservation, landscape protection, and local economic interests. While prior research has emphasized objective trade-offs, political debates are often shaped by perceived trade-offs, including second-order perceptions, meaning what stakeholders believe others perceive to be trade-offs and synergies. Despite their importance for political dynamics, these perceptions remain insufficiently analysed. Here, we address this research gap and examine how different forms of participation, local project leadership, and trust influence stakeholder perceptions of trade-offs and synergies in alpine photovoltaic (PV) projects. Drawing on a mixed-methods analysis of two alpine PV projects in Switzerland in Savognin (Sursés) and Sedrun (Tujetsch), we conceptualize trade-offs and synergies and the measurement of second-order beliefs using a scoping review, and track perception shifts using social network analysis based on 11 semi-structured interviews with key stakeholders. As such, we offer a novel conceptual and methodological tool for detecting shifts in support or opposition over time. This can be useful in many other stakeholder analyses and also for practitioners involved in the planning of renewable energy projects. Substantively, we show that informal, timely, and responsive participatory processes, coupled with trusted local project leadership, reduce perceived trade-offs and increase project acceptance. Overall, our analysis provides a set of tools for mapping stakeholder coalition dynamics based on second-order perceptions and provides important insights into how to adequately balance trade-offs and synergies when harmonizing national-level renewable targets with local needs.