Proposals to develop renewable energy technologies may threaten local values, which can generate opposition. Efforts to explain this opposition have focused on perceived negative aesthetic and environmental impact. Less attention has been paid to a fuller suite of the perceived risks and benefits associated with new energy technologies. This paper thus investigates impacts of an offshore wind farm pertaining to individual perceptions and judgments, and why risks to some ecosystem services might be cause for greater public concern than others. We find that this difference can be attributed to the affective and intuitive ways in which people perceive risk. Our mixed-methods design used interviews (n=27) that involved risk-benefit weighting tasks and an animated visualization to help people imagine an offshore wind farm in a familiar place. We found that affectively-loaded impacts (harm to charismatic wildlife and visual intrusion) were assigned greater weight than more easily quantifiable impacts (displacement of fishing, impact to tourism, cost of compliance with regulations). Interviewees identified increased regional energy self-sufficiency as the most valued potential benefit of an offshore wind farm. These results have implications for ecosystem service assessments generally and, more specifically, for our understanding of ‘affective’ dimensions of development proposals.