The shift towards renewable electricity in the UK has provoked significant localized opposition from the communities obliged to host the transmission infrastructure. This chapter explores the Social License to Operate (SLO) associated with nationally significant infrastructure projects, based on the proposed Kintore to Tealing 400 kV overhead line in northeast Scotland, locally dubbed “monster pylons.” While framed as a nationally significant development essential for grid decarbonization, the project has faced widespread opposition from local communities who feel alienated by its planning process, excluded from meaningful consultation, and disproportionately burdened by its impacts. Drawing on 389 survey responses and four in-depth interviews, this chapter develops an empirically grounded model to assess thresholds of perceived social impact and their correlation with SLO decisions. Results show that SLO declines significantly once negative perceptions of impacts, especially visual disruption, land degradation, and procedural injustice, exceed certain thresholds. Echoing emotional geography, the findings remind us of how place attachments also shape the SLO. Mitigation approaches, such as benefit funds below a certain threshold, are insufficient if they do not address deeper emotional and procedural grievances. The chapter concludes by proposing a list of relevant thresholds of perceived impact tipping points for SLO and a checklist for assessing and securing SLO in net-zero energy transition infrastructure projects.