This paper shows that interventions based on social norms and on increasing the visibility of people's decisions to others (“decision observability”) present promising pathways of generating public support for renewable energy development. In a laboratory experiment (n = 300), we show that social norms and decision observability increase support for renewable energy, even at a financial cost to oneself: When exposed to pro-environmental social norms, participants donated 35% more money to an existing renewable energy initiative than participants in the control condition (Cohen's d = 0.35). Participants whose decisions were observable to others donated 23% more compared to control (d = 0.23). And participants exposed to both treatments (their decisions being observed by others and learning about norms) donated 69% more compared to control (d = 0.67). In addition, our treatments had a positive effect on participants' post-decisional emotions of happiness and pride, which partly alleviates existing concerns about possible adverse side-effect of social influence interventions. Suggestions for policy makers and for future research in this area are presented.