Although huge public acceptance can be observed for renewable energy technologies but when it comes to implementation, public concern has been increasing. The same case can be experienced in recent hydropower expansion efforts in Switzerland as well. To investigate the reasons behind the resistance we conducted a nationwide representative survey with a choice experiment on hydropower acceptance. Results show that having small ecological impacts on aquatic ecosystem would be a prerequisite for any further expansion. The conflicting policy goals, namely increasing hydropower production and preserving rivers, seem to reflect back in public perceptions.