Well-informed public preferences are key to enabling successful and sustainable energy transitions worldwide. However, limited explorative evidence exists on what the public already knows and wants to know about the electricity generation technologies and their Environmental, Health, and Safety (EHS) risks. Understanding these issues is important for preparing informational materials and facilitating formation of informed preferences. We present results of an explorative interview study with 12 Swiss people. Despite the public debate on energy in Switzerland, we still identify significant awareness and knowledge gaps as well as misconceptions related to both technologies and their EHS risks. For accidental risks, the people tend to think beyond probabilities and consequences and consider further aspects, such as risk controllability and trust in experts and authorities. Most importantly, we find that people are able and tend to think of the electricity system as a whole portfolio: they actively realize the need to deploy multiple electricity technologies and accept some of the EHS risks. We conclude with concrete recommendations for preparing informational materials on electricity sector transitions in Switzerland and elsewhere. We also argue that future social research on energy should pay more attention to public perception of whole technology portfolios rather than single technologies.