Carbon Dioxide Capture and Storage (CCS) is assumed to be one of the key technologies in the mitigation of climate change. Public acceptance may have a strong impact on the progress of this technology. Benefit perception and risk perception are known to be important determinants of public acceptance of CCS. In this study, the prevalence and effect of cognitive concepts underlying laypeople's risk perception and benefit perception of CCS were examined in a representative survey (N=654) in Switzerland. Results confirm findings from previous qualitative studies and show a quantification of a variety of widespread intuitive concepts that laypeople hold about storage mechanisms as well as about leakage and socioeconomic issues, which all appeared to influence risk perception and benefit perception. The perception of an overpressurized reservoir and concerns about diffuse impacts furthermore amplified risk perception. Appropriate images about storage mechanisms and climate change awareness were increasing the perception of benefits. Knowledge about CO2 seemed to lower both perceived benefits and perceived risks. Implications for risk communication and management are discussed.