Fueled by sunlight, clouded by concern: Risk perceptions and risk-risk tradeoffs regarding solar fuels from artificial photosynthesis in Germany

Abstract

Mitigating climate change requires societal transformation, including decarbonization innovations, as CO 2 emissions remain the primary driver of global warming. One emerging solution is solar fuels, produced through artificial photosynthesis by integrating green hydrogen, carbon capture and utilization, and engineered microorganisms. While solar fuels offer a pathway for reusing CO 2 and reducing fossil resource dependency, they also generate new risks, uncertainties, and complex risk-risk tradeoffs. Traditional risk assessments rely on expert judgments of probability and impact, overlooking public risk perceptions shaped by personal values and experience. Yet these lay perceptions are critical for public acceptance of sustainable technologies: neglecting them risks public resistance, legitimacy deficits, and implementation failure. This study is the first to systematically map and quantify lay risk perceptions of solar fuels. We used mental model interviews ( N = 24) to map and categorize laypeople's perceived risks associated with (1) the solar fuel production process and (2) the resulting fuel product. Perceived risks were categorized using established typologies of risk types and risk-risk tradeoffs. A confirmatory survey ( N = 292) quantified perceived salience of these risks. Results indicated that production spanned all categories (natural, technological, biological, economic, demographic, political, and medical risks), while product risks excluded natural ones. Production risks mostly entailed risk transfers, while product risks entailed risk offsets. Key concerns included accidents, industrial monopolies, and affordability. Lowest concerns included safety standards and public funding. Our findings highlight the importance of integrating societal risk perceptions into communication and governance, as they represent critical preconditions for societal acceptance.