Comparative Accident Risk Assessment of Energy System Technologies for the Energy Transition in OECD Countries

This study presents a comparative accident risk assessment for different energy technologies, e.g., fossil fuels (incl. CCUS), Hydropower, H2, Nuclear, and new renewables, in the Organization for Economic Co-operation and Development (OECD) countries. The quantitative analysis is based on the historical observations collected in the Paul Scherrer Institute (PSI)'s ENergy-related Severe Accident Database (ENSAD) and updated using different sources, for the period 1970-2020, whereas for Nuclear a simplified level-3 Probabilistic Safety Assessment (PSA) is applied. Furthermore, for each energy technology, risk indicators, e.g., fatality rate and maximum consequences, are estimated to allow for comparison. Generally, fatality rates for Nuclear, Hydrogen, Hydropower and new renewables perform better than the fossil energy chains. In contrast, maximum consequences can be far highest for Nuclear, intermediate for fossil and Hydropower, and lowest for new renewables, which are less prone to severe accidents. Overall, no technology performs best or worst in all respects, thus trade-offs and priorities are needed to balance the conflicting objectives such as energy security, sustainability, and risk aversion to support rationale decision making.

Keywords: Risk assessment, Energy-Related Severe Accident Database (ENSAD), Fossil fuels, Renewable energy systems, OECD.

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