Comparative Risk Assessment for Energy Systems: A Tool for Comprehensive Assessment of Energy Security

Accidents in the energy sector have been identified as one of the dominant contributors to man-made disasters. Additionally, intentional attacks that are the result of a purposed malicious action such as vandalism, sabotage, terrorism, or war have become a major focus in the past few years. Severe accident risks of different energy chains (fossil, hydro, and nuclear) were analyzed based on the highly comprehensive energy-related severe accident database (ENSAD), which has been established at the Paul Scherrer Institut (PSI). Additionally, probabilistic safety assessment (PSA) has been utilized to address the consequences of hypothetical accidents at nuclear power plants. Comparative evaluations were performed for full energy chains because accidents can take place at every stage of an energy chain. Results are provided separately for Organization for Economic Co-operation and Development (OECD) countries and non-OECD countries to account for differences in technological development as well as management, regulatory frameworks, and general safety culture. Aggregated indicators and frequency–consequence (F–N) curves indicate that fatality rates in OECD countries are substantially lower compared to non-OECD countries. Upstream stages of fossil chains and hydropower in non-OECD countries are most accident-prone, whereas energy-related accident risks are lowest for western hydropower and nuclear power plants, although their maximum consequences can be very large. Finally, intentional attacks on oil and gas installations provide a real threat, resulting in potential health and environmental effects, economic loss, social impacts, and reduction of supply. In conclusion, the inclusive protection of critical infrastructures requires a holistic, multilevel approach within the context of Homeland Security. Keywords: accident; intentional attack; security risk; energy sector; comparative risk assessment; ENSAD database; probabilistic safety assessment; aggregated indicator; frequency–consequence curve