Indicators to compare risk expressions, grouping, and relative ranking of risk for energy systems: Application with some accidental events from fossil fuels

The comparative assessment of risk issues related to different energy systems across their steps in the fuel/life cycle is highly challenging due to the large variety of heterogeneous risk expressions, and is further complicated by the difficulty in grouping different criteria of evaluation for ranking purposes. Based on our previously developed set of 17 Risk Characterization Indicators (RCIs) to measure different risk facets, a PRA-based logic-related grouping and ranking methodology to compare and rank risks from different energy technologies is illustrated and applied. The application takes into account three fossil fuels (coal, natural gas, and oil) using selected illustrative examples in open-source form, chosen from the database ENSAD (Energy-related Severe Accident Database). The events are processed with the RCIs and ranked according the proposed methodology. The RCIs can be used either for (1) analysis of single events, (2) for comparison of events with similar characteristics, (3) for comparison of different energy technologies based on aggregated values, and (4) within Multi-Criteria Decision Analysis (MCDA) to rank events and energy chains. The benefits and limits of the energy risks comparative methodology are discussed, considering its potential to support the management of energy-related risks.