Integration of Critical Infrastructure and Societal Consequence Models: Impact on Swedish Power System Mitigation Decisions.

Critical infrastructures provide society with services essential to its functioning, and extensive disruptions give rise to large societal consequences. Risk and vulnerability analyses of critical infrastructures generally focus narrowly on the infrastructure of interest and describe the consequences as nonsupplied commodities or the cost of unsupplied commodities; they rarely holistically consider the larger impact with respect to higher-order consequences for the society. From a societal perspective, this narrow focus may lead to severe underestimation of the negative effects of infrastructure disruptions. To explore this theory, an integrated modeling approach, combining models of critical infrastructures and economic input-output models, is proposed and applied in a case study. In the case study, a representative model of the Swedish power transmission system and a regionalized economic input-output model are utilized. This enables exploration of how a narrow infrastructure or a more holistic societal consequence perspective affects vulnerability-related mitigation decisions regarding critical infrastructures. Two decision contexts related to prioritization of different vulnerability-reducing measures are considered-identifying critical components and adding system components to increase robustness. It is concluded that higher-order societal consequences due to power supply disruptions can be up to twice as large as first-order consequences, which in turn has a significant effect on the identification of which critical components are to be protected or strengthened and a smaller effect on the ranking of improvement measures in terms of adding system components to increase system redundancy.