Resilience to High Consequence Cascading Failures of Critical Infrastructure Networks

Critical infrastructure networks such as telecommunications, power, water, natural gas, diesel, transportation, and cyber networks are interdependent with one another, forming a vast and dauntingly complex web of institutions and physical systems that must be engineered and secured for reliability. No single utility operator, engineering consultant, emergency management organization, financial institution, or local, regional or other government entity is capable of understanding, monitoring, or managing the whole system. Yet, failures are unavoidable, and when those failures cascade through the network the result may be high-consequence cascading “catastrophes” or Black Swan events. In one recent and tragic example, the February 13–17, 2021 Winter Storm Uri in Texas initiated a failure in the natural gas production system that cascaded first to the natural gas power generation system and then to the wider ERCOT power system, the water distribution system, and the petrochemical industry of Texas. No single system operator was responsible, and yet the consequences – including fatalities, recovery challenges, regulatory attention, and extreme costs – are everyone’s problem. As networked interdependencies grow, the likelihood of cascading failures has increased accordingly, necessitating technical solutions tailored to this problem. This report introduces the basic principles of interdependent critical infrastructure networks and reviews approaches for analyzing and mitigating the vulnerability of the network to make it resilient. Resilience and reliability in critical infrastructures are complementary and orthogonal. In resilient networks, the inevitable failures due to “all hazards” stay small and don’t become catastrophes.