Resilience engineering is becoming a new paradigm for complex systems performance and maintenance decision making. The concept of resilience was introduced by Holling (1973) in the field of ecology and has been well-documented in ecological and social literature and in some management cases. The initial definition of resilience is that it determines the persistence of relationships within systems and is a measure of the ability of these systems to absorb change of state variables, driving variables, and parameters and still persist. Other definitions include “the potential of particular configuration of a system to maintain its structure/function in the face of disturbance, the ability of the system to reorganize following disturbance-driven change and measured by size of stability domain,” and “the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity and feedbacks.” More research has been done on the concept of resilience and its applicability to ecological, social, and business systems in comparison to engineered systems.

Resilience engineering represents a major step forward by proposing a completely new vocabulary instead of adding one more concept to an existing lexicon. Although various definitions of resilience exist that are dependent on the subject area, resilience in infrastructure systems and energy systems (including CO2 sequestration) is the ability of the system to recover and adapt to external shocks, including natural, artificial, and technogenic disasters and failure because of poor design.

This can ultimately affect the smooth and efficient operation of systems and may demand a shift of process, strategy, and coordination. Infrastructure systems in most cases are interconnected. Therefore, analyses of the system should consider interdependency properties. Because of both dependencies and interdependencies, there are various types of effects: (1) cascading effect—when disruption in one infrastructure causes disruption in a second; (2) escalating effect—when disruption in one infrastructure exacerbates an independent disruption of a second infrastructure; and (3) common cause effect—when a disruption of two or more infrastructures occurs at the same time. The last is more prevalent during natural disasters. The interactions create a very delicate web between infrastructures as well as feedbacks and complex topologies at different levels. Therefore, it is nearly impossible to analyze the behavior of any infrastructure in isolation of its environment.