A critical infrastructure is a complicated system whose failure (in whole or in part) has a significant impact on national interests, including security, the economy and basic human needs. The system consists of relevant sectors, elements and their mutual linkages. In order to study critical infrastructures, it is necessary to apply a systems approach based on cross-sectoral evaluation and research into the linkages between the individual critical infrastructure sectors. Specifically, it is necessary to describe the individual vertical and horizontal levels of each critical infrastructure and the associated linkages. From this point-of-view, a critical infrastructure is embedded within the broader context of emergencies and enterprises, representing a compact and mutually-interconnected system.This paper focuses on quantitatively assessing the impacts of critical infrastructure failures. It presents a theory of synergistic linkages, their levels and the synergistic effects due to the joint action of impacts, which increase the overall impact on the critical infrastructure and on society. The concepts are formalized in the SYNEFIA methodology, which is applied in a case study involving the critical infrastructure of the Czech Republic. In particular, the methodology is applied to determine the synergistic effects of disruptions to multiple sub-sectors of the Czech infrastructure

As the number of threats and the severity of their impact increases, an ever greater emphasis is being placed on the protection of critical infrastructure. Thus, the issue of resilience, or its assessment and strengthening, is increasingly coming to the fore. The resilience assessment of critical infrastructure, especially in the energy sector, has received considerable attention due to the high level of interest in this issue. However, the issue of strengthening resilience poses a significant challenge not only in the energy sector but also in the entire critical infrastructure system. Despite the great importance of this area, there is not a large number of authors moving in this direction and paying attention to resilience-strengthening tools. For this reason, the aim of this article is to provide the reader with a comprehensive methodological overview of resilience strengthening in the critical energy infrastructure sector. This article also provides an overview of internal and external tools suitable for strengthening resilience and presents a possible procedure for their application to energy critical infrastructure elements.

In terms of service provision, the electricity sector is the most important critical infrastructure sector, on the supply of which the vast majority of society and its basic vital functions depend. Extensive disruption of these supplies would have negative effects not only on basic human needs, but also on the economy and security of the state. For this reason, it is necessary to ensure permanent and comprehensive monitoring of the infrastructure elements resilience level, especially against threats with a multispectral impact on several areas of security. For this reason, the authors of the article developed the Converged Resilience Assessment (CRA) method, which enables advanced assessment of the electricity critical infrastructure elements resilience from the converged security point of view. Converged security in this case combines (converges) physical, cyber and operational security into a complementary unit. This reflects the integral determinants of resilience across related areas of security/safety. The CRA method focuses mainly on information and situation management, which integrates and correlates information (signals) from systems and sensors in order to obtain an overview of the situation and the subsequent effective management of its solution. The practical use of the proposed method is demonstrated on a selected element of the Czech Republic transmission system. The CRA method is currently embodied in a functional sample that has been piloted on several TSO elements. Further development of this method is seen mainly in fulfilling the logic of network infrastructure and reflection between elementary and intersectoral links in the context of synergistic and cascading effects in a broader context.

Managerial decision making is an integral process used in public and private organizations. Critical infrastructure entities are a strategically significant group dependent on the quality of decision-making processes. They aim to provide services necessary to ensure state security and to satisfy basic human needs. The quality of decision making is an important factor in the management of these entities. The quality level is determined by many factors, the key of which is risk management. For this reason, it is necessary for the operators to minimize risks affecting the elements of the critical infrastructure through which these services are provided. Risk management is commonly used for this purpose, making it possible to assess and manage these risks. However, there is a specific group of threats that affects the resilience of these elements. The indication of these threats is not possible through common risk management. Therefore, it is necessary to develop specific scenarios of negative impacts and procedures for assessing their impact on the resilience of elements of the critical infrastructure. To this end, this conceptual article introduces an entirely new managerial decision-making process for indicating the resilience of critical infrastructure elements.