Resilience in a critical infrastructure system can be viewed as a quality that reduces vulnerability, minimizes the consequences of threats, accelerates response and recovery, and facilitates adaptation to a disruptive event. In this context, comprehensive knowledge of the environment and of the main factors whereby resilience is determined, limited, and affected can be said to represent the fundamental precondition for strengthening the resilience of critical infrastructure elements. Based on this idea, the article defines the initial and functional conditions for building and strengthening the resilience of critical infrastructure elements, i.e., the resilience concept in a critical infrastructure system. Subsequently, factors determining the resilience of these elements are identified, both in terms of technical resilience (i.e., robustness and recoverability) and organizational resilience (i.e., adaptability). In the final part of the article, these factors are presented in greater detail in the context of case studies focused on the electricity, gas, information and communications technology, and road transport sectors. Determination of these factors is examined with regard to the intensity of a disruptive event and the performance of the respective critical infrastructure element.

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 the last ten years, considerable attention has been paid to analysing and assessing the criticality of railway infrastructure elements. Publications on the subject mostly assess elements only from a certain point of view, such as purpose, reliability or risk. This leads to only a partial assessment of criticality without continuous correlation, which may result some critical elements of the system being omitted. The article introduces the railway infrastructure criticality assessment tool (RICA tool), which was created to evaluate the criticality of railway infrastructure elements in all aspects. The integral approach of the tool lies in comprehensively assessing the technical and process factors of rail transport. The criticality of railway infrastructure elements is therefore assessed not only in terms of the relevance and resilience of elements but also their interdependence, substitutability, risk and impact.

Ensuring territorial safety is one of the state’s main tasks, and the public administration plays a primary role in fulfilling it. The safety and sustainability of a territory is ensured by, inter alia, safety planning, including spatial planning. Spatial planning contains safety requirements for population protection. The requirements for ensuring the safety of the population included in the spatial plan vary significantly between countries. The existing population protection requirements contained in the spatial plan have been unsatisfactory for a long time. The main issue is that they are out of date and difficult to apply. The article presents a new proposed method for determining requirements for the protection of the population, which is based on evaluating the risks in the cities and territory. The specific population protection requirements are determined based on the resulting risks and their scaling. The requirements are classified as general when the territory is not faced with external risks or specific when there are such risks. The method is applied to the conditions of the Czech Republic. In terms of national standard specifics, there are requirements in areas of public infrastructure, public utility buildings, and public benefit measures. The method for determining population protection requirements can be considered applicable in a general form by various countries if the national standards specifics or other aspects are taken into account.

Energy supply is currently considered a key area that is essential for the functioning of the entire society, remaining one of the most fundamental sectors of critical infrastructure worldwide. However, the functionality of energy systems is threatened by a number of threats from various areas, such as natural influences, technological threats, terrorism, and even state-supported organized attacks. For this reason, there is an active effort by all interested parties to achieve a sufficient resilience and sustainability level of these systems. Currently, various tools are used for this purpose, the essence of which is to ensure the preparedness of energy systems. Primarily, basic dependable systems aspects are applied according to the planning documentation and according to the N-1 principle from the transmission system code. These tools are functional and very proven in practice. However, the sprawling threat landscape and the COVID-19 pandemic have shown that the use of individual, separate tools may not comprehensively cover the entire area of preparedness, especially for unexpected events or expected events of unexpected dimensions. To address this challenge, the article takes up the professional abstract recommendation of ensuring the preparedness of the entire system comprehensively, i.e., by involving all possible tools, knowledge, and resources that the critical entity has. It proposes and tailors a Business Continuity Management System (BCMS) for the energy domain. The approach covers the entire management system of the organization, in which it establishes, implements, operates, monitors, reviews, maintains, and improves the continuity of activities in terms of key energy system functions. The aim is to ensure the sustainability of the functionality of the given systems within acceptable ranges. The article presents the targeted BCMS targets, building blocks, and representative implementation methods and tools. It is argued that the proposal is ready for application in the specific area of energy critical entities and systems by providing examples of partial implementation.