title: Resilience in Critical Infrastructures
Creators: name: Egert, Rolf
Publisher: name: UNSPECIFIED
Year: 2021

description: To the present day, the resilient operation of energy grids relies on the continuous supply of electricity provided by conglomerates of power plants, which adjust their production to the demand of the consumers. Transregional and international connections enable these conglomerates to maintain large amounts of reserve capacities for mitigating deviations from the crucial balance between demand and supply. However, for years, energy grids have been undergoing drastic changes as part of the energy transition towards more economic and ecological smart grids. As a result, a growing amount of electricity is produced by increasingly volatile producers that are distributed throughout the energy grid. Furthermore, formerly passive consumers evolve to so-called prosumers capable of producing electricity locally. Whilst these changes support the goals of the energy transition, they also exacerbate the already challenging task of maintaining a continuous balance between the demand and supply of electricity and threaten the resilient operation of energy grids. This thesis makes the following three main contributions to improve the resilient operation of smart energy grids: We propose a semi-formal model for structuring energy distribution grids as holarchies—dynamic hierarchies that facilitate the autonomous operation of sub-parts (holons). The resilient operation of these holons is improved by involving heterogeneous stakeholders into processes for mitigating the impact of hazardous situations on the continuous supply of electricity. Towards this end, our model empowers stakeholders to offer local resources dynamically as so-called flexibilities to support compensating deviations from the balance between demand and supply. We demonstrate our model by integrating it as a discrete-time simulation environment called HOLEG, which was developed as a part of this thesis. To assess the willingness of people to be increasingly involved in processes for mitigating hazardous situations in energy grids, an online survey was conducted. The results show that people are indeed willing to be more involved; however, numerous concerns related to IT-security and privacy remain. The second main contribution addresses the combined technical challenge of organizing holons within holarchies and allocating available flexibilities to mitigate demand and supply deviations. First, we specify the joint challenge (In this work referred to as the Holon Problem) as a multivariate optimization problem and customize three prominent metaheuristic optimization approaches based on particle swarm optimization (PSO), genetic algorithms (GAs), and ant colony optimization (ACO) to find near-optimal solutions to the problem at hand. Towards this end, we propose and formalize a cost function that allows assessing the quality of solutions to the Holon Problem quantitatively, taking into account operational constraints of holonic energy grids as well as numerous ecological, economic, and resilience criteria. The three metaheuristics are evaluated within a simulated large-scale holonic distribution grid using the HOLEG simulation environment. The results show that metaheuristics are well-suited to find near-optimal solutions to the Holon Problem in situations with both, strict and relaxed time constraints. The final contribution deals with social challenges that emerge from operating energy grids as holarchies and involving people into processes for mitigating hazardous situations. First, we emphasize that knowledge about energy grid topics is a crucial component for people to become more aware and take on an increasingly responsible role within holonic energy grids. Second, we provide reasons why laypersons currently lack energy grid knowledge and discuss the potential benefits of increasing their domain knowledge about the resilient operation of energy grids. Third, we stress that knowledge—by itself—is insufficient to motivate people to become increasingly active and highlight strategies to increase their motivation based on monetary and non-monetary incentives. Finally, we propose a serious game prototype as a means to increase the knowledge of people about energy grid topics. The evaluation results show that the serious game prototype is well-suited to educate people about energy grid topics. Moreover, people experience the serious game as significantly more exciting, motivating, and entertaining compared to a text-based learning approach. In conclusion, this dissertation addresses both technical and social challenges that emerge from the transition of energy grids towards smart grids. Our contributions aid the understanding of sociotechnical interdependencies within future energy grids and advance concepts and methods to facilitate their resilient operation.