The Reliability of Demand-Side Power Flexibility Provision - An Analytical Framework

The growth in the share of renewable energy in-troduces variability and challenges traditional grid management practices, which rely on centralized generators and system support services. Meanwhile, the rise of digitalization across the energy sector offers tools such as demand-side flexibility to manage variability and cope with uncertainty. The reliability of flexibility solutions provided in a bottom-up fashion by distributed energy devices is crucial for their effective integration into system operation practice, requiring risk awareness and systematic assessment. Despite the abundance of experimental research, the reliability aspect of demand-side power flexibility provision has not received adequate attention, which is the gap this paper aims to address. This work presents an analytical framework to assess the reliability of bottom-up demand-side flexibility provision by performing fault tree analysis and failure mode and effect analysis. The results demonstrate that this reliability significantly decreases as the number of components in the flexibility scheme increases. Moreover, the reliability drops to zero within two to five years, depending on the configuration chosen, despite the system maintaining a high steady-state avail-ability between 95 % and 99 %. These results provide bottom- up insights into the reliability and availability of demand-side flexibility intended to support critical infrastructure over a long-term horizon.