Economic Modelling of Energy Security of Distributed Power Systems in the Post-Crisis Period: Scenario Analysis and Assessment of Tail Risks

The paper studies the transformation of energy security of distributed energy systems in the context of growing uncertainty, geopolitical shocks and volatility of fuel markets in order to form theoretical and methodological foundations for increasing the resilience, adaptability and economic efficiency of energy systems in crisis conditions. In contrast to traditional approaches focused mainly on cost minimization, a multi-criteria risk-based optimization model is proposed, combining indicators of economic efficiency (LCOE, CAPEX, OPEX), reliability of the energy system and systemic risk, which is quantified using the notional cost at risk (CVaR). The empirical base of the study is based on the analysis of long-term data of the European electricity market for 2010–2025, supplemented by scenario modelling using simulation and stochastic modelling methods to reproduce exogenous shocks. The results of the analysis confirmed the presence of a structural fracture after 2021, characterized by a transition from a stable mode of operation to a highly volatile state with increased sensitivity of the system to fuel factors. It has been established that the elasticity of the transmission of fuel shocks to electricity prices increases significantly in crisis periods (from 0.21 in 2010–2016 to 0.62 in 2021–2025), which indicates the formation of a fuel-sensitive mode of functioning of energy markets. While increasing the share of renewable energy sources increases the economic efficiency and environmental sustainability of the energy system, it does not guarantee its stability without the introduction of system flexibility tools, such as energy storage and demand management mechanisms. The results of scenario modelling and risk assessment showed that the use of these tools can reduce the level of systemic risk (CVaR) by up to 35% in crisis conditions. In addition, the effect of risk inertia (risk hysteresis) was revealed, which is manifested in the maintenance of an increased level of risk (CVaR = 0.18 in 2024–2025 compared to 0.05 in 2010–2015) even after partial stabilization of the market. This indicates the long-term nature of the impact of crisis shocks on the functioning of energy systems. The obtained results expand scientific approaches to the interpretation of energy security as a dynamic multidimensional category and substantiate the need to transition to risk-based models of energy system management.