The rapid transition toward power systems with high shares of renewable energy raises fundamental questions about how system adequacy, reliability, and resource value should be assessed in a decarbonized electricity sector. While renewable sources such as wind and solar photovoltaics provide clear environmental benefits, their variability, weather dependence, and limited controllability challenge conventional approaches to capacity planning and adequacy assessment. These challenges are further intensified by increasing electrification, sector coupling, and the growing presence of distributed and hybrid energy resources.
Classical resource adequacy frameworks were originally developed for power systems dominated by dispatchable thermal generation. Under assumptions of independent forced outages and statistically stationary demand, probabilistic metrics such as Loss of Load Probability (LOLP), Loss of Load Expectation (LOLE), Expected Unserved Energy (EUE), and Effective Load Carrying Capability (ELCC) have long been used to quantify system reliability. However, the increasing penetration of variable renewable energy introduces weather-driven variability, correlated generation patterns, and climate-related non-stationarity, challenging these foundational assumptions.
This systematic review evaluates whether classical probabilistic adequacy metrics remain structurally valid under high renewable penetration and examines how modelling approaches are evolving to represent correlated renewable variability, storage dynamics, and climate uncertainty. Following PRISMA 2020 guidelines, literature searches were conducted in Scopus, Web of Science, IEEE Xplore, and ScienceDirect for peer-reviewed studies published between 2000 and 2025. Preliminary screening identified 300 records, of which 30 full-text articles were selected for detailed analysis.
Early results indicate that while traditional adequacy metrics remain widely used, their implementation increasingly relies on chronological Monte Carlo simulation and weather-correlated modeling. Significant methodological heterogeneity persists, particularly in ELCC calculation, the representation of multi-day renewable droughts, and the definitions of reliability standards. These findings suggest that adequacy metrics remain relevant but require adapted modeling frameworks for renewable-dominant systems.
