Abstract
This paper presents an analysis framework for identifying and quantifying variable renewable energy (VRE) drought events using historical operations dispatch wind and solar generation data. We apply a sliding-window methodology across multiple electricity markets (USA, Spain, Portugal, Australia) to measure VRE drought frequency, duration, and energy deficit magnitude. Results show that wind droughts are predominantly short-duration (<24 hours), while solar droughts are more sensitive to threshold definitions and often span 24–48 hours. Moreover, resource and geographic aggregation significantly mitigate VRE drought frequency. This study highlights how VRE drought sensitivity parameters influence their identification and discusses implications for operational planning. We find that most VRE drought events can be managed within the operational planning time frame, wherein long-duration energy storage (LDES) can support system operators in shoring the gap between short-duration system reserves and longer-term planning.