Renewable energy quality trilemma and coincident wind and solar droughts

Renewable energy is essential for power system decarbonization, but extended and unexpected periods of extremely low wind and solar resources (i.e., wind and solar droughts) pose a threat to reliability. The challenge is further exacerbated if shortages of the two occur simultaneously or if they affect neighboring grids simultaneously. Here we present a framework to characterize these events and propose three metrics to comprehensively assess renewable energy quality: resource availability, variability, and extremeness. An examination of long-term data across a vast geographical region shows a strong spatial correlation and temporal coincidence of renewable energy droughts. It also finds a lack of sites that excel in all three quality attributes, which presents a trilemma to investors, system planners, and policymakers. These findings underscore the significance of considering factors beyond mere resource availability and contribute to developing informed strategies for the reliable and sustainable deployment of variable energy resources. The introduction of indicators such as availability, variability, and extremeness significantly alter our understanding of renewable energy quality, posing a challenge for investors, system planners, and policymakers, according to results from a statistical framework and time-series data analysis.