Analyzing the Impacts of Variable Renewable Resources on California Net-Load Ramp Events

This paper characterizes the ramping features of multiple renewable resources, load and net-load in California using 2016 measured data. The goal of this analysis is to understand the interactions between variable renewable resource ramps and net-load ramps, and delineate the positive and negative impacts. The findings indicated that although the frequency and uncertainty in the system level net-load ramp occurrences increased due to variable renewable integration, there was also a decrease in the average ramp up and down magnitudes by about 20% and 30% respectively, along with decreases in their respective standard deviations by 40% and 20%. At the zonal level, the analyses also indicated a 4-5% decrease in the net-load standard deviations due to wind integration alone at various market scheduling periods. The paper finally concludes with future research needs to better integrate variable renewable ramp forecasts into system operations and planning for economic utilization of resources.