Quantifying the value of probabilistic forecasting for power system operation planning

•Development of high-quality probabilistic solar forecasting for present and future solar PV buildouts in Southern Company system.•A quantitative method is developed to quantify the value of probabilistic solar forecasting for grid operations.•Transformation of probabilistic forecasts to facilitate grid operations by using a probabilistic dynamic reserve requirement approach.•Simulation results from the Southern company system show that using dynamic reserves determined from probabilistic forecasts are beneficial to the system compared to using static reserve requirements.