Evaluating Potential Benefits of Flexible Solar Power Generation in the Southern Company System

As penetration of variable renewable power increases, the power system needs more flexibility to manage the variability and uncertainty in the operation process. Allowing solar generation to provide this flexibility can bring substantial benefits to the system. This article evaluates the impacts of flexible solar power generation in the Southern Company power system. The production cost model simulation methodology was used for the analysis, with a 5-min dispatch temporal resolution in the real-time. Enabling a subhourly production cost simulation helps to capture more variability in system load and renewable generation. The solar and wind generation forecasting data were simulated with a realistic nature. A total of 15 scenarios were tested with solar capacities of 2, 7, and 20 GW respectively. Simulation results show that the system may see operational challenges to balance the load and meet the reserve requirements with increased solar penetration level and reduced flexibility due to the retirement of coal plants. Enabling solar power generation flexibility will bring significantly benefits to the system, including reduced penalty costs, increased reliability, reduced solar curtailment, and reduced greenhouse gas emissions. The results also show that energy storage can provide some of the same grid services as flexible solar, thereby reducing the value of flexible solar. Nevertheless, combining flexible solar and energy storage resources could bring additional benefits to the system.