Enhancing power systems operational flexibility with ramp products from flexible resources

Abstract

Flexible Ramp Products (FRPs) can address netload variability and uncertainty caused by increasing renewable energy integration. They secure additional ramping capability to follow netload variations of upcoming dispatch intervals. The challenges in current practice of FRP procurement are - 1) Neglecting start-time uncertainty of netload results in inaccurate ramp requirement estimation 2) Inadequate ramping capacity in real-time market for FRP provision leads to the commitment of out-of-merit units 3) Priority in dispatch of renewable energy sources de-commits Conventional Generation (CG) units, thus reducing available ramping capacity. Hence, scheduling FRPs in day-ahead market from CG units and flexible resources along with an appropriate estimation of FRP requirement is essential to ensure ramping sufficiency. In this context, the paper proposes a modified start-time and end-time netload uncertainty based FRP design and a two-stage scheduling framework to integrate FRPs in day-ahead market. Further, system-wide benefits of integrating flexible resources, FRPs and improved operations are highlighted. The proposed framework is simulated on IEEE RTS-24 and reduced Great Britain test systems and proficiency of the method is compared with existing FRP designs. Numerical results indicate a reduction in operating costs and ramping insufficiency with coordinated operation of flexible resources and FRP deployment.