Multi-Interval Solar Ramp Product to Enhance Power System Flexibility

Increasing penetration of uncertain and variable renewable generation in power system necessitates enhanced generation flexibility, to mitigate frequent system imbalances. Generation flexibility can be enhanced by market-based flexible ramp products (FRPs). FRPs facilitate generators up and down ramping support to the system. FRPs are available from conventional and wind generators. However, lower time frame of FRP markets and uncertain wind ramp availability weaken conventional and wind ramp products, respectively. This necessitates wider investigation of ramp availability from alternative sources like solar generation. Solar power providers (SPPs) can participate in FRP markets in addition to energy markets due to the coherency of system ramping requirements with solar generation. In this context, this article proposes a novel multi-interval solar flexible ramp product (SFRP) design. The proposed model uses Gumbel copula-based joint probability distribution of load and wind forecasting errors for FRP estimation. Max-stable property of Gumbel copula considers extreme forecasting errors, to avoid imbalances. The proposed SFRP design also considers both start and end time uncertainty of each interval, as compared to existing end time uncertainty-based renewable FRPs. Case studies indicate that the proposed SFRP design is beneficial to system and SPPs to reduce dispatch cost and increase profits, respectively.