Optimal offering and operation strategy for hybrid power plants in hour-ahead mFRR energy activation markets with guaranteed service provision

Utility-scale renewable hybrid power plants (HPPs) have emerged as promising electricity generation resources by combining multiple renewable generation technologies and storage. However, due to overplanting and co-location, storage size is usually smaller than that of renewable resources, which imposes challenges for HPP in providing reliable balancing services. This paper presents a novel model for optimizing the offering and operation of HPPs in hour-ahead manual frequency restoration reserve (mFRR) energy activation markets, with a focus on guaranteed service provision. The model takes into account uncertainties from wind power generation as decision-independent uncertainties, and considers the uncertainties related to the activation of mFRR to be influenced by the offering decisions, leading to decision-dependent uncertainties. The proposed model utilizes a robust two-level optimization approach, where the first level focuses on hour-ahead offering and operation, and the second level handles generation re-scheduling. Then, to ensure the computational efficiency with 15 min resolution, a modified column and constraint generation algorithm is proposed to solve the model. A comparative analysis reveals that the HPP with the proposed model can deliver upward and downward mFRR in 94% and 99% of the activated time, respectively. It meets transmission system operators' required 90% reliability.