A multi-time-scale joint operation method for renewable energy station, battery energy storage and flexible load under dynamic assessment of power schedule

• Dynamic assessment indicators for the renewable energy’s power deviation. • Optimization strategy for integrated generation unit under dynamic assessment. • Economic flows in integrated generation unit. In the new power system dominated by renewable energy, the grid flexibility regulation resources are increasingly scarce. Therefore, stricter assessments of the power schedules of renewable energy stations (RES) are required. This approach encourages RES to autonomously use their own battery energy storage systems (BESS) and local flexible loads (LFL) to correct power schedule deviations, thereby reducing the demand for grid flexibility regulation resources from the source. The power distribution of RES on a daily time scale exhibits high volatility, and the accuracy of RES power forecasting is low, leading to fluctuations in the scarcity of the grid flexibility regulation resources at different times. Therefore, the assessment of RES power schedules by the grid should also be dynamic. Traditional RES operation methods struggle to meet the rapidly changing assessment requirements for power schedule deviations. First, this paper establishes a dynamic assessment model for RES power schedules, where the assessment price varies across different time periods and increases with the magnitude of schedule deviations. Then, a joint operation method for RES, co-located BESS, and LFL under the dynamic assessment model is proposed, specifically including the day-ahead generation schedule declaration method and the intra-day execution method. Finally, the value realization forms of LFL and BESS under the dynamic assessment model are clarified. Based on this, evaluation metrics for the operational efficiency of the joint operation entity are established, focusing on comprehensive net profit and profit distribution ratios. The case study shows that the joint operation method for RES, co-located BESS, and LFL proposed in this paper can effectively reduce the assessment fees that RES is required to pay under the dynamic assessment model, while also increasing the total net profit of the joint operation entity. Additionally, it enables a reasonable distribution of the profits that LFL and RES should receive.