Two-Stage Stochastic Scheduling of Cascaded Hydropower-Wind-Photovoltaic Hybrid Systems Considering Contract Decomposition and Spot Market

With the advancement of China's electricity markets and the continuous development of renewable energy sources (RESs), it is of great importance to investigate the strategic behavior of RESs in electricity markets. In this paper, a two-stage stochastic optimization model is proposed for a hybrid energy system composed of cascade hydropower plants, wind farms, and photovoltaic stations. Firstly, typical scenarios are generated based on Latin hypercube sampling (LHS) and the K-means clustering algorithm to represent uncertainties of wind-photovoltaic power outputs. Then, with an analysis of China's electricity market structure, a two-stage coordinated scheduling model of hydropower-wind-photovoltaic hybrid systems in electricity markets is established with the objective of maximizing total revenues considering bilateral contract decomposition, the day-ahead energy market, and the real-time balance market. In addition, the proposed model is transformed into a mixed-integer linear programming (MILP) problem for computational convenience. As shown in an analysis of case studies, cascade hydropower plants can compensate for the fluctuation in wind and photovoltaic power outputs to reduce financial risks caused by uncertainties of wind and photovoltaic power generation. Simulation results show that compared with uncoordinated operation, the coordinated operation of hydropower-wind-photovoltaic hybrid systems increases total revenue by 1.08% and reduces the imbalance penalty by 29.85%.