Capacity optimization of thermal units transmitted with wind power: A case study of Jiuquan wind power base, China

•Introduce the characteristics of Jiuquan wind power base, a typical one in China.•Analyze the feasibility of co-transmitting thermal units with Jiuquan wind power.•Propose a model for optimizing capacity of thermal units combined with wind power.•Several sensitivities which influence the net transmission profit are examined.

According to the national wind power plan in China, seven wind power bases, each with an installed capacity of more than 10,000 MW, will be built by 2020. In this work, based on the output characteristics of Jiuquan wind power base—a typical case among the seven wind power bases, a definition of STC duration curve is presented, and the relative costs and transmission benefits of co-operating thermal units and wind power bases are studied. The capacity optimization model for thermal units combined with a wind power base is proposed, in order to maximize the net transmission profit of transmitting wind power and thermal power. Furthermore, a two-layer optimization method is introduced to solve the model. In Jiuquan wind power base, the net profit from the wind power plant combined with the optimal thermal units is about 51.2% higher than that of wind power plant alone. The influences of the coal price and electricity price on the net profit are analyzed, and the impact of CO2 price on the optimal schemes is also studied.