A Review on the current accommodation status of renewable energy in China and its methods of improvement in the power and thermal systems

Improving the large-scale renewable energy accommodation plays an important role in accelerating energy transformation and optimizing energy consumption structure, which has outstanding economic significance and environmental benefits. China's vast territory and the renewable resources are rich in the northwest, southwest, northeast, north China. This paper reviews the current accommodation status of renewable energy in China and its methods of improvement in power and thermal systems related in recent research. In latest years, the renewable energy curtailment problems have become more and more serious due to that the existing power systems are not able to absorb the renewable energy with intermittence and randomness. Hence, several methods are proposed to improve the flexibility of power systems, which is needed for the renewable energy up to the power grid. Some of researchers proposed methods in the field of power systems, such as electric storage, power-to-X, virtual power plants, power demand side management, etc. Some of others developed methods in the field of thermal systems, which is closely related to the power systems, such as by-pass auxiliary heating, active heat storage, passive storage, ice thermal storage, etc. Different approaches are compared comprehensively and it is found that only seeking methods within power systems is not enough. Thermal systems contain great flexibility which can be utilized in the power systems. Key issues of research lies in developing combined heat and power dispatch with fully consideration of the operation constraints and performance evaluation index for the power and thermal systems.