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At present, China's coal-based power system lacks flexibility and regulation, and the grid dispatching operation mode is relatively rigid, which has become a constraint on the integration and consumption of a high proportion of renewable energy. From 2016 to 2018, China’s curtailment of wind and photovoltaic power totaled 138.9 billion kilowatt-hours, equivalent to the annual output of 30 million kilowatts of coal power plants, corresponding to about 35 billion yuan in coal-fired costs and 40 million tons of carbon dioxide emissions.
In order to achieve the carbon peak in 2030 and the national commitment of carbon neutrality in 2060, it is necessary to allocate multiple flexible resources of the power system from a higher level of planning and mechanism. In this regard, the international environmental protection organization Greenpeace and the team of Professor Yuan Jiahai from North China Electric Power University jointly released a report on the latest research results on China's low-carbon energy transition, "Research on Multiple Improvement Paths for the Flexibility of China's Power System" (hereinafter referred to as the "Report") .
The "Report" systematically analyzes the technical and economic characteristics of various flexible resources on the power supply side, grid side and user side in China, as well as the current status and development space of technology, market and planning flexibility in China, and comprehensively considers flexibility. Resource cost and time scale, and proposed a roadmap for improving the flexibility of China's power system.
"In fact, in order to fundamentally solve the contradiction between renewable energy and traditional coal power in the power system, we cannot completely hope for the flexibility of the existing coal power unit. For various reasons, the '13th Five-Year Plan' was originally scheduled. So far, only a quarter of the 220 million kilowatt coal-fired power transformation target has been implemented." said Li Danqing, director of the Greenpeace Climate and Energy Project.
Yuan Jiahai also pointed out to the China Science Daily that facing the goal of 50% of non-fossil energy generation in 2030, the flexibility of coal-fired power plants alone cannot meet the flexibility requirements of the power system. The cost of flexible transformation of coal power, the cost of frequent startup and shutdown, and the corresponding environmental impacts will limit the long-term effects of flexible transformation of coal-fired power plants, and even increase the overall power supply cost of the power system, which is not conducive to the low-carbon power system Transformation.
The "Report" took Jilin Province as an example and found that in the high-permeability calculation example, adding multiple flexible resources can reduce 39.9% of the amount of wind curtailment, and the number of start-ups and shutdowns of coal-fired power plants. Costs fell by 27.19% and 25% respectively. The interworking of multiple flexible resources such as gas power, energy storage, demand response and grid mutual aid can quickly change output during load peaks and valleys, provide a powerful supplement to the flexibility of the future power system, and further improve the operating efficiency of the power system. Reducing emissions is worth learning from all provinces.
Yuan Jiahai believes that to break the current rigid electricity market distribution pattern, it is necessary to fully tap the potential of existing flexible resources from the power supply side, the grid side and the user side, and enhance the flexibility of the system. In addition, it is necessary to improve the utilization rate of existing transmission channels, strengthen inter-provincial grid connections, take advantage of the UHV transmission network, reorganize the grid structure, and reduce the need for additional flexibility due to grid congestion.
Yuan Jiahai suggested that in the face of the need to develop renewable energy in the medium and long term, we should integrate various types of flexibility resources "source-grid-load-storage", accurately assess future flexibility requirements, and incorporate the power system flexibility improvement goal into the medium and long-term power plan. , And organically connect with planning in various fields of the national economy to promote the coordinated development of flexible resources of "source-network-load-storage".
The "Report" pointed out that, at present, China's thermal power-based power system has insufficient flexibility and regulation capabilities, while the installed capacity of renewable energy is increasing year by year. There is a serious mismatch between the two. From an economic and technical point of view, the coal-fired power flexibility reform carried out at this stage can significantly improve system flexibility. However, with the rapid increase in the demand for flexible resources in the power system, the cost of flexible transformation of coal power, the cost of frequent startup and shutdown, and the corresponding environmental impact will raise the overall power supply cost of the power system, and is not conducive to the low-carbon power system Transformation.
Therefore, the "Report" recommends that it is not advisable to rely on a substantial increase in the scale of coal power installations to support the development of a high proportion of renewable energy. In the long run, it is necessary to reasonably control the installed capacity of coal power, focus on the development of multiple flexible resources such as gas power, energy storage, and demand response, and promote the coordinated and orderly development of coal power and renewable energy.
