What is the current status of China's existing coal-fired power units? Can the task of "making all changes" be completed in 2027?

As the total installed capacity and proportion of new energy sources continue to increase, the demand for flexible adjustment capabilities in the power system has become increasingly prominent. Recently, the National Development and Reform Commission and the National Energy Administration issued the "Guiding Opinions on Strengthening the Construction of Power Grid Peak Regulation, Energy Storage and Intelligent Dispatch Capacity"(hereinafter referred to as the "Guiding Opinions"), pointing out that in-depth implementation of flexible transformation of coal-fired power units will be carried out until 2027 The existing coal-fired power units will be "all changes should be made". Coal power flexibility transformation refers to the specific technical transformation of coal-fired power units to improve the load adjustment capabilities of coal-fired power units and ensure the safe and stable operation of the power grid while consuming new energy power. What is the current status of China's existing coal-fired power units? Can the task of "making all changes" be completed in 2027?

The transformation goal may be completed on schedule

The flexible retrofit of coal-fired power units in China has been carried out for many years. According to the goals mentioned in the Circular on carrying out National Transformation and upgrading of Coal-fired Power Units announced by the National Development and Reform Commission and the National Energy Administration in November 2021, the flexible transformation of existing coal-fired power units should be changed to complete 200 million kilowatts during the 14th five-year Plan period. increase system regulation capacity by 30 million-40 million kilowatts and promote clean energy consumption. During the 14th five-year Plan period, the flexible manufacturing scale of coal-fired power units was 150 million kilowatts. Jiang Shihong, vice president of the General Institute of Electric Power Planning and Design, told China Energy Daily that since 2021, coal-fired power units across the country have completed flexible retrofits of more than 300 million kilowatts. From the point of view of the amount of modification, the flexible transformation has achieved the transformation target during the 14th five-year Plan period ahead of schedule and over the limit. According to the estimated peak regulation capacity with an average increase of 10 percentage points, the effect of the transformation in the past three years is equivalent to releasing more than 30 million kilowatts of regulation capacity. This is basically equivalent to the construction of 30 million kilowatts of energy storage facilities in terms of increasing new energy consumption. " "by the end of 2023, China's existing coal-fired power units were about 1.16 billion kilowatts." Jiang Shihong believes that from the perspective of capacity matching, there are basic conditions to complete the task of "should be changed as much as possible" in 2027. "many coal power projects built in the second half of the 13th five-year Plan and since the 14th five-year Plan have taken into account the need for flexible operation, and this part of the unit can be considered that there is no need to implement flexible transformation for the time being. In addition, the conditions for the flexible retrofit of some special fuels, special furnace-type coal-fired power units and a large number of heating units are relatively limited, so it is roughly estimated that the total scale of "should be modified" in active service units is between 500 million and 700 million kilowatts. After deducting the 300 million kilowatts already implemented, 200 million to 400 million kilowatts still need to be retrofitted from 2024 to 2027, with an average annual transformation of 50 million to 100 million kilowatts. This is lower than or close to the rate of transformation in the past three years. "

Subsequent transformation is still a tough battle

It is not difficult to complete the task, but to change more does not mean to change well. The "guidance" points out that in areas where new energy accounts for a relatively high proportion and peak regulation capacity is insufficient, deep peak regulation of coal-fired power units will be explored on the premise of ensuring safety, and the minimum generation output will reach less than 30% of the rated load. According to Huang Zhong, a researcher in the Department of Energy and Power Engineering of Tsinghua University, in the future, the new power system will rely more heavily on the peak regulation, frequency regulation, voltage regulation and reserve functions of coal power, and the healthy development of clean energy cannot be separated from the support of flexible regulation of coal power. Flexibility transformation technology needs to be standardized, standardized and scientific in engineering application. For example, it is necessary to improve the minimum output technical standards of coal-fired power units and scientifically verify the deep peak regulation capacity of coal-fired power units on the premise of considering safety and environmental constraints. In addition, the transformation needs to consider many factors, such as unit safety, unit economy, equipment life, technical reliability, cost, dispatching operation, policy subsidy and so on. At present, there are many technical routes of flexible transformation projects for coal-fired power units, and there are certain differences in application in different regions, different power grids, and different models, and some of them are not cost-effective and applicable. Although there have been demonstration cases of technological transformation in the industry, it is still necessary to further summarize the existing achievements and experience. " Huang Zhong said. Jiang Shihong also said frankly that now the units with superior conditions have usually given priority to the transformation, and the subsequent units are becoming more and more technically difficult, and the cost of the transformation will also rise significantly, and the flexible transformation still faces some challenges. "for example, the remaining design life of a large number of units is less than 15 years, and the economic support of the existing auxiliary service market and price mechanism for the retrofit of this part of the unit is weak; with the continuous increase in the depth and frequency of regulation, the impact of flexible transformation on the operation safety of units is gradually highlighted, and the cost of operation and maintenance is also significantly increased, resulting in a weakening of the enthusiasm of power plants to promote the transformation. The flexible transformation leads to an increase in the operating time of lower load, which increases the coal consumption of unit operation to a certain extent, and has a negative impact on the energy saving assessment and profitability of enterprises. "

Continue to increase investment from multiple parties

According to the data of the National Energy Administration, by the end of December 2023, the total installed capacity of renewable energy power generation in China had reached 1.516 billion kilowatts, accounting for 51.9% of the total installed capacity of power generation in the country, accounting for more than coal power. The proportion of the total installed capacity of renewable energy in the world is close to 40%. The power system environment faced by coal power in China is becoming more and more complex. Huang Zhong suggested that we should continue to increase investment in science and technology and strengthen the construction of the standard system. Although the national key R & D program of the Ministry of Science and Technology has set up flexibility-related scientific research projects in the special project of 'Coal Clean and efficient Utilization Technology', flexibility-related technologies have also been selected in the first major technical equipment in the energy field assessed by the National Energy Administration, but in view of the huge base and technical complexity of coal power, the relevant investment still needs to be strengthened. At the same time, technical standards are the key to maintaining a high degree of unity and coordination in the industry. Many new technologies and products have emerged in the field of coal power flexibility. The standardization and efficient development of flexible transformation can be promoted by improving the technical standard system, which can ensure the safety, environmental protection and economic operation of in-service units. " Jiang Shihong believes that on the one hand, it is necessary to co-ordinate the relationship between tapping the potential of deep peak regulation, safety, and economy; on the other hand, it is necessary to reasonably arrange power grid dispatching and operation management, and strengthen system operation safety and unit life management. "Power grid dispatching should fully consider the impact of dispatching mode on the safety and economy of unit operation, fully co-ordinate the relationship between the overall demand of the power grid and the task allocation of unit regulation in the network, and constantly improve the level of load forecasting. minimize emergency variable load dispatching. In the operation and management of power plant, we should not only constantly explore and optimize the operation mode, reduce thermal stress impact, but also increase the monitoring means of key equipment and components, reasonably increase the frequency of operation and maintenance, find problems in time, and take measures to avoid safety accidents. "

Wen| Reporter Lin Shuijing