"In 2020, the amount of 'abandoned water' in the country's major river basins will be about 30.1 billion kwh, a decrease of 4.6 billion kwh compared with the same period last year. The 'abandoned water' mainly occurs in Sichuan Province. The amount of 'abandoned water' in its major river basins will be about 20.2 billion kwh, mainly concentrated in the main stream of Dadu River, accounting for about 53% of the province's abandoned hydropower." At the online press conference held recently in the first quarter of 2021, the national power administration reported the construction and operation of hydropower in 2020, and Dadu River was named due to the outstanding problem of "water abandonment".





Dadu River is the largest tributary of Minjiang River System in the Yangtze River Basin and one of the three major rivers rich in hydropower resources in Sichuan. Its main stream and main tributaries have 33.68 million kilowatts of hydropower resources, accounting for 23.6% of the total hydropower resources in Sichuan Province; The 28 cascade hydropower stations planned to be resettled have a total installed capacity of about 27 million KW, ranking fifth among China's top 13 hydropower bases. Because the power point is close to the load center of Sichuan, Dadu River was once known as the "first ring road" of Sichuan Hydropower.




However, according to the reporter, this "loop" has been blocked for a long time, and the power of "abandoned water" has exceeded 10 billion kwh year-on-year, becoming the hardest hit area of "abandoned water" in Sichuan and even the whole country. It is worth noting that, in addition to the existing power stations, many new power stations in the Dadu River basin that will be completed during the 14th Five Year Plan period are also facing the risk of "abandoning power when put into operation".







"From 2015 to 2019, the power station subordinate to Guoneng Dadu River alone will generate more than 40 billion kwh of 'waste water'."




Dadu River Basin has a large amount of hydropower resources, superior development conditions and location advantages. It is a rare hydropower treasure house in China. Among the three major rivers of Sichuan Hydropower - Jinsha River, Yalong River and Dadu River, Dadu River enjoys the advantages of short transmission interval, low line investment and low line loss because it is closest to the load center of Sichuan. Under this background, the 12th Five Year Plan for power development issued by the State Council in early 2013 clearly proposed to "comprehensively promote the construction of Dadu River hydropower base", and listed 11 power stations such as Shuangjiangkou and monkey rock as the development focus.




However, due to the difficulty of sending out, the resource advantages of Dadu River have not been fully released. The reporter found that at the press conference held by the national power administration in recent years, the Dadu River was named several times for its outstanding water abandonment problem: in the first three quarters of 2020, "the 'water abandonment' mainly occurred in Sichuan Province, mainly concentrated in the main stream of the Dadu River, accounting for about 57% of the province's' water abandonment 'electricity"; In the first three quarters of 2019, "the 'waste water' mainly occurs in Sichuan Province, and the power of the 'waste water' in the main river basin reaches 21.03 billion kwh, mainly concentrated in the main stream of Dadu River"; In the first three quarters of 2018, "the basin with severe 'water abandonment' is the Dadu River Basin, which is limited by the transmission project"




Many people in the industry also confirmed that the Dadu River has become "the most severe River in the country". A local person familiar with the situation told the reporter: "from 2015 to 2019, only the power station subordinate to Guoneng Dadu River has more than 40 billion kwh of 'waste water'."




What has hit the bottom of the well is that the consumption pressure continues to intensify. According to the above people, the design installed capacity of Shuangjiangkou and Jinchuan power stations under construction is 2 million KW and 860000 kW respectively. Both plans to put the first unit into operation at the end of 2024 and fully put into operation in 2025. Because the transmission line is delayed, the two stations are likely to "abandon water when put into operation". "In addition, Badi, Danba, pusigou and other power stations in the upper reaches of Dadu River are in the early stage of preparation, with a total planned installed capacity of about 5.32 million KW. Sort out the construction scheme of the power stations that have been put into operation, and refer to the construction period of the same type of lines in Sichuan. From the review of the access scheme to the completion and operation, the 500 kV lines will be built for at least 5 years, and the UHV lines are expected to be built for 6-7 years. In addition, they will pass through the Longmenshan earthquake zone, Wolong National Nature Reserve and other places Sensitive areas, construction is even more difficult. It can be said that the "water abandonment" of the power station under construction is a high probability event. "




During the "two sessions" in Sichuan in 2021, Tan Hongen, chairman of State Grid Sichuan electric power company, proposed that during the "14th five year plan" period, many large hydropower stations will be put into operation in the middle reaches of Yalong River, the upper reaches of Dadu River and the upper reaches of Jinsha River, and there is an urgent demand for grid connection and transmission. For example, the ABA high-quality Hydropower Group represented by Shuangjiangkou is now under construction with a capacity of 3.6 million KW; In the middle and late period of the 14th five year plan, the newly installed capacity is planned to exceed 6.5 million KW. "If it is impossible to open up new channels to ensure its delivery and consumption, the opposition between clean power consumption and consumption during the 14th Five Year Plan period will far exceed that of the 13th five year plan."




"Up to now, there is no special channel for Dadu River Hydropower Station", "with the hydropower station under construction put into operation, the problem of lack of channel will be further highlighted"




In view of the large amount of "abandoned water" in 2020, State Grid Sichuan electric power gives the following reasons: first, the installed capacity of hydropower in Dadu River Basin reaches 22.1 million KW, accounting for 52% of the total installed capacity of the provincial direct dispatching plant, which is basically the same as that of "abandoned water"; Second, the hydropower transmission in Dadu River Basin is more constrained by the grid, and the channel is blocked; Third, the water inflow of Dadu River Basin is relatively stable in the wet season over the years, and it is particularly abundant in the wet season in 2020; Fourth, the other two rivers in Sichuan - Yalong River and Jinsha River Basin, the main power stations belong to the national water transfer, and the waste water of the national water transfer power station itself is less.




However, many people in the industry believe that the central reason for the high power consumption of "abandoned water" in Dadu River is the lack of ability of delivery channels and the severe blockage of grid structures.




Unlike other river basins, the power stations put into operation in Dadu River are located in Sichuan Province for consumption. Under the condition of satisfying the demand in Sichuan Province, the surplus power in flood season can be sent out. "According to the original plan, part of the power will be sent to Sichuan through Ya'an Wuhan 1000 kV high voltage communication, but later, due to the cancellation of the project, the original plan has lost its foundation. Up to now, Daduhe hydropower has no special channel and can only use the existing channel to send out." These people said.




However, because the capacity of the delivery channel is far lower than the existing installed capacity, there is a severe lack of channels in the flood season. "The power supply structure dominated by hydropower in Sichuan Province determines that there is a natural mismatch between its power supply and the power load characteristics in the province, and it needs to go through the national market to balance and absorb the electricity in the flood season. However, at present, the overall transportation ability of the trans provincial transmission channel is lack, and it is given priority to the use of the national dispatching units, and the surplus talents will be distributed to the provincial dispatching power stations such as Dadu River." A relevant person of a Dadu River Basin power plant told reporters that the above special dispatching relationship has plunged Dadu River Hydropower consumption into "passivity".




So, with the delivery channel, will the problem of "waste water" be handled conveniently? AI Mingjian, director of the Economic Committee of the Sichuan provincial Party committee of the democratic construction of the people's Republic of China and a think tank expert of the Sichuan Power Association, thinks the answer is No. "Unlike the national dispatching station, which is directly sent out through UHV lines, Daduhe hydropower also faces the restriction of limited access in the province, that is, the capacity of access to the load center is constrained by the security of the power grid, and some sections are blocked."




AI Mingjian said that Sichuan Hydropower gathering is scattered in Ganzi, Ya'an and Panxi areas, and the supporting 500 kV transmission channel is the channel in the province. From the perspective of their own power transmission ability, these channels can theoretically complete the mission of power transmission. However, Sichuan power grid has built three circuit UHV DC lines to be responsible for the external transmission of Sichuan power, resulting in the problem of "strong DC and weak AC". In order to satisfy the safety and stability of Sichuan power grid, the transportation capacity of the above 500 kV transmission channel has to be limited in wet season. "Since the 13th five year plan, although the channels in the province have been continuously strengthened, the line is still blocked, and the capacity is still more than 4 million kilowatts. With the operation of hydropower stations under construction, the problem of lack of channels will be further highlighted."




AI Mingjian also said frankly that the obstruction of the channel not only makes the hydropower that should have been consumed in Sichuan Province have no way out, but also may lead to the dilemma of "no electricity for Chengdu and other load centers", and finally presents the power shortage of Sichuan power grid itself.




"Only by accelerating the construction of Sichuan UHV communication power grid can we truly improve the safety function of the power grid and fundamentally deal with the problem of 'waste water'"




How to solve the dilemma of "abandoning water"?




AI Mingjian said that as early as the 12th Five Year Plan period, the phenomenon of "strong direct and weak cross" of Sichuan power grid has attracted the attention of the industry, and relevant parts have carried out research and proof on this. However, until the end of the 13th five year plan, there is still no final conclusion on how to deal with it. Considering that during the 14th Five Year Plan period, three UHV DC channels will be put into operation in Sichuan, and the problem of "strong DC and weak AC" will continue to deteriorate. "Only by accelerating the construction of Sichuan UHV communication power grid can we truly improve the safety function of the power grid and fundamentally deal with the problem of waste water."




"To deal with the problem of 'waste water' in Dadu River is to deal with the problem of 'waste water' in Sichuan." According to a person from Guoneng Daduhe company, Sichuan is a clean hydropower power base of the national "west to East power transmission", but it does not constitute a matching power transmission channel and market consumption space. "It is advocated to confirm the scheme of Sichuan UHV communication power grid as soon as possible, classify it into the national plan of the 14th five year plan and implement it as soon as possible to solve the transmission bottleneck in the province; accelerate the planning and construction of transmission channels between Sichuan and East and central China, so as to provide a basic guarantee for hydropower transmission. Together, strengthen the implementation and supervision of clean power consumption mechanism, break down inter provincial barriers and complete the optimal allocation of hydropower resources in Sichuan on a larger scale."




Tan Hongen proposed that in addition to Sichuan's own needs, the power load in Chongqing will also increase rapidly with the rise of Chengdu Chongqing twin city economic circle as a national strategy. In the long run, the existing 500 kV power grid in Sichuan is increasingly more than enough in terms of overall power supply guarantee, hydropower transportation and saving channel occupation, so it is difficult to meet the development needs. In this regard, he advocated the planning of 1000 kV Chengdu Chongqing UHV power grid, improve the ability of surplus power transmission such as ABA area in the upper reaches of Dadu River, and directly transport a large amount of clean power to the load center or power grid outside the area, so as to prevent long-distance, large-capacity and relay transmission, so as to improve the economy, comprehensively deal with the problem of waste water, and jointly improve the ability of power supply guarantee in Chengdu and Chongqing.




The reporter learned that at the beginning of February this year, relevant parties have completed the evaluation opinions on the Sichuan Chongqing UHV communication grid scheme and will report it to the national power bureau. For the follow-up progress, this newspaper will continue to pay attention to it.




Comments | dealing with "waste water" should be done sooner rather than later




In recent years, the total amount of water crossing in the river basin has exceeded the serious problem of "increasing and not decreasing". As one of the top 13 hydropower development bases in China, the Dadu River Basin is endowed with good hydropower resources, close to the load center, and low power transportation cost. All development conditions are unique, but now it has become "the most severe River in the country to 'abandon water". It is just like that the Brazilian men's football team was screened in the group stage of the International Cup, which is incomprehensible and unbearable.




Unlike emerging industries such as wind power and photovoltaic power generation, the problem of power abandonment has only appeared in recent years. In the hydropower industry, "water abandonment" is by no means new. As early as around 2000, Sichuan Ertan Hydropower Station, which has just been put into operation, presented a large-scale planning of "abandoning water". This accident soon became the "fuse" for China to launch the power system reform in 2002, rewriting the development process of the whole power industry. From this perspective, the problem of "water abandonment" is not only a crisis of industrial development, but also a "grinding stone" to promote industrial development towards high-quality development. It is a severe opportunity for the in-depth reform of industrial system and mechanism. Power enterprises and relevant competent departments are not unfamiliar with "waste water", so they should have experience and talent to give scientific and useful treatment schemes.




However, in the decade of the 21st century, the problem of "waste water" which has disappeared for more than 10 years has revived and the situation is becoming more and more intense: the planning has rapidly increased from the initial billions of degrees per year to nearly 70 billion degrees in 2018. Although it has decreased in the past two years, the waste power remains at a high level of 30 billion degrees. Dealing with "waste water" has become the primary problem of hydropower industry.




The numbers are the most convincing. Taking the Three Gorges Hydropower Station as an example, in recent years, the annual average power generation of this hydropower station with the largest international installed capacity planning is only about 100 billion kwh, and the "waste water" planning of 70 billion kwh is equivalent to 2 / 3 of the power generation of the Three Gorges Hydropower Station, which has been wasted. Even according to the relatively small "abandoned water" plan of 30 billion kwh per year and the relatively low price level of 0.3 yuan / kWh, the direct economic loss of "abandoned water" power to relevant enterprises has been close to 10 billion yuan in 2020 alone. Among them, the "abandoned water" power of an enterprise of Guoneng Daduhe company has exceeded 40 billion kwh since 2015. Such a huge waste of resources must not be left unchecked. The problem of a large amount of "abandoned water" all year round needs to be effectively dealt with as soon as possible.




The "Huiliu River Basin" will be the first to abandon water in the "three main river basins in Sichuan Province" in the quarter of 2020, and the "Huiliu River Basin" will be the first to abandon water, accounting for about 35.7% of the "three main river basins" in the province ... the many roll calls at the press conference of the national power administration, which fully reminded the seriousness of the "water abandonment" problem of the Dadu River, also triggered a series of questions: why has the Dadu River become a "disaster area" compared with the year before? Is the construction of power supply too fast or the construction of transmission line too slow? Why is the harmonious work of severe engineering construction so inefficient? The problem of "abandoning water" has long been exposed. Why has it not changed over the years, but is it fading away? In addition to reporting the "abandoned water" situation, what measures have the competent authorities taken to deal with the problem? When can the problem be fundamentally solved?




No matter what the answer to this series of question marks is, dealing with the "abandoned water" of Dadu River is a "must answer" or even a "quick answer" that hydropower enterprises and relevant competent departments can't get around.




Dispose of "waste water" sooner rather than later. The earlier the problem is handled, the less water energy resources will be wasted, and the more economic losses will be recovered for the local, enterprises and even the country. The outcome of long-term delay can only be that all parties will lose. At a time when the "abandonment of wind" and "abandonment of light" have significantly improved, dealing with the problem of "abandonment of water" has become an inevitable requirement for the completion of high-quality development of hydropower industry. It is also an important starting point for China to complete the vision of "carbon peak" and "carbon neutralization", and it is also the responsibility of relevant competent departments.




In particular, hydropower development and the construction of supporting transmission projects are generally faced with problems such as wide project geographical span, large number of parts involved and great difficulty in overall planning and harmony. The relevant competent departments should make decisions as soon as possible and implement them as soon as possible. They should not always do nothing at the critical moment, so that the problem of "water abandonment" will not be solved for a long time and the precious clean and low-carbon power will be wasted.