The Three Gorges Project, which officially started construction on December 14, 1994 and was completed on May 20, 2006, has been used for nearly 15 years, and has won the world's water conservancy project with a total installed capacity of 22.4 million kW and a designed annual power generation capacity of 84.7 billion hours.
Three Gorges Project
However, from planning, survey, design to completion and production, the Three Gorges Project has been controversial, some people are worried about the quality of the project, some people are worried about the problem of life expectancy, and some people are worried about economic benefits..... So how long does the Three Gorges Dam live? Built 15 years ago, has the huge amount of 250 billion yuan spent on it been recovered?
The functional "lifespan" of the Three Gorges Dam
In fact, the relevant departments have long given the answer, the design function of the Three Gorges Dam "lifespan" is 150 years, but many people still do not believe this answer.
In fact, the Three Gorges Dam mainly relies on the weight of the dam body to resist upstream water pressure and other loads, so the use of the "life" of the Three Gorges Dam depends mostly on the concrete volume and quality of the dam. The dam has a concrete work volume of 27.94 million m³, which translates into a concrete pipe with a diameter of 1 meter that can circle the Earth's equator.
Construction scene of the Three Gorges Project
So far, the total amount and intensity of concrete pouring of the Three Gorges Dam, the length of 6km double-line five-level locks, and the installed capacity of 22.4 million kW of power stations are the first in the world.
The concrete mass is enough, but what about the quality? The quality of concrete is actually a core issue considered by the three gorges project builders. In order to pass the quality of the concrete of the dam, the designers used the first-class fly ash with excellent performance as a concrete admixture for the first time to optimize the amount of concrete raw material and the mix ratio, and the unit dosage of the selected large-volume concrete mix ratio was only about 90kg/m³, reaching the world's leading level.
Secondly, the designers introduced the most advanced foreign dam pouring equipment top belt machine to optimize the concrete pouring scheme. Finally, the designers pioneered the secondary air cooling technology of concrete aggregate, which ensures a high level of construction quality in all aspects of concrete temperature control.
Thanks to the adoption of the above series of world-leading technologies and innovative solutions, the concrete pouring quality of the Three Gorges Project has been far ahead of the world's advanced level.
Rapid concrete construction arrangement of the second phase of the Three Gorges Dam
From the above content, it can be seen that there is no problem with the concrete volume and quality of the Three Gorges Project, which can reach its 150-year design "lifespan". However, when the dam was accepted, many cracks as thin as hair were still found, which could not help but worry that when the Three Gorges Dam encountered huge disasters such as the Wenchuan earthquake and the Kanto earthquake in Japan, these cracks would become the last straw that overwhelmed the camel and triggered a huge disaster.
earthquake
According to Lu Youlin, then general manager of the Three Gorges Project Development Corporation of the Yangtze River, the tiny cracks in the Three Gorges Dam were only between 0.1 and 0.2 millimeters. In fact, under the existing technical conditions, any dam will have cracks, and these cracks caused by the excessive temperature difference between the inside and outside of the concrete pouring process have been effectively treated, and will never affect the functional "life" of the dam.
Schematic diagram of the Three Gorges Dam
The use of the Three Gorges Dam "lifespan"
Unlike the lifespan of people, the "lifespan" of a dam is divided into functional "lifespan" and the use of "lifespan". For example, the life determined by the mass and quality of the concrete poured dam mentioned above is the functional "life", and the "life" lost in the process of use after the dam is completed is the use of "life".
Location map of the Three Gorges Dam and important cities along the Yangtze River
Then many people will be afraid, because in this way, the functional "lifespan" of the dam is the longest time the dam can theoretically last. In the process of use, it is inevitable that other factors will affect the dam, thereby shortening the life of the dam, so more people are "justified" to worry that the Three Gorges Dam will not be able to support for a hundred years.
In fact, the use of the "life" of the dam can be extended, and the "life" of the dam can be extended after each reinforcement and investment in the dam. Just like when we buy a mobile phone, we can constantly repair and upgrade it to achieve the purpose of extending the use of "life", and this is true of many dams in the world, and the same is true of the Three Gorges Dam.
Is there a definitive conclusion about the "lifespan" of the Three Gorges Dam?
The determinant of the "life" of the dam is still in concrete, and the internationally recognized life of the concrete dam is 50 years, but the concrete material has a history of more than 200 years from its discovery to the present, and there is still no accurate conclusion or detection of how long its life cycle is.
History of concrete materials
We can only know that there are more than 5,000 dams in operation in the world for more than 50 years, and now the Three Gorges uses the most advanced technology, and there is no reason for lifespan. As long as it is still safely serving us, by 200, 300, 500 or even 1000 years, the answer is not so important.
Can the three gorges dam pay for itself?
As the world's largest hydropower project - the Three Gorges Dam, its cost is also a staggering 250 billion yuan, of which the total investment of the project reached 95.46 billion yuan, including 50.09 billion yuan of hub projects, 30.07 billion yuan of resettlement fees and 15.3 billion yuan of power transmission and transformation projects. The dynamic investment of the Three Gorges Dam has also reached 160 billion.
Spending such a huge amount of money, it has been built and operated for 15 years now, can it really be recovered? Let's take a closer look at the analysis:
As a hydropower project, the electricity economy is undoubtedly the main source of income. The Three Gorges Dam has 26 700,000-kilowatt units with a total installed capacity of 22.4 million kilowatts, and has been operating stably and efficiently for 15 consecutive years. By 2021, the cumulative power generation capacity of the Three Gorges Power Station will reach 1.14 trillion kWh, and the average transmission price of the Three Gorges Power transmission will be 0.3 yuan / kWh, so the electricity revenue of the Three Gorges Dam in 15 years will be roughly 342 billion yuan.
The Right Bank Power Station of the Three Gorges Project transmits power transmission lines outside the power station
The shipping efficiency of the Three Gorges Dam is also extremely impressive. Before the Three Gorges Dam was filled in 2003, due to various constraints such as dry water and shallow water, the one-way transportation volume was only 10 million tons. Since the storage of water in 2003, the scale of the waterway in the reservoir area has increased significantly; the conditions below Fuling with many curves, shallow waters and dangerous beaches have been fundamentally improved, and day and night navigation has been realized, the water flow has slowed down, and the river surface has become wider.
Gezhouba Project
The dry water flow of the waterway below Gezhouba has increased significantly, the safety of ship transportation on the Sichuan River has been significantly improved, and the cost of ship transportation has been significantly reduced.
These five major improvements have increased the traffic volume by nearly 15 times, and in 2017, the freight volume reached 15.739 million tons. This benefit cannot be measured in monetary terms, and the benefit is directly proportional to time.
freight
After the completion of the Three Gorges Dam, it will become the first batch of 5A-class scenic spots in China and the first batch of demonstration sites for industrial tourism zones in China. In 2019, the number of tourists received by the Three Gorges Dam Tourist Area exceeded 3 million for the first time, reaching 3.2 million. By 2020, the Three Gorges Dam Tourist Area has received a total of 30.24 million tourists since its opening in 1997, and the tourism revenue is expected to be as much as 10 billion yuan.
Three Gorges Dam Tourist Area
The Three Gorges Dam also has a very important strategic position in the flood control system of the Yangtze River. Flood disasters have always been a major problem for us, after the completion of the Three Gorges Dam, it has a flood control reservoir capacity of 22.15 billion m³, which can flexibly cope with flood disasters in the middle and lower reaches of the Yangtze River at any time. The storage capacity of more than 20 billion cubic meters has fundamentally changed the flood control situation in the middle and lower reaches of the Yangtze River.
Map of the water changes in the Sandouping section of the Yangtze River before and after the completion of the Three Gorges Dam
As we all know, once the flood disaster occurs, the direct economic losses of cities in the middle and lower reaches of the Yangtze River are easily as high as hundreds of millions of yuan, and the flood control effect in the past 15 years can reach at least 10 billion yuan in terms of revenue.
The Three Gorges Dam has huge environmental benefits by replacing thermal power with clean, cheap and renewable water resources. Flue gas pollution (sulfur dioxide, nitrogen oxides) produced by conventional thermal power is the main inducement for the formation of acid rain. Traditional thermal power will also produce a large amount of dust, and dust pollution will have a huge adverse impact on human life and plant growth.
acid rain
The environmental impact caused by the above two points of pollution is huge, and the data show that after the completion of the Three Gorges Dam, it has reduced the emission of harmful gases such as 130 million tons of carbon dioxide, 3 million tons of sulfur dioxide and 15,000 tons of sulfur monoxide every year, which has greatly improved the living environment of people around the Yangtze River and also provided help for biodiversity, and this benefit cannot be estimated.
The completion of the Three Gorges Dam has solved the employment problem of many people, effectively enhanced the economy of the original Three Gorges Reservoir Area, brought talents and technology to the Three Gorges Reservoir Area, accelerated the construction of urbanization, and played a great role in promoting the development of the secondary and tertiary industries in the Reservoir Area. How can these gains be measured in monetary terms?
Beautiful Three Gorges Dam
In summary, the huge amount of 250 billion yuan spent on the completion of the Three Gorges Dam has been recovered long ago, and there are many gains that cannot be measured in money. With the passage of time, the economic benefits generated by the Three Gorges Dam will only increase, and for the cities in the middle and lower reaches of the Yangtze River, and even for the whole of China, the completion of the Three Gorges Dam will be beneficial and harmless.