Three Gorges Dam Everything You Need to Know

Three Gorges Dam is the world’s largest dam in power generation capacity, built on the Yangtze River in the Hubei province of China. Its main wall is 2.3 kilometers long, and the height is 185 meters. Its installed productivity is the highest in the world, i.e., 22,500 MW, four times that of Tarbela Dam and more than eleven times that of Hover Dam. Before learning about how China built this engineering masterpiece, let’s look at its historical background.

Historical background of the dam:

The Yangtze River originates from Tibet and falls into the East China Sea off the coast of Shanghai. In terms of length. It is the third longest river in Asia, after the Nile and the Amazon Rivers. This river has historically been significant to the Chinese, but its floods have always brought a message of destruction to China.

Therefore, to end this disaster, a hundred years ago, in 1919, The President of China, Sun Yat Sen, gave the idea in his book The International Development of China that a large dam should be built on this river. Through this, flood control and electricity generation can be done. Initially, there was no work on his idea. But then, in 1931, what had been happening here for centuries. A new flood engulfed the region of the lower Yangtze River and killed hundreds of thousands of people, one of the five most devastating floods in human history.

Ongoing Debate:

To deal with this disastrous situation, initial work on the dam project began in 1932 during the tenure of China’s Nationalist Leader, Chiang Kai-shek. But this plan remained incomplete because in 1937, Japan invaded China, and this attack on Japan turned into an occupation. Work on the project was halted for some time, and then, in 1944, the Chinese government hired an American engineer for the Feasibility Study. He finished his work in 1946 and prepared a proposal for the dam’s construction. In his submission, the engineer also suggested that the dam be built using the lock system. However, the civil war in China halted the project once again.

At the end of the Civil War, the new Communist leader Mao Zedong took over the Chinese government in 1949. Then, in 1954, another flood of the Yangtze River devastated Wuhan and its adjoining areas, affecting about 20 million people. Maoze favored the Dong Dam, but he believed it was better to build small dams on the tributaries of the Yangtze River to deal with this situation before a mega dam. After the death of Mao, the idea of making the dam once again emerged in the 1980s. The Chinese government prepared a new team for the feasibility study, and a new proposal was also prepared. In 1992, the National People’s Congress finally approved the dam proposal. Friends, objections have also been raised on this dam for various reasons, which is why during the National People’s Congress voting, one-third of the members either voted against the dam or remained absent.

Construction of Three Gorges Dam

After the approval of the proposal, the initial preparations for the dam’s construction started in 1993. The Chinese company The China Three Gorges Corporation constructed this dam. The dam’s construction was formally inaugurated in 1994 and completed in two phases.

In the first phase, a temporary wall was constructed by stopping the water flow on one side of the river so that the dam’s main wall could be started in the landing part of this wall. Along this wall, water flowed from the rest of the river, and shipping continued. After the construction of the temporary fence, the first part of the main wall of the river dam, during which land was excavated and built for the two-way ship locks for the movement of ships. The first phase was completed in 2003. 14 turbines of 7700 MW were also installed in the same phase. Upon completion of the first phase, the temporary wall was demolished by blasting, and the process of water flow from the leading fence and testing was started. A turbine installed in the first phase of the dam also started generating electricity in 2003. After completing the first phase, the second phase was to begin.

Second Phase:

In the second phase, a temporary wall was constructed on the other side of the river flow, with the first phase building a wall and work on the second part of the main wall starting. This phase was completed in 2006. In this part of the main wall, 12 more turbines of 700 MW were installed. The total number of turbines along the border increased to 26. In addition, 8 more turbines were installed underground outside the dam wall. By the time the main wall was completed in 2006, 14 turbines of the first phase were fully functional, and electricity was being produced at full capacity. Now, the stage was to fill the dam. In this stage, the dam started to fill with water, and by 2007, the water level in the dam had reached 156 meters. And the turbines of the second stage were also becoming functional.

In 2009, the final testing phase began, filling the dam with water to its maximum height of 175 meters. In 2010, the dam was completed. Now, all the dam testing stages have been examined very closely. In this phase, ship locks, spillways, and all turbines were thoroughly tested. In 2012, when all the units were fully functional, the dam started generating electricity at full capacity.

Production Capacity of Three Gorges Dam

The dam features turbines manufactured by French, German, and Chinese companies, with a total of 34 turbines installed. The first installation phase included 14 turbines, each with a generating capacity of 700 MW. The second phase involved the installation of 12 turbines along the wall, with a production capacity of 700 MW each. The remaining 8 turbines include 6 underground turbines with a capacity of 700 MW and 2 with a capacity of 500 MW. This impressive setup gives the dam a total electricity generation capacity of 22,500 MW, making it the highest hydropower project in the world. The Itaipu Dam, located on the border of Brazil and Paraguay, is the second-highest dam in the world with a capacity of 14,000 MW. In comparison, the three gauges in the dam generate power four times more than Pakistan’s largest Tarbela Dam, which has a capacity of 4,888 MW.

The dam generates an average of 95 terawatts of electricity annually, while the electricity generated from it is transmitted through 500 kV transmission lines. A large portion of its production goes to cities in central China and east China, including Shanghai.

The water reservoir built by the construction of the Three Gorges Dam has a storage capacity of 39 billion cubic meters, and its total area is about 1100 square kilometers. Its storage capacity is three times more than Tarbela. The Three Gorges Dam ranks fifth in the world regarding water storage capacity.

How is shipping done?

The Yangtze River has always been important for maritime trade. A five-step, two-way lock system has also been constructed for navigation. The working of the locks is such that the ship from Shanghai in the east comes close to the dam and enters the first step of the lock, like the Panama Canal Locks. The water level is raised in the lock here, and thus, the ship reaches the next step. In doing so, the ship enters the dam and continues its journey westwards after crossing the fifth and final step. In the same way, if a loaded ship is going towards Shanghai, it enters the lock at the end of the dam. This time, the ship is lowered into the river by the water level being lowered. A ship of up to 10,000 tons can easily pass through The Locks. Friends, a ship takes 4 hours to fall out of unlocks. Chinese engineers have made an alternative here: the hydraulic ship lift. It was built in 2015. The lift takes a ship down the river and from the dam or dam to the river in 40 minutes.

Total Cost and Financing

The total cost of the dam was initially estimated at US$22 billion, but by the time it was completed, about “US$37 billion” had been spent on it. Of the total cost, $19 billion is on dam construction, $5 billion on power transmission, and about $13 billion on resettlement for migrants. Friends, this project of China was state-sponsored, and the money was obtained from various sources, including loans from the Three Gorges Development Fund and China Development Bank.

The dam generates about $8 billion in electricity annually since 2012. In this sense, the dam’s construction cost has also almost been recovered.

Objections

It is not new to raise objections to hydroelectric dams wherever they are built worldwide. But friends, this dam is also very controversial because about 1500 villages, cities, and towns were submerged in its Water Reservoir, and about “thirteen million people had to be evacuated”. Not only this but some archaeological sites were also submerged. This is why many national and international human rights organizations have expressed serious concerns about the dam’s construction in the past and continue to do so today.

After this, another objection is made that China has built such a big dam in the fault line region if there is ever an earthquake, etc., then the destruction caused by the collapse of the dam will be more severe than the monsoon flood situation, and the region of the lower Yangtze River will be severely affected.

A third objection is that the dam has severely affected wildlife, and landslides have increased in nearby areas.

Of all these objections, what was most focused on was the evacuation of people, but China has always maintained that the long-term benefits of this dam will reduce the short-term effects over time. With the completion of this green and renewable energy project, china’s annual coal consumption has been reduced by about “fifty million tons,” which is obviously very useful for the environment.

Interesting Information about Three Gorges Dam:

As we know, the capacity of this dam to generate electricity is 22,500 MW. But after heavy monsoon rains in 2020, the dam set a new record for annual electricity production, generating 112 terawatts. Earlier, this record was held by the world’s second largest Itaipu Dam. Itaipu Dam produced 103 terawatt hours of electricity in 2016. This year, the dam was completely flooded. Many experts also feared the dam’s main wall would be broken due to the flood.

The last interesting thing about the dam that NASA scientists have reported is that due to this great dam, our earth’s speed around its axis has decreased, but this change of less than a million parts of a second is so minor that it cannot be felt, or it does not matter.