This hydroelectric plant has an installed power of 22,500 megawatts. The total capacity of the 90 hydroelectric plants in Colombia is about 18,000 megawatts.
Photo: Daniel Felipe Rodríguez Rincón
One day in 1956, Mao Tse-tung wrote a poem after taking a dip in the Yangtze River, the largest river in China and the third largest in the world: “the stone walls will rise against the current (…) / To contain The clouds and rain of Mount Wu and the narrow gorges will become a lake.”
The verses written by who, in the end, would become the patriarch of the People’s Republic of China, refer to an old dream of the time: to build a large dam that would contain the waters of the Yangtze and, in this way, calm the constant floods. that affected riverside communities.
The idea would materialize until 1993, when the construction of an unprecedented infrastructure in modern history began: the Three Gorges.
Three Gorges, four purposes
After more than two decades of works, 27 million cubic meters of concrete, 463,000 tons of steel (enough to build about 60 Eiffel towers), 102.6 million cubic meters of land and, incidentally, more than 1 .2 million people displaced and subsequently relocated, China built what remains today the largest water retention work in the world.
In principle, the works on the Yangtze River were intended to control floods in an area where historically catastrophic episodes occur, on average, once every ten years. One of the most affected areas is in the middle course of the Yangtze, between the cities of Yichang and Wuhan, the area where the dam is precisely located.
In the flood season in 2020 alone, five floods occurred in the Yangtze River basin, with the largest flood peak reaching 75,000 cubic meters per second.
After a 67% approval in the Chinese legislature, engineers took on the task of definitively raising those “stone walls” that Mao mentioned to contain the liquid of the powerful tributary that crosses much of the geography of the Asian giant.
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Figures provided by the Chinese Government indicate that, to date, the Three Gorges can contain 22 billion cubic meters of water that, when overflowing in the past, hit 15 million people and ruined nine million hectares of land.
But taming this runaway horse called the Yangtze River has another advantage: harnessing its strength to drive turbine blades and, in this way, producing useful energy for an economic apparatus so dependent on industrial capacity.
Hence, the Three Gorges is also the largest hydroelectric plant in the world.
As explained by Wang Hai, deputy director of the Operation Administration of the Three Gorges Corporation (TGC), in addition to flood control and power generation, this work also facilitates the transit of ships on the Yangtze River and the exploitation of resources. water.
“Three Gorges generation already supplies 50% of all China’s energy expenditure. It can meet the demand in central, eastern and southern China. “It has changed the entire landscape of China’s energy system,” says Wang.
And since the dam opened a passage for ships in June 2023, the volume it loads has increased rapidly. Annually, more than 1.5 billion tons of cargo cross the Three Gorges, with goods such as cars produced in Yichang.
The hydroelectric plant concentrates 42,000 million tons of water in an area of about 600 square kilometers.
Photo: Daniel Felipe Rodríguez Rincón
The strength of the colossus
In a country of approximately 1.4 billion inhabitants, according to 2024 figures, the Three Gorges hydroelectric plant provides enough energy for half of the national consumption, thanks to 34 turbines (the last two installed in 2022), whose blades are moved thanks to the 750,000 cubic meters of water that cross them every second.
The technical sheet indicates that this hydroelectric plant has an installed power of 22,500 megawatts. To see it in perspective, the largest plant of this type in Colombia, the El Guavio Hydroelectric Power Plant (in Ubalá, Cundinamarca), has an installed capacity of 1,260 megawatts, as indicated by Enel.
And if the net effective generation capacity (the energy produced with the reservoirs at their maximum capacity) of the nearly 90 hydroelectric plants in Colombian territory that feed the National Interconnected System (SIN) is added, an approximate figure of 18,000 is obtained. megawatts.
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In 2014, the Three Gorges surpassed the Itaipú hydroelectric plant, between Brazil and Paraguay, in electrical energy production, establishing a new world record for this type of plants. That year, Chinese infrastructure produced 98.8 million megawatt hours (mWh).
The intention, again, is not to compare pears with apples – or “throats” in this case – but the parallels make it easier to have a mental image of this colossus that literally changed the course of the Earth.
There are physicists who maintain that the weight of water concentrated by the Three Gorges hydroelectric plant in a relatively small area acts as a heavy suitcase for the planet’s rotation.
More precisely, it is said that 42,000 million tons concentrated in an area of about 600 square kilometers They managed to move the Earth’s axis of rotation two centimeters, something that only earthquakes or tides do, making days 0.06 thousandths of a second longer around the world.
Among other effects, critics of the project have criticized the changes suffered by the habitats of endemic species in the region, such as the baiji or white-finned dolphin (declared extinct in 2006) and the environmental degradation during the filling of the dam.
Not in vain, the environmental protection efforts led by the Chinese authorities have allowed, to date, the levels of pollution in the waters of the Yangtze to be minimal. In fact, on the coasts of the city of Yichang it is common to see entire families devoting themselves to informal fishing of crabs and prawns for their own consumption.
The conjunction of water flows (the Qutang, Wu and Xiling gorges, which give the project its name) makes the hydroelectric potential of this body of water one of the most important in the world.
Photo: Daniel Felipe Rodríguez Rincón
The irony of hydroelectric plants today
The same nature that has served human beings to illuminate their development is playing against hydroelectric generation, which usually plays a key role in the energy matrix of many countries.
Climate change and, specifically, the increase in global temperature has led dams around the world to face a common problem: the reduction in water levels. An irony that, currently, sets off alarms because it threatens the energy production that industries and homes need daily.
According to XM data, in the midst of the El Niño phenomenon, so far in April 2024 the value of the SIN’s water reserves approached 31% of the useful volume for energy generation. According to Fedesarrollo analysis, the above marks the “lowest figure in the last 24 years.”
“This situation implies significant challenges in terms of electricity prices, while raising concerns about possible scenarios of water and electricity shortages,” Fedesarrollo indicated in a report published last Thursday, May 2.
Monitoring the behavior of dams is especially important because nearly 70% of the installed electrical energy capacity in Colombia corresponds to energy from water sources, as Acolgen points out.
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On the other side of the world, the effects of the El Niño Phenomenon are beginning to worry the authorities who, for the moment, have taken measures to combat droughts in agricultural regions in the southwest of the country, being the provinces of Yunnan and Sichuan (whose capital, Chengdu , is considered the world capital of pandas) the most affected.
However, in the Asian giant they insist that dams like the Three Gorges will emerge ahead of the high temperatures that are being recorded in the middle of the spring season. We will have to wait for what happens during the summer.
The director of the Three Gorges explained to this newspaper that the hydroelectric plant does not suffer droughts because from September to December, periods in which rainfall on the Yangtze River increases, it accumulates its reserves.
“From December until next summer, which is the driest time, the doors are opened for the waters to come out. So we control the amount of water so as not to create droughts or floods,” says Wang.
To the above, we must add that the Yangtze River has natural conditions that put it in a good position against droughts. For example, most of its basin has abundant rainfall, with precipitation of 1,100 mm per year. Furthermore, the conjunction of water flows (the Qutang, Wu and Xiling gorges, which give their name to the project) makes the hydroelectric potential of this body of water one of the most important in the world.
*Special envoy of El Espectador in China
