Did you know that the world's largest electricity-generating plant generates a total electric capacity of 22.5 gigawatts (GW)?

The Three Gorges Dam is a hydroelectric gravity dam that spans the Yangtze River by the town of Sandouping, in Yiling District, Yichang, Hubei province, in central China, downstream of the Three Gorges. The Three Gorges Dam has been the world's largest power station in terms of installed capacity (22,500 MW) since 2012.

The dam generates an average 95±20 TWh of electricity per year, depending on annual amount of precipitation in the river basin. After the extensive monsoon rainfalls of 2020, the dam's annual production nearly reached 112 TWh, breaking the previous world record of ~103 TWh set by another large dam, the Itaipu Dam in 2016.

A large dam across the Yangtze River was originally envisioned by Sun Yat-sen in The International Development of China, in 1919. He stated that a dam capable of generating 30 million horsepower (22 GW) was possible downstream of the Three Gorges. In 1932, the Nationalist government, led by Chiang Kai-shek, began preliminary work on plans in the Three Gorges. In 1939, during the Second Sino-Japanese War, Japanese military forces occupied Yichang and surveyed the area. A design, the Otani plan, was completed for the dam in anticipation of a Japanese victory over China.

In 1944, the United States Bureau of Reclamation's head design engineer, John L. Savage, surveyed the area and drew up a dam proposal for the 'Yangtze River Project'. Some 54 Chinese engineers went to the U.S. for training. The original plans called for the dam to employ a unique method for moving ships: the ships would enter locks located at the lower and upper ends of the dam and then cranes would move the ships from one lock to the next. Groups of craft would be lifted together for efficiency. It is not known whether this solution was considered for its water-saving performance or because the engineers thought the difference in height between the river above and below the dam too great for alternative methods. Some exploration, survey, economic study, and design work was done, but the government, in the midst of the Chinese Civil War, halted work in 1947.

After the 1949 Communist Revolution, Mao Zedong supported the project, but began the Gezhouba Dam project nearby first, and economic problems including the Great Leap Forward and the Cultural Revolution slowed progress. After the 1954 Yangtze River Floods, in 1956, Mao Zedong wrote "Swimming", a poem about his fascination with a dam on the Yangtze River. In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.

During the 1980s, the idea of a dam reemerged. The National People's Congress approved the dam in 1992: out of 2,633 delegates, 1,767 voted in favour, 177 voted against, 664 abstained, and 25 members did not vote, giving the legislation an unusually low 67.75% approval rate.

Construction started on December 14, 1994. The dam was expected to be fully operational in 2009, but additional projects, such as the underground power plant with six additional generators, delayed full operation until May 2012. The dam body was completed in 2006. The ship lift was completed in 2015. The dam had raised the water level in the reservoir to 172.5 m (566 ft) above sea level by the end of 2008 and the designed maximum level of 175 m (574 ft) by October 2010.

The power plant of the dam project was completed and fully functional as of July 4, 2012, when the last of the main water turbines in the underground plant began production. Each main water turbine has a capacity of 700 MW. Coupling the dam's 32 main turbines with two smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam is 22,500 MW. The last major component of the project, the ship lift, was completed in December 2015.

As well as producing electricity, the dam is intended to increase the Yangtze River's shipping capacity. By providing flood storage space, the dam reduces the potential for floods downstream which have historically plagued the Yangtze Plain. In 1931, floods on the river caused the deaths of up to 4 million people. As a result, China regards the project as a monumental social and economical success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions. However, the dam has caused ecological changes including an increased risk of landslides. Because of that, the dam has been controversial both domestically and abroad.

Source: Wikipedia

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