Three Gorges Dam
The Three Gorges Dam (simplified Chinese: 三峡大坝; traditional Chinese: 三峽大壩; pinyin: Sānxiá Dàbà) is a hydroelectric gravity dam that spans the Yangtze River near Sandouping in Yiling District, Yichang, Hubei province, central China, downstream of the Three Gorges. The world's largest power station in terms of installed capacity (22,500 MW),[5][6] the Three Gorges Dam generates 95±20 TWh of electricity per year on average, depending on the amount of precipitation in the river basin.[7] After the extensive monsoon rainfalls of 2020, the dam's annual production reached nearly 112 TWh, breaking the previous world record of ~103 TWh set by Itaipu Dam in 2016.[8][9]
Three Gorges Dam
三峡大坝
China
Flood control, power, navigation
Operational
December 14, 1994
2003[1]
China Yangtze Power (subsidiary of China Three Gorges Corporation)
181 m (594 ft)
2,335 m (7,661 ft)
40 m (131 ft)
115 m (377 ft)
27.2 million m3 (35.6 million cu yd)
116,000 m3/s (4,100,000 cu ft/s)
39.3 km3 (31,900,000 acre⋅ft)
1,000,000 km2 (390,000 sq mi)
1,084 km2 (419 sq mi)[3]
600 km (370 mi)[4]
175 m (574 ft)
2003–2012
Conventional
Rated: 80.6 m (264 ft)
Maximum: 113 m (371 ft)[3]
32 × 700 MW
2 × 50 MW Francis-type
22,500 MW
45%
三峡大坝
Three Gorges Great Dam
Sānxiá Dàbà
Sānxiá Dàbà
ㄙㄢ ㄒㄧㄚˊ ㄉㄚˋ ㄅㄚˋ
сань ся да ба
The dam's body was completed in 2006; the power plant was completed and fully operational by 2012,[10][11] when the last of the main water turbines in the underground plant began production. Each of the main water turbines has a capacity of 700 MW.[12][13] Combining the capacity of the dam's 32 main turbines with the two smaller generators (50 MW each) that provide power to the plant itself, the total electric generating capacity of the Three Gorges Dam is 22,500 MW.[12][14][15] The last major component of the project, the ship lift, was completed in 2015.[16]
In addition to generating electricity, the dam was designed to increase the Yangtze River's shipping capacity. By providing flood storage space, the dam reduces the potential for flooding downstream, which 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,[17] with the design of state-of-the-art large turbines[18] and a move toward limiting greenhouse gas emissions.[19] However, the dam has led to some ecological changes, including an increased risk of landslides,[20][21] which have made it controversial domestically and abroad.[22][23][24][25]
Economics[edit]
The Chinese government estimated that the Three Gorges Dam project would cost 180 billion yuan (US$22.5 billion).[42] By the end of 2008, spending had reached 148.365 billion yuan, of which 64.613 billion yuan was spent on construction, 68.557 billion yuan on relocating affected residents, and 15.195 billion yuan on financing.[43] It was estimated in 2009 that the cost of construction would be fully recouped when the dam had generated 1,000 terawatt-hours (3,600 PJ) of electricity, yielding 250 billion yuan; total cost recovery was thus expected to be completed ten years after the dam became fully operational.[42] In fact, the entire cost of the Three Gorges Dam was recovered by December 20, 2013.[44]
Funding sources include the Three Gorges Dam Construction Fund, profits from the Gezhouba Dam, loans from the China Development Bank, loans from domestic and foreign commercial banks, corporate bonds, and revenue from both before and after the dam had become fully operational. Additional charges were assessed as follows: every province receiving power from the Three Gorges Dam had to pay an extra ¥7.00 per MWh, and the other provinces had to pay an additional charge of ¥4.00 per MWh. No surcharge was imposed on the Tibet Autonomous Region.[45]
Displacement of residents[edit]
During planning, it was estimated that 13 cities, 140 towns and 1,350 villages would be partially or completely flooded by the reservoir,[141][142][143] amounting to roughly 1.5% of Hubei's 60.3 million people and Chongqing Municipality's 31.44 million people.[144] These people were moved to new homes by the Chinese government, which considered the displacement justified by the flood protection provided for the communities downstream of the dam.[145]
Between 2002 and 2005, Canadian photographer Edward Burtynsky documented the impact of the project on the surrounding areas, including the town of Wanzhou.[146][147] Other photographers who recorded the change include Chengdu-based Muge,[148] Paris-based Zeng Nian (originally from Jiangsu),[149] and Israeli Nadav Kander.[150] Living conditions deteriorated for many, and hundreds of thousands of people could not find work. The older generation was particularly affected, but younger generations benefited from the educational and career opportunities afforded by moving to large cities with new, modern companies and schools.[151]
Some 2007 reports claimed that Chongqing Municipality would encourage four million more people to move away from the dam to Chongqing's main urban area by 2020.[152][153][154] The municipal government asserted that the relocation was driven by urbanization, rather than a direct result of the dam project, and that the people involved included other areas of the municipality.[155]
By June 2008, China had moved 1.24 million residents as far as Gaoyang in Hebei Province,[156] and the moves concluded the following month.[142]
Other effects[edit]
Cultural and history[edit]
The area which would fill with water behind the dam included locations with significant cultural history.[31]: 206 The State Council authorized a ¥505 million archaeology salvage effort.[31]: 206 Over the course of several years, archaeologists excavated 723 sites and conducted surface archaeology recovery missions at an additional 346 sites.[31]: 206 Archaeologists recovered 200,000 artifacts of which 13,000 were considered as particularly historically or culturally notable.[31]: 206 As part of this effort, the old Chongqing City Museum was replaced by the Chongqing China Sanxia Museum to house many of the recovered artifacts.[31]: 206
Recovered structures that were too large for museums were moved upland to reconstruction districts (fu jian qu), which are outdoor museum parks. Recovered structures placed in such parks include temples, pavilions, houses, and bridges, among others.[31]: 206
Some sites could not be moved because of their location, size, or design, such as the hanging coffins site high in the Shen Nong Gorge, part of the cliffs.[157]
National security[edit]
The United States Department of Defense reported that in Taiwan, "proponents of strikes against the mainland apparently hope that merely presenting credible threats to China's urban population or high-value targets, such as the Three Gorges Dam, will deter Chinese military coercion".[158] Destroying the Three Gorges Dam has been a tactic discussed and debated in Taiwan since the early 1990s, when the dam was still in the planning phase.[159] The notion that the military in Taiwan would seek to destroy the dam provoked an angry response from the mainland Chinese media. People's Liberation Army General Liu Yuan was quoted in the China Youth Daily saying that the People's Republic of China would be "seriously on guard against threats from Taiwan independence terrorists".[160] Former Taiwanese Ministry of Defense advisor Sung Chao-wen, called the notion of using cruise missiles to destroy the Three Gorges Dam "ridiculous", saying missiles would deliver minimal damage to the reinforced concrete, and any attack attempts would have to go through multiple layers of ground and air defenses.[161][162]
The Three Gorges Dam is a steel-concrete gravity dam. The water is held back by the innate mass of the individual dam sections. As a result, damage to an individual section should not affect other parts of the dam.[159] Zhang Boting, deputy secretary-general of China Society for Hydropower Engineering, suggested that concrete gravity dams such as the Three Gorges Dam are resistant to nuclear strikes.[163]
Debate among Chinese scholars and analysts about the basic principles of China's no first use of nuclear weapons policy includes whether to include narrow exceptions, such as acts that produce catastrophic consequences equivalent to that of a nuclear attack, including attacks intended to destroy the Three Gorges Dam.[164][165]
Structural integrity[edit]
Immediately after the reservoir was first filled, around 80 hairline cracks were observed in the dam's structure.[166][167][168] Still, an experts group gave the project overall a good-quality rating.[169] The 163,000 concrete units all passed quality testing, with normal deformation within design limits.