The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in Yiling District, Yichang, Hubei province, China. The Three Gorges Dam is the world’s largest power station in terms of installed capacity (22,500 MW). The dam is the largest operating hydroelectric facility in terms of annual energy generation. 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. The dam body was completed in 2006. 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 dam is intended to increase the Yangtze River’s shipping capacity and reduce the potential for floods downstream by providing flood storage space. The Chinese government regards the project as a historic engineering, social and economic success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions. However, the dam flooded archaeological and cultural sites and displaced some 1.3 million people, and is causing significant ecological changes, including an increased risk of landslides. The dam has been a controversial topic both domestically and abroad.
The dam is 2,335 m (7,661 ft) long and the top of the dam is 185 metres (607 ft) above sea level. The project used 27.2 million cubic metres of concrete (mainly for the dam wall), 463,000 tonnes of steel (enough to build 63 Eiffel Towers) and moved about 102.6 million cubic metres of earth. The concrete dam wall is 181 metres (594 ft) high above the rock basis.
When the water level is at its maximum of 175 metres (574 ft) above sea level, which is 110 metres (361 ft) higher than the river level downstream, the dam reservoir is on average about 660 kilometres in length and 1.12 kilometres (3,700 ft) in width. It contains 39.3 km3 of water and has a total surface area of 1,045 square kilometres (403 sq mi). On completion, the reservoir flooded a total area of 632 square kilometres of land.
The government estimated that the Three Gorges Dam project would cost 180 billion yuan (US$22.5 billion). By the end of 2008, spending had reached 148.365 billion yuan, among which 64.613 billion yuan was spent on construction, 68.557 billion yuan on relocating affected residents, and 15.195 billion yuan on financing. It is estimated that the construction cost will be recovered when the dam has generated 1,000 terawatt-hours of electricity, yielding 250 billion yuan. Full cost recovery is expected to occur ten years after the dam starts full operation.