My Simple Crib

The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in the Yiling District of Yichang, in Hubei province, China. It is the world’s largest electricity-generating plant of any kind. The dam body was completed in 2006. Except for a ship lift, the originally planned components of the project were completed on October 30, 2008 when the 26th generator in the shore plant began commercial operation. Each generator has a capacity of 700 MW.

Six additional generators in the underground power plant are not expected to become fully operational until 2011. Coupling the dam’s 32 main generators with 2 smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam will eventually reach 22.5 GW.

The project produces electricity, increases the river’s shipping capacity, and reduces the potential for floods downstream by providing flood storage space. From completion through September 2009 the dam has generated 348.4 TWh of electricity, covering more than one third of its cost.

The Chinese state regards the project as an 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 in China and abroad?.

The figure on the right faces upstream. The dam body in the middle left of the figure was divided into the left side (the right one-third of the dam body in this figure), the spillway (the middle of the dam body), and the right side (the left one-third of the dam body in this figure). The underground power plant under construction is to the left of the dam body, hidden in the mountains. The dam wall is made of concrete and is about 2,309 metres (7,575 ft) long, and 185 metres (607 ft) high. The wall is 115 metres (377 ft) thick on the bottom and 40 metres (131.2 ft) thick on top. The project used 27,200,000 cubic metres (35,600,000 cu yd) of concrete, 463,000 tonnes of steel, enough to build 63 Eiffel Towers, and moved about 102,600,000 cubic metres (134,200,000 cu yd) of earth. The ship lift is to the right of the dam body with its own designated waterway. The ship locks, which can be seen in the second figure, are to the right (northeast) of the ship lift.

When the water level is at its maximum of 175 metres (574 ft) over sea level (110 metres or 361 feet above the river level downstream), the dam reservoir is about 660 kilometres (410 mi) in length and 1.12 kilometres (0.70 mi) in width on average, and contains 39.3 km³ (31,900,000 acre·ft) of water. The total surface area of the reservoir is 1,045 km². The reservoir flooded a total area of 632 km² of land, compared to the 1,350 km² of reservoir created by the Itaipu Dam.

source:  Wikipedia