Three Gorges Dam, China
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). In 2012, the amount of electricity the dam generated was similar to the amount generated by the Itaipu Dam. Except for a ship lift, the dam project was completed and fully functional as of July 4, 2012, when the last of the main turbines in the underground plant began production. Each main 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. As well as producing electricity, 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. Made of concrete and steel, the dam is 2,335 m long and the top of the dam is 185 metres 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 high above the rock basis. When the water level is at its maximum of 175 metres above sea level, which is 110 metres higher than the river level downstream, the dam reservoir is on average about 660 kilometres in length and 1.12 kilometres in width. It contains 39.3 km3 of water and has a total surface area of 1,045 square kilometres. On completion, the reservoir flooded a total area of 632 square kilometres of land, compared to the 1,350 square kilometres of reservoir created by the Itaipu Dam. Power generation is managed by China Yangtze Power, a listed subsidiary of China Three Gorges Corporation (CTGC) a Central Enterprise SOE administered by SASAC. The Three Gorges Dam is the world's largest capacity hydroelectric power station with 34 generators: 32 main generators, each with a capacity of 700 MW, and two plant power generators, each with capacity of 50 MW, making a total capacity of 22,500 MW. Among those 32 main generators, 14 are installed in the north side of the dam, 12 in the south side, and the remaining six in the underground power plant in the mountain south of the dam. The expected annual electricity generation will be over 100 TWh.
These images acquired along the Yangtze River (Sandouping town, Yiling District, Yichang, Hubei province, China), in a time window of 27 years by the Landsat 5 and 8 satellites, aim to show the Three Gorges Dam, a hydroelectric dam built in the stretch of the Yangtze River (Upper left image). Using this type of comparison it is possible to see the development of the project to build the dam. Another aim of these images is to promote the opportunity to download Landsat data through the ESA portals, where images captured every day are made available in near real time to the users and the scientific community. Landsat full resolution data products are freely available for immediate download at:  View Landsat 5 TM high resolution image (JPG 3 MB) View Landsat 8 OLI high resolution image (JPG 2.2 MB)
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