Snowy Owl
Retired in 2010, In Memoriam
The Three Gorges Dam (simplified Chinese: 长江三峡大坝; traditional Chinese: 長江三峽大壩; pinyin: Ch?ngjiāng Sānxi? D? B?) is a Chinese hydroelectric river dam that spans the Yangtze River in Sandouping, Yichang, Hubei, China.
The total electric generating capacity of the dam will reach 22,500 megawatts,[1] at which point it will be the largest hydro-electric power station in the world. This is the biggest project that has been undertaken in China since the Great Wall and the Grand Canal. Several generators are yet to be installed; the dam is not expected to become fully operational until about 2011.[2]
As with many dams, there is a debate over costs and benefits. Although there are potential economic benefits such as flood control and hydroelectric power, there are also concerns about the relocation of over 1,500,000 people[citations needed]who have been or will be displaced by the rising waters; siltation that could limit the dam's useful life; loss of numerous valuable archaeological and cultural sites; and the significant adverse effects of increased pollution upon the regional ecosystem.[3]
Project history
The dam was originally envisioned by Sun Yat-sen in The International Development of China in 1919.[4] [5]
In 1944, involvement from the United States began when the Bureau of Reclamation engineer J.L. Savage surveyed the area and drew up a dam proposal. Around 54 Chinese engineers were sent to the U.S. for training.
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.[6]
After the 1949 communist victory, the leader Mao Zedong supported the project, but the Gezhouba Dam project was begun first and economic problems including The Great Leap Forward and the Cultural Revolution slowed progress.
In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.[7]
During the 1980s plans were revived.
Pushed through by Li Peng, the dam was approved by the National People's Congress in 1992, there were a record number of abstentions and dissenting votes.
The construction started on December 14, 1994.[8] The dam was expected to be fully operational in 2009, but due to additional projects such as the underground powerplant with 6 additional generators, and due to the complexity of the ship lift, the dam is not expected to become fully operational until about 2011.[7]
Scale of the project
The dam wall is made of concrete and is about 2,309 metres (7,575 ft) long, and 101 metres (331 ft) high.
The wall is 115 metres (377.3 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 metric tons of steel, enough to build 63 Eiffel Towers, and moved about 102,600,000 cubic metres (134,200,000 cu yd) of earth.[9]
When the water level is maximum at 175 metres (574 ft) over sea level (91 metres (299 ft) above river level) , the reservoir created by the Three Gorges Dam is about 660 kilometres (410 mi) in length and 1.12 kilometres (0.70 mi) in width on average, and contains 39.3 cu km (9.43 cubic miles) of water.
The total surface area of the reservoir is 1045 sq km. The reservoir will flood total area of 632 sq km of land comparing to 1,350 sq km of the reservoir created by the Itaipu Dam.
Comparing to Lake Superior, the Three Gorges Dam reservoir is longer than the lake(560 km), 1.1 % of the surface area of Lake superior(82,400 sq km) and about 1/700 of the volume of the lake(28700 cu km).[10]
The dam will raise the water level the third time to its designed maximium water level(175m above sea level) by the end of 2008.[11]
Economics
When finished, the project will have cost 180 billion yuan, over 20 billion yuan less than the initial estimated budget of 203.9 billion yuan, just under 30 billion USD.
This is because the calculation accounts for the effect of inflation, and the lower costs are attributed to a low inflation rate in recent years.[12] It is estimated that the cost of construction will be recovered when the dam generates 1000 TWh of the electricity, which will be sold at the price of 250 billion yuan. This will take 10 more years after the dam starts full operation.[4]
Sources for funding include the Three Gorges Dam Construction Fund, revenue from Gezhouba Dam, policy loans from the China Development Bank, loans from domestic and foreign commercial banks, corporate bonds, and revenue from Three Gorges Dam before and after it is fully operational, with additional charges for electricity contributing to the Three Gorges Construction Fund.
The additional charges are as follows: Every province receiving power from the Three Gorges Dam has to pay an additional charge of ?7.00 per MWh. Provinces that will not receive power from the Three Gorges Dam have to pay an additional charge of ?4.00 per MWh. Tibet does not have to pay any additional money.[13]
Power distribution
The electricity generated by the Three Gorges Dam project is sold to the State Grid Corporation and China South Power Grid Corporation at a rate of ?250 per MWh ($35.7 US). Nine provinces and two cities consume the power from it, including Shanghai.[21]
The power distribution and transmission of the Three Gorges Dam project cost about 34.387 billion Yuan. It was completed in December 2007, one year ahead of time.[22]
Power is sent in three directions. The 500 kV DC transmission line to the East China Grid has a capacity of 7,200 MW. There are three 500 kV DC transmission lines: HVDC Three Gorges-Shanghai(3,000 MW), HVDC Three Gorges-Changzhou(3,000 MW) and HVDC Gezhouba - Shanghai(1,200 MW).
The 500 kV AC transmission line to Central China Grid has a capacity of 12,000 MW. The other 500 kV DC transmission line HVDC Three Gorges-Guangdong to South China Grid has a capacity of 3,000 MW and supplies Guangdong.[23]
In the original plan, it was expected to provide 10% of electricity consumption in China. However, China?s demand for electricity has increased at a higher rate than was planned, and if fully operational now, it would support about 3% of the total electricity consumption in China.[24]
http://en.wikipedia.org/wiki/Environmental_issues_with_the_Three_Gorges_Dam
The total electric generating capacity of the dam will reach 22,500 megawatts,[1] at which point it will be the largest hydro-electric power station in the world. This is the biggest project that has been undertaken in China since the Great Wall and the Grand Canal. Several generators are yet to be installed; the dam is not expected to become fully operational until about 2011.[2]
As with many dams, there is a debate over costs and benefits. Although there are potential economic benefits such as flood control and hydroelectric power, there are also concerns about the relocation of over 1,500,000 people[citations needed]who have been or will be displaced by the rising waters; siltation that could limit the dam's useful life; loss of numerous valuable archaeological and cultural sites; and the significant adverse effects of increased pollution upon the regional ecosystem.[3]
Project history
The dam was originally envisioned by Sun Yat-sen in The International Development of China in 1919.[4] [5]
In 1944, involvement from the United States began when the Bureau of Reclamation engineer J.L. Savage surveyed the area and drew up a dam proposal. Around 54 Chinese engineers were sent to the U.S. for training.
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.[6]
After the 1949 communist victory, the leader Mao Zedong supported the project, but the Gezhouba Dam project was begun first and economic problems including The Great Leap Forward and the Cultural Revolution slowed progress.
In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.[7]
During the 1980s plans were revived.
Pushed through by Li Peng, the dam was approved by the National People's Congress in 1992, there were a record number of abstentions and dissenting votes.
The construction started on December 14, 1994.[8] The dam was expected to be fully operational in 2009, but due to additional projects such as the underground powerplant with 6 additional generators, and due to the complexity of the ship lift, the dam is not expected to become fully operational until about 2011.[7]
Scale of the project
The dam wall is made of concrete and is about 2,309 metres (7,575 ft) long, and 101 metres (331 ft) high.
The wall is 115 metres (377.3 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 metric tons of steel, enough to build 63 Eiffel Towers, and moved about 102,600,000 cubic metres (134,200,000 cu yd) of earth.[9]
When the water level is maximum at 175 metres (574 ft) over sea level (91 metres (299 ft) above river level) , the reservoir created by the Three Gorges Dam is about 660 kilometres (410 mi) in length and 1.12 kilometres (0.70 mi) in width on average, and contains 39.3 cu km (9.43 cubic miles) of water.
The total surface area of the reservoir is 1045 sq km. The reservoir will flood total area of 632 sq km of land comparing to 1,350 sq km of the reservoir created by the Itaipu Dam.
Comparing to Lake Superior, the Three Gorges Dam reservoir is longer than the lake(560 km), 1.1 % of the surface area of Lake superior(82,400 sq km) and about 1/700 of the volume of the lake(28700 cu km).[10]
The dam will raise the water level the third time to its designed maximium water level(175m above sea level) by the end of 2008.[11]
Economics
When finished, the project will have cost 180 billion yuan, over 20 billion yuan less than the initial estimated budget of 203.9 billion yuan, just under 30 billion USD.
This is because the calculation accounts for the effect of inflation, and the lower costs are attributed to a low inflation rate in recent years.[12] It is estimated that the cost of construction will be recovered when the dam generates 1000 TWh of the electricity, which will be sold at the price of 250 billion yuan. This will take 10 more years after the dam starts full operation.[4]
Sources for funding include the Three Gorges Dam Construction Fund, revenue from Gezhouba Dam, policy loans from the China Development Bank, loans from domestic and foreign commercial banks, corporate bonds, and revenue from Three Gorges Dam before and after it is fully operational, with additional charges for electricity contributing to the Three Gorges Construction Fund.
The additional charges are as follows: Every province receiving power from the Three Gorges Dam has to pay an additional charge of ?7.00 per MWh. Provinces that will not receive power from the Three Gorges Dam have to pay an additional charge of ?4.00 per MWh. Tibet does not have to pay any additional money.[13]
Power distribution
The electricity generated by the Three Gorges Dam project is sold to the State Grid Corporation and China South Power Grid Corporation at a rate of ?250 per MWh ($35.7 US). Nine provinces and two cities consume the power from it, including Shanghai.[21]
The power distribution and transmission of the Three Gorges Dam project cost about 34.387 billion Yuan. It was completed in December 2007, one year ahead of time.[22]
Power is sent in three directions. The 500 kV DC transmission line to the East China Grid has a capacity of 7,200 MW. There are three 500 kV DC transmission lines: HVDC Three Gorges-Shanghai(3,000 MW), HVDC Three Gorges-Changzhou(3,000 MW) and HVDC Gezhouba - Shanghai(1,200 MW).
The 500 kV AC transmission line to Central China Grid has a capacity of 12,000 MW. The other 500 kV DC transmission line HVDC Three Gorges-Guangdong to South China Grid has a capacity of 3,000 MW and supplies Guangdong.[23]
In the original plan, it was expected to provide 10% of electricity consumption in China. However, China?s demand for electricity has increased at a higher rate than was planned, and if fully operational now, it would support about 3% of the total electricity consumption in China.[24]
http://en.wikipedia.org/wiki/Environmental_issues_with_the_Three_Gorges_Dam