Equipment Specs
Content
Languages

Itaipu Dam

From RitchieWiki

Projects > Dams

Itaipu Dam
The Itaipu Dam is a dam and hydroelectric power plant built on the Parana River, which borders Brazil and Paraguay in South America. Located 8.7 miles (14 km) north of the International Bridge, linking the cities of Foz do Iguacu, Brazil and Ciudad del Este, Paraguay.[1]

The name Itaipu is taken from a local isle that existed near the construction site. It means “singing stone” in the Guarani language.[2]

The dam is a product of a binational agreement between Brazil and Paraguay. It was intended to exploit the Parana River for hydroelectric power and the irrigation of crops, during a time when both nations were suffering droughts.[3]

Initial construction of the dam and powerhouse took place between 1975 and 1991 for a total cost of US$18 billion.[4] However, an additional two generating units were added in September 2006 and March 2007.

The dam is 4.8 mi (7.7 km) long and 643 feet (196 m) high. However, the dam is not one single superstructure, but instead is made of several types of dams joined together. The main dam is a hollow concrete gravity dam, and is flanked by rockfill and earthfill dams. There are 14 spillways with a total discharge rate of 80,860 cubic yards (62,200 m3) per second.[5]

The powerhouse, located at the toe of the dam, is 1,055 yards (968 m) long. It has a total of 20 generators with an installed capacity of 14,000 megawatts and is capable of producing 93.4 billion kilowatt hours. The powerhouse is more powerful than 10 nuclear power stations.[6] Meanwhile, it avoids the 67.5 million tons of carbon dioxide emissions that would be produced by coal power plants.[7]

The Itaipu Dam is currently the world’s largest hydroelectric dam, but will be overtaken by the Three Gorges Dam when it is completed in 2009. It is listed as one of the Seven Wonders of the Modern World, according to the American Society of Civil Engineers. A cover article of the North American magazine Popular Mechanics described the construction of the Itaipu Dam as a “labor of Hercules.”[8]

The engineers for the project were International Engineering Co. and Itaipu Binancional. Project feasibility studies and some design was performed by the U.S. company Morrison-Knudsen Corp., while Italy’s Electroconsult SpA acted as a technical coordinator. Brazilian and Paraguayan engineers handled most of the design and a consortium of local firms, known as Union-Conempa, built the project.

Contents

[edit] Construction History

[edit] Developing a Plan

The Ministers of Foreign Affairs of Brazil and Paraguay began negotiating what would become the Itaipu Dam during the 1960s. Together, they signed an agreement in 1966 declaring the mutual interest of both parties to study the possible exploitation of hydro resources of the Parana River. This document was called the “Ata do Iguacu,” or Iguacu Act.

In 1967, the Brazilian—Paraguayan Joint Technical Commission was established to carry out the study and development of the Parana River.

After the study was complete, the Itaipu Treaty was signed on April 26,1973 to go ahead with damming the river. However, it wasn’t until the group Itaipu Binancional was founded, on May 17, 1974, that the plan could move forward.

Itaipu Binacional was created to administrate the financing, construction, and management of the dam.

[edit] Diverting the River

Construction began in January 1975. Before any work could begin on the dam structure, workers had to divert the world’s seventh largest river. The Parana River’s average flow rate is 293,000 cubic feet (8,790 m3) per second.[9] It took three years to build the 1.3-mile (2.1-km) long, 300-foot (90-m) deep, 490-foot (147-m) wide diversion canal.[10] The Parana River’s path was officially changed on October 14, 1978.

Two cofferdams were built to provide a dry foundation for the dam construction site. Each cofferdam was 328 feet (98.4 m) high, 1,800 feet (540 m) long, and 148 feet (44.4 m) wide at the base.[11] They were rock embankments enclosing a clay core.

In total, approximately 50 million tons of earth and rock were excavated for the foundation and diversion canal.[12]

On October 19, 1979, the nations of Brazil, Paraguay, and Argentina signed an agreement, the Acordo Tripartite, outlining allowable river levels. At the time, all three countries were ruled by military dictatorships and Argentina was concerned of the power the dam created for Brazil and Paraguay. If a conflict occurred, Brazil or Paraguay could open the floodgates of the Itaipu Dam and flood Buenos Aires, Argentina.

[edit] Dam Construction

Dam construction was completed in the fall of 1982. The main structure is a hollow concrete gravity dam, which requires 35 percent less concrete than a solid gravity dam.[13] Still, 7.9 million cubic yards (6 million m3) of concrete was used.[14] It is connected to the spillways by a concrete buttress-type wing dam, which continues as a small Cardhfill dyke.

Monthly on-site concrete production reached 439,400 cu yd (338,000 m3)[15], while monthly average concrete placement on the dam, spillway and powerhouse was 365,552 cu yd (266,853 m3)[16]. The concrete were delivered by seven cableways fed by monorails from three large batch plants on each side of the dam. The six plants had a total production capacity of more than 1,400 cubic yards (1,022 m3) per hour.[17]

Construction also included eight rail-mounted tower cranes and five gantry cranes.

On October 13, 1982, the diversion canal closed and the Itaipu reservoir began taking on water. By the time the water reached the dam spillways, on October 27, it had risen 328 feet (100 m). The reservoir is 105 miles (170 km) long and contains 29 billion tons of water.

[edit] Hydroelectric Powerhouse

The hydroelectric power plant, housing the 18 generating units, was created using the slip form technique, allowing it to be completed five months ahead of schedule. All the upper portions above the embedded draft tube and penstock sections were slipformed instead of being cast-in-place, as was originally specified in the design.

The first generating unit of the hydroelectric powerhouse began running in December 1983.[18] However, it did not connect to Paraguay’s power grid until March 1984.[19] It connected to Brazil’s power grid five months later.

The first 18 Francis-type turbine units, measuring 53 feet (16.2 m) across[20], were installed at a rate of two or three per year until the final one became operational in March 1991. The original 18 units had a rated power of 715 megawatts[21] and total installed capacity of 12,600 megawatts, which was enough to power all of California or provide 78 percent of Paraguay’s energy supply and 25 percent of Brazil’s.[22]

Two more generators were added in 2006 and 2007. However, due to power constraints all 20 units were not allowed to be operational at the same time. The Acordo Tripartite limited the powerhouse to run no more than 18 units at once. So the additional two units simply allowed 18 generators to always be operational, while two could undergo maintenance.

Of the 18 original generating units, nine operate at 50 hertz to match the power grid frequency of Paraguay, while the other nine operate at 60 hertz to match the frequency of Brazil. Also, since Brazil is a much larger country, there is a power converter to transfer any excess power not used by Paraguay.

[edit] Displacement and Relocation

An estimated 10,000 locals were displaced by Itaipu Dam construction.[23] However some sources claim as many as four million people were relocated.[24] While many people relocated to nearby towns, some could not afford to purchase new land in Brazil, forcing many Brazilians to relocate to Paraguay where property was much cheaper.

[edit] Environmental Effects

At the outset of the project environmental concerns arose, including the dam’s impact on natural vegetation and a variety of animals.

The first measures of protection began with the formation of the Forest Inventory Committee in 1977. Its objective was to familiarize itself with the structure of local forest vegetation and the land affected by the Itaipu Dam. As a result of its studies five sub-projects for further study were established: forest management, forest exploitation, reforestation, forest soil and forest flora.

One specific action plan was the “Mymba Kuera Project,” which attempted to minimize the effects of reservoir flooding on fauna regions by catching animals and releasing them in biological reserves. The project was officially launched in 1977 and gathered 27,150 animals, including mammals, birds, reptiles, and insects.[25]

[edit] Equipment Used

[edit] Unique Facts

  • There was enough iron and steel used on the Itaipu Dam to construct 380 Eiffel Towers.
  • The foundation and diversion canal required 50 million tons of earth and rock to be excavated.
  • Approximately 40,000 people worked on construction.

[edit] References

  1. WonderClub.com The Itaipu Dam, 2008-09-24.
  2. SouthAmerica.cl Itaipu Dam, 2008-09-24.
  3. Cleveland, Cutler J.; Roman, Alexander. Itaipu Dam. The Encyclopedia of Earth, 2008-09-24.
  4. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  5. WonderClub.com The Itaipu Dam, 2008-09-24.
  6. Itaipu, 2008-09-24.
  7. Itaipu, 2008-09-24.
  8. WonderClub.com The Itaipu Dam, 2008-09-24.
  9. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  10. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  11. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  12. PBS. Wonders of the World databank: Itaipu Dam, 2008-09-24.
  13. PBS. Wonders of the World databank: Itaipu Dam, 2008-09-24.
  14. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  15. Itaipu, 2008-09-24.
  16. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  17. Engineering News Record Top 25 Years in ENR History: 1991, $18-billion Itaipu Dam Sets New Hydroelectric Records. ENR.com, November, 1999. (accessed: 2008-09-24)
  18. Itaipu, 2008-09-24.
  19. Itaipu, 2008-09-24.
  20. The Seven Wonders of the World: Itaipu Dam, 2008-09-24.
  21. Cleveland, Cutler J.; Roman, Alexander. Itaipu Dam. The Encyclopedia of Earth, 2008-09-24.
  22. PBS. Wonders of the World databank: Itaipu Dam, 2008-09-24.
  23. SouthAmerica.cl Itaipu Dam, 2008-09-24.
  24. Cleveland, Cutler J.; Roman, Alexander. Itaipu Dam. The Encyclopedia of Earth, 2008-09-24.
  25. American.edu Itaipu Dam, 2008-09-24.