The name "Itaipu" was taken from an island that existed near the construction site. In theGuarani language,Itaipu means "the sounding stone."[2] As of 2020, the Itaipu Dam's hydroelectric power plant produced the second-largest amount of electricity of any hydroelectric power plant in the world, with its electricity production being only surpassed by theThree Gorges Dam plant in China. Additionally, Itaipu also holds the45th largest reservoir in the world.
With its construction completed in 1984, it is a binational undertaking run by Brazil and Paraguay at the border between the two countries, 15 km (9.3 mi) north of theFriendship Bridge. The project ranges fromFoz do Iguaçu, in Brazil, andCiudad del Este in Paraguay, in the south toGuaíra andSalto del Guairá in the north. The installed generation capacity of the plant is 14 GW, with 20 generating units providing 700 MW each with a hydraulic design head of 118 metres (387 ft). In 2016, the plant employed 3038 workers.[3]
Of the twenty generator units currently installed, ten generate at 50 Hz for Paraguay and ten generate at 60 Hz for Brazil. Since the output capacity of the Paraguayan generators far exceeds the load in Paraguay, most of their production is exported directly to the Brazilian side, from where two600 kV HVDC lines, each approximately 800 kilometres (500 mi) long, carry the majority of the energy to theSão Paulo/Rio de Janeiro region where the terminal equipment converts the power to 60 Hz.
The concept behind the Itaipu Power Plant was the result of serious negotiations between the two countries during the 1960s. The "Ata do Iguaçu" (Iguaçu Act) was signed on July 22, 1966, by the Brazilian and Paraguayan Ministers of Foreign Affairs,Juracy Magalhães andRaúl Sapena Pastor. This was a joint declaration of the mutual interest in studying the exploitation of the hydro resources that the two countries shared in the section of the Paraná River starting from and including theSalto de Sete Quedas, to theIguaçu River watershed. The treaty that gave origin to the power plant was signed in 1973.
The terms of the treaty, which expired in 2023, have been the subject of widespread discontent in Paraguay. The government of President Lugo vowed to renegotiate the terms of the treaty with Brazil, which long remained hostile to any renegotiation.[4][5]
In 2009, Brazil agreed to a fairer payment of electricity to Paraguay and also allowed Paraguay to sell excess power directly to Brazilian companies instead of solely through the Brazilian electricity monopoly.[6][7]
In 1970, theconsortium formed by the companies ELC Electroconsult S.p.A. (from Italy) andIECO (from the United States)[8] won the international competition for the realization of the viability studies and for the elaboration of the construction project. Design studies began in February 1971. On April 26, 1973, Brazil and Paraguay signed the Itaipu Treaty, the legal instrument for the hydroelectric exploitation of the Paraná River by the two countries. On May 17, 1974, the Itaipu Binacional entity was created to administer the plant's construction. The construction began in January of the following year. Brazil's (and Latin America's) first electric car was introduced in late 1974; it received the nameItaipu in honor of the project.[9]
The construction of the dam was first contested byArgentina, but the negotiations and resolution of the dispute ended up setting the basis for Argentine–Brazilian integration later on.[10]An important diplomatic settlement was reached with the signing of theAcordo Tripartite by Brazil, Paraguay, and Argentina, on October 19, 1979. This agreement established the allowed river levels and how much they could change as a result of the various hydroelectric undertakings in the watershed that was shared by the three countries.
Thereservoir began its formation on October 13, 1982, when the dam works were completed and the side canal's gates were closed. Throughout this period, heavy rains and flooding accelerated the filling of the reservoir as the water rose 100 meters (330 feet) and reached the gates of thespillway on October 27.[citation needed]
On May 5, 1984, the first generation unit started running in Itaipu. The first 18 units were installed at the rate of two to three a year; the last two of these started running in the year 1991.
The last two of the 20 electric generation units started operations in September 2006 and in March 2007, thus raising the installed capacity to 14 GW and completing the power plant. This increase in capacity allows 18 generation units to run permanently while two are shut down for maintenance. Due to a clause in the treaty signed between Brazil, Paraguay, and Argentina, the maximum number of generating units allowed to operate simultaneously cannot exceed 18 (see theagreement section for more information).
The rated nominal power of each generating unit (turbine and generator) is 700 MW. However, because thehead (difference between reservoir level and the river level at the bottom of the dam) that actually occurs is higher than the designed head (118 m or 387 ft), the power available exceeds 750 MW half of the time for each generator.Each turbine generates around 700 MW; by comparison, all the water from theIguaçu Falls would have the capacity to feed only two generators.
On November 10, 2009, transmission from the plant was completely disrupted, possibly due to a storm damaging up to three high-voltage transmission lines.[11] Itaipu itself was not damaged. This caused massive power outages in Brazil and Paraguay, blacking out the entire country of Paraguay for 15 minutes, and plunging Rio de Janeiro and São Paulo into darkness for more than 2 hours. 50 million people were reportedly affected.[12] The blackout occurred at 22:13 local time. It affected the southeast of Brazil most severely, leavingSão Paulo,Rio de Janeiro, andEspírito Santo completely without electricity. Blackouts also swept through the interior ofRio Grande do Sul,Santa Catarina,Mato Grosso do Sul,Mato Grosso, the interior ofBahia, and parts ofPernambuco, energy officials said.[13] By 00:30, power had been restored to most areas.
Panoramic view of the Itaipu Dam, with the spillways (closed at the time of the photo) on the left
This diagram shows in detail the heights:
325 metres (1,066 ft), entire dam including the 100 metres (330 ft) high Power Line 4 Pylons atop the Barrage 260 metres (850 ft), dam + the foundation inside water until the river floor 247 metres (810 ft), 196 metres (643 ft) high of roof reinforcement concrete dam + Cranes atop the Barrage 225 metres (738 ft), Elevation End Main Concrete Barrage
196 metres (643 ft), The official roof given from Itaipú Binacional Webpage
When construction of the dam began in 1971, approximately 10,000 families living beside theParaná River were displaced because of the construction.[15][16]
The world's largest waterfall by volume, theGuaíra Falls, was inundated by the newly formed Itaipu reservoir. The Brazilian government later liquidated the Guaíra Falls National Park. A few months before the reservoir was filled, 80 people died when an overcrowded bridge overlooking the falls collapsed, as tourists sought a last glimpse of the falls.[17]
The Guaíra Falls was an effective barrier that separated freshwater species in the upper Paraná basin (with its manyendemics) from species found below it, and the two are recognized as differentecoregions.[18] After the falls disappeared, many species formerly restricted to one of these areas have been able to invade the other, causing problems typically associated withintroduced species. For example, more than 30 fish species that formerly were restricted to the region below the falls have been able to invade the region above.[18]
The American composerPhilip Glass has written a symphoniccantata namedItaipu in honor of the structure.
The total volume of excavation of earth and rock in Itaipu is 8.5 times greater than that of theChannel Tunnel, while the volume of concrete is 15 times greater.
Around forty thousand people worked in the construction.[20]
The total length of the dam is 7,235 metres (23,737 ft). The crest elevation is 225 metres (738 ft). Itaipu is actually four dams joined together – from the far left, an earth fill dam, a rock fill dam, a concretebuttress main dam, and a concrete wing dam to the right.
The spillway has a length of 483 metres (1,585 ft).
The maximum flow of Itaipu's fourteen segmentedspillways is 62.2 thousand cubic metres per second (2.20×10^6 cu ft/s), into three ski slope-formed canals. It is equivalent to 40 times the average flow of the nearby naturalIguaçu Falls.
The flow of two generators (700 cubic metres per second (25,000 cu ft/s) each) is roughly equivalent to the average flow of the Iguaçu Falls (1,500 cubic metres per second (53,000 cu ft/s)).
The dam is 196 metres (643 ft) high, equivalent to a 65-story building.[21]
Though it is the seventh largest reservoir in size in Brazil, the Itaipu'sreservoir has the highest ratio of electricity production to flooded area. For the 14,000 MW installed power, 1,350 square kilometres (520 sq mi) were flooded. The reservoirs for the hydroelectric power plants ofSobradinho Dam,Tucuruí Dam,Porto Primavera Dam,Balbina Dam,Serra da Mesa Dam, andFurnas Dam are all larger than the one for Itaipu, but have a smaller installed generating capacity. The one with the next largest hydroelectric production, Tucuruí, has an installed capacity of 8,000 MW, while flooding 2,430 km2 (938 sq mi) of land.
Electricity is 55% cheaper when made by the Itaipu Dam than by the other types of power plants in the area.
Although its designed peak generating capacity is only 14,000 MW, behind the 22,500 MWThree Gorges Dam, the dam formerly held the record for energy production with 101.6 TWh produced in 2016. This record was beaten in 2020, when the Three Gorges Dam produced a new record 111.8 TWh after extensive monsoon rainfall that year.[22]
In the period 2012–2021, the Itaipu Dam maintained the second-highest average annual hydroelectric production in the world, averaging 89.22 TWh per year, second to the 97.22 TWh per year average of the Three Gorges Dam in that period.
