Represa de Itaipú
Barragem de Itaipu
|Official name||Central Hidroeléctrica Itaipú Binacional|
Usina Hidrelétrica Itaipu Binacional
|Location||Foz do Iguaçu|
|Construction began||January 1971|
|Opening date||5 May 1984|
|Construction cost||US$19.6 billion (equivalent to $48.8 billion today)|
|Owner(s)||Government of Brazil & Government of Paraguay|
|Dam and spillways|
|Type of dam||Combination gravity, buttress and embankment sections|
|Height||196 m (643 ft)|
|Length||7,919 m (25,981 ft)|
|Dam volume||12,300,000 m3 (430,000,000 cu ft)|
|Spillway capacity||62,200 m3/s (2,200,000 cu ft/s)|
|Total capacity||29 km3 (24,000,000 acre?ft)|
|Catchment area||1,350,000 km2 (520,000 sq mi)|
|Surface area||1,350 km2 (520 sq mi)|
|Maximum length||170 km (110 mi)|
|Maximum width||12 km (7.5 mi)|
|Hydraulic head||118 m (387 ft)|
|Turbines||20 × 700 MW (940,000 hp) Francis-type|
|Installed capacity||14 GW (19,000,000 hp)|
|Annual generation||96.586 TWh (347.71 PJ) (2018)|
The Itaipu Dam (Portuguese: Barragem de Itaipu, Spanish: Represa de Itaipú; Portuguese pronunciation: [it?j'pu], Spanish pronunciation: [itaj'pu]) is a hydroelectric dam on the Paraná River located on the border between Brazil and Paraguay. The construction of the dam was first contested by Argentina, but the negotiations and resolution of the dispute ended up setting the basis for Argentine-Brazilian integration later on.
The name "Itaipu" was taken from an isle that existed near the construction site. In the Guarani language, Itaipu means "the sounding stone". The Itaipu Dam's hydroelectric power plant produced the second most electricity of any in the world as of 2020, only surpassed by the Three Gorges Dam plant in electricity production.
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 the Friendship Bridge. The project ranges from Foz do Iguaçu, in Brazil, and Ciudad del Este in Paraguay, in the south to Guaíra and Salto 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.
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 two 600 kV HVDC lines, each approximately 800 kilometres (500 mi) long, carry the majority of the energy to the São 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 and Raúl Sapena Pastor, respectively. 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, the Salto de Sete Quedas, to the Iguaçu River watershed. The treaty that gave origin to the power plant was signed in 1973.
The terms of the treaty, which expires 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.
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.
In 1970, the consortium formed by the companies ELC Electroconsult S.p.A. (from Italy) and IECO (from the United States) 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 name Itaipu in honor of the project.
On October 14, 1978, the Paraná River had its route changed, which allowed a section of the riverbed to dry so the dam could be built there.
An important diplomatic settlement was reached with the signing of the Acordo 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 hydroelectrical undertakings in the watershed that was shared by the three countries.
The reservoir 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 the spillway on October 27.
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 the agreement section for more information).
The rated nominal power of each generating unit (turbine and generator) is 700 MW. However, because the head (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 the Iguaçu 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. 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. The blackout hit at 22:13 local time. It affected the southeast of Brazil most severely, leaving São Paulo, Rio de Janeiro and Espírito Santo completely without electricity. Blackouts also swept through the interior of Rio Grande do Sul, Santa Catarina, Mato Grosso do Sul, Mato Grosso, the interior of Bahia and parts of Pernambuco, energy officials said. By 00:30 power had been restored to most areas.
The world's largest waterfall by volume, the Guaíra Falls, was inundated by the newly formed Itaipu reservoir. The Brazilian government later liquidated the Guaíra Falls National Park, and blasted away the submerged rock face where the falls had been, facilitating safer navigation, thus eliminating the possibility of restoring the falls in the future. 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.
The Guaíra Falls was an effective barrier that separated freshwater species in the upper Paraná basin (with its many endemics) from species found below it, and the two are recognized as different ecoregions. After the falls disappeared, many species formerly restricted to one of these areas have been able to invade the other, causing problems typically associated with introduced 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.
Although its designed peak generating capacity is only 14,000 MW, behind the 22,500 MW Three 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.
In the period 2010-2019, the Itaipu Dam maintained the highest average annual hydroelectric production in the world averaging 92.7 TWh per year, higher than the 91.9 TWh per year average of the Three Gorges Dam in that period.