Itaipu Dam

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. 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.[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, the consortium formed by the companies ELC Electroconsult S.p.A. (from Italy) and IECO (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 name Itaipu in honor of the project.[9]

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.

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.[10] 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 dam undergoes expansion work.

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.

• The course of the seventh biggest river in the world was shifted, as were 50 million tonnes of earth and rock.
• The amount of concrete used to build the Itaipu Power Plant would be enough to build 210 football stadiums the size of the Estádio do Maracanã.
• The iron and steel used would allow for the construction of 380 Eiffel Towers.
• The volume of excavation of earth and rock in Itaipu is 8.5 times greater than that of the Channel Tunnel and the volume of concrete is 15 times greater.
• Around forty thousand people worked in the construction.[20]
• Itaipu is one of the most expensive objects ever built.

• 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 concrete buttress 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 segmented spillways is 62.2 thousand cubic metres per second (2.20×10^⁶ cu ft/s), into three skislope formed canals. It is equivalent to 40 times the average flow of the nearby natural Iguaçu 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's reservoir has the best relation between electricity production and 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 of Sobradinho Dam, Tucuruí Dam, Porto Primavera Dam, Balbina Dam, Serra da Mesa Dam and Furnas 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 the other types of power plants in the area.

Inside the dam structure

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.[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.