Itaipu

From Freepedia

Itaipu (Guarani: Itaipu, Spanish: Itaipú; pronounced [itaj'pu]) is a dam that includes the largest hydroelectric power plant in the world. It is situated between Brazil and Paraguay along the Paraná River. The name "Itaipu" is derived from the Tupi Guarani language and means "singing stones".

The dam consists of concrete, rockfill, and earth, and is a total of 7.7 km wide. On average, 10651 m³/s of water drops from 220.3 m altitude to 100 m altitude above sea level, almost all of it through the 18 turbines in the powerplant. That drop releases an average of 12.36 gigawatts, or about 108 terawatt-hours each year. Of that total, the powerplant currently extracts about 90 terawatt-hours. Production is expected to gradually rise to just over 100 terawatt-hours per year as demand increases and two new generators are brought online.

The powerplant consists of 18 generator units of 700 MW (megawatts) each, allowing for a maximum output of 12,600 MW of power. Usually, one or at most two of the generators are off at any given time to allow for maintenance. The first generators started running in May 1984 and the final generator started running on April 9, 1991. Although it is not the largest dam in the world, it has the largest generating capacity and produces the most electricity. Its generating capacity (but not its annual production of electricity) will be surpassed by China's Three Gorges Dam. When the two new generators are finished in the first half of 2005, Itaipu will be capable of a total output of 14,000 MW of power.

It has been declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers.

Division between Brazil and Paraguay

Brazil and Paraguay each own half of the dam and half of the power produced, and each financed half of the construction costs. Paraguay sells the majority of its power to Brazil (and therefore has not had difficulty in paying for the project). Even in this configuration, the plant supplies 25% of the power consumed by Brazil and 90% of that consumed by Paraguay. Furthermore, the electricity for Paraguay is sold very cheaply and so, although it is poor, its citizens can afford abundant lighting. On the other hand, Itaipu was built during the corrupt Stroessner dictatorship and so a small number of families owning large construction businesses benefitted significantly at the expense of the general population.

Power transmission

The power generated by the generators on the Paraguay side is done at a frequency of 50 hertz, the grid frequency of Paraguay. The generators on the Brazilian side run with the grid frequency of Brazil, which is 60 hertz. Because Paraguay cannot consume all the energy produced by its generators, a part of it is transfered via the HVDC Itaipu to the area of São Paulo. The power generated by the Brazilian generators is transfered by 765 kV three phase AC lines to São Paulo.

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