The Paulo Afonso Hydroelectric Complex (Complexo Hidrelétrico de Paulo Afonso), also known as the Paulo Afonso Complex, is a system of three dams and five

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

power plant A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

s on the

São Francisco River The São Francisco River (, ) is a large Rivers of Brazil, river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil (after the Amazon R ...

near the city of Paulo Afonso in

Bahia Bahia () is one of the 26 Federative units of Brazil, states of Brazil, located in the Northeast Region, Brazil, Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo (state), São Paulo, Mina ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. The complex exploits an natural gap on the river, known as the Paulo Afonso Falls. Constructed in succession between 1948 and 1979, the dams support the Paulo Afonso I, II, III, IV and Apollonius Sales (Moxotó) power plants which contain a total of 23 generators with an installed capacity of . PA I was the first large power plant constructed in Brazil and the complex constitutes the densest area of dams in Brazil. The complex provides electricity to areas in northeastern Brazil and is the main tourist attraction in the region.

Background and history

On January 23, 1913, the 1.1 MW Angiquinho Hydroelectric Plant, built by

industrialist A business magnate, also known as an industrialist or tycoon, is a person who is a powerful entrepreneur and investor who controls, through personal enterprise ownership or a dominant shareholding position, a firm or industry whose goods or ser ...

Delmiro Gouveia, was the first use of the Paulo Afonso Falls for power production and the first hydroelectric power plant in northeastern Brazil. Construction of the power plant was intended to spur economic growth in the area and soon after another hydroelectric plant was constructed upstream near Petrolândia. By the 1940s Brazil's Ministry of Agriculture recognized the importance of harnessing the

for economic development in the semi-arid region. They began to plan the river's development and the Companhia Hidro-Elétrica do São Francisco ( CHESF) was formed in 1945. On May 23, 1944, construction on Paulo Afonso I had been authorized with two generators. Construction began in 1948; workers and engineers experienced difficulty diverting the river, transporting the turbines to the site while in midst of dangerous work conditions. Tunnels and a cavern had to be excavated for Brazil's first underground power plant. Due to the depth and strength of the river near the falls, it was not diverted until 1954. On January 15, 1955, Brazilian President João Café Filho inaugurated PA I. Previously, in 1953, CHESF negotiated with the government for a third generating unit at PA I and the excavation of another underground power plant for the future PA II adjacent to PA I on the falls. The third generator at PA I was commissioned on September 18, 1955, and construction of PA II began that year as well. By 1961, PA II was complete and on October 24 that year, its first generator was commissioned. PA II's five other generators became operational between 1962 and December 18, 1967. Construction on PA III started soon after in 1967 and was complete in 1971 with its first generator commissioned on October 21 that year. Another generator was commissioned in 1972 and the final two in 1974, the last of which on August 5. In 1971, construction had moved to the Apollonius Sales (Moxotó) Dam and power plant upstream from the falls. In 1977, construction was completed and its four generators went online in April of that year. In 1972, construction began on the final dam and power plant, PA IV, southwest of the falls. Construction was complete in 1979 and its first generator commissioned on December 1. Two more generators were commissioned in 1980, two in 1981 and the final on May 28, 1983. Construction of the dams caused a loss of of land along with displacing 52,000 people.

Specifications

Apolônio Sales (Moxotó)

The Apolônio Sales Dam and power plant were originally known as Moxotó but were renamed after Apolônio Sales, the founder of CHESF. The dam is a high, long rock and earth-fill

embankment dam An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface ...

. The dam creates a capacity reservoir with a surface area of and catchment area of . The dam and its reservoir are primarily intended to regulate water flow to PA I, II and III 4 km downstream. On the dam's west side, it supports a 20 floodgate

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

with a capacity. The power plant is located on the east side of the dam near the reservoir's shore and contains four generators, each with Kaplan turbines. Each generator has a

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity,

Paulo Afonso I, II, III

Situated directly on top of the Paulo Afonso Falls, the Delmiro Gouveia Dam supports Paulo Afonso I, II and III. The dam is high, long and is a concrete gravity type. The reservoir formed by the dam has a capacity and surface area of . The dam has one uncontrolled spillway and a controlled spillway on its outer linings while also supporting four controlled spillways on the front of the falls. These four surface spillways when open, discharge water below and essentially recreate the falls. All three power plants are about underground and adjacent to one another. PA I lies in the center and is housed in a long, high and wide cavern. It contains three generators with

Francis turbine The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The pro ...

s, for an installed capacity of . The generators are Vertical Sync-type and were manufactured by Westinghouse. The turbines were manufactured by Dominion Engineering Works. PA II is a long, high and wide power house. It contains six Vertical Sync-type generators with Francis turbines. Two of the generators are , one is and the remaining three are , for a total installing capacity of MW. The generators were manufactured by S. Morgan Smith and

Hitachi () is a Japanese Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1910 and headquartered in Chiyoda, Tokyo. The company is active in various industries, including digital systems, power and renewable ener ...

while the turbines by Voith. PA III's power house is long, high and wide. It contains four Vertical Sync-type generators manufactured by

Siemens Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the positi ...

for an installed capacity of . Each generator utilizes a Francis turbine manufactured by Voith.

Paulo Afonso IV

The Paulo Afonso Dam located southwest of the falls is high and long. The dam is an earth and rock-fill type but is in length of concrete structures which include the power plant's intake and the spillway. The spillway is composed of eight floodgates and has a maximum discharge capacity of . The dam withholds a capacity reservoir with a surface area of . The reservoir receives water through a channel that originates near the southern end of the Appolonius Sales Reservoir and continues south, skirting the city. The PA IV power house is also underground and is long, high and wide. It contains six MW generators for an installed capacity of . Each generator is a SíncronoVertical-type manufactured by Siemens and utilizes vertical shaft Francis turbines that were manufactured by Voith.

References

External links

CHESF - Paulo Afonso Hydroelectric Complex
{{Webarchive, url=https://web.archive.org/web/20110706160248/http://www.chesf.gov.br/portal/page/portal/chesf_portal/paginas/sistema_chesf/sistema_chesf_geracao/conteiner_geracao?p_name=8A2EEABD3BDFD002E0430A803301D002 , date=2011-07-06 Dams in Bahia Dams on the São Francisco River Energy infrastructure completed in 1955 Energy infrastructure completed in 1967 Energy infrastructure completed in 1974 Energy infrastructure completed in 1983 Energy infrastructure completed in 1977 Underground power stations 1955 establishments in Brazil Paulo Afonso