The Belo Monte Dam is a hydroelectric complex on the lower Xingu River, a southern tributary of the Amazon, in the state of Pará in northern Brazil. With 11,233 MW installed, it is the second-largest hydroelectric plant in Brazil after Itaipu and the fifth-largest in the world. Its first turbine began generating on 5 May 2016, and the eighteenth and last main unit went in during November 2019. Because the Xingu shrinks sharply in the dry season, its guaranteed output is only about 4,571 MW. The project also diverts up to 80% of the river's flow away from a 100 km stretch called the Volta Grande ("Big Bend"), and it displaced more than 20,000 people, and it has been fought over on the river and in Brazil's courts since the 1980s.
Norte Energia, Eletrobras and BNDES: Who Built and Paid for It
Belo Monte belongs to Norte Energia S.A., a consortium that won the government auction on 20 April 2010 with a bid of R$77.97 per megawatt-hour, almost 6% under the ceiling price of R$83. Big builders including Odebrecht and Camargo Corrêa had pulled out before the auction, saying the price was too low to earn a return. That left the state in charge. Eletrobras controls 49.98% of Norte Energia directly and through its subsidiaries Eletronorte (19.98%) and CHESF (15%), and Eletronorte operates the plant. Other partners include investment funds, the pension fund Funcef and construction firms such as OAS, Queiroz Galvão and Mendes Junior.
President Luiz Inácio Lula da Silva signed the concession in Brasília on 26 August 2010, and Belo Monte became a flagship of his Growth Acceleration Programme. Estimates put the dam at more than US$16 billion, plus about US$2.5 billion for transmission lines. Most of the money came from the Brazilian Development Bank (BNDES) and from the pension funds Petros, Previ and Funcef. Up to a third of the official cost was to be covered by incentives using public money. In February 2011 Norte Energia ordered its machinery: IMPSA was to supply four Francis turbine units, Andritz three Francis units plus the six bulb turbines, and Alstom seven Francis units in a deal worth US$682.3 million.
The workforce came from all over Brazil. The impact studies forecast 18,700 direct jobs and another 25,000 indirect ones, but most of them would disappear once building ended. Labour relations were tense. In April 2012 a regional judge declared a planned strike illegal and warned that workers would be fined R$200,000 a day if they stayed away.
Tuíre, Raoni and the 1989 Altamira Gathering
The people who stopped the dam the first time were the Kayapó. Eletronorte began surveying the Xingu in 1975 under the military government, and a 1979 study by the engineering consortium CNEC proposed five dams on the Xingu and one on its tributary the Iriri. The first, called Kararaô, would have flooded about 1,225 km². When the plans became public in 1987, the region's Indigenous nations organised the First Encounter of the Indigenous Nations of the Xingu in Altamira in 1989.
At that meeting Tuíre Kayapó, then 19, held her machete against the face of the Eletronorte engineer José Antonio Muniz Lopes. The photograph travelled around the world. Afterwards the five upstream dams were dropped from planning, and Kararaô was renamed Belo Monte at the request of the Kayapó. Tuíre spent the following decades campaigning against the project and died on 10 August 2024. The older Kayapó chief Raoni Metuktire, born in 1932, became the international face of the opposition. After the 2010 auction he warned that "there will be a war" to keep outsiders off Kayapó land, and the film director James Cameron, who had visited the site before the auction, released a film against the dam, Message From Pandora, that November.
Juruna and Arara on the Volta Grande
The redesign that followed shrank the reservoir. Between 1989 and 2002 the main dam was moved upstream, cutting the planned reservoir from 1,225 km² to about 440 km², mainly to avoid flooding the Bacajá Indigenous Area. The 2008 impact assessment, prepared by Eletrobras with Odebrecht, Camargo Corrêa and Andrade Gutierrez, settled on a single run-of-the-river scheme. The Brazilian Constitution does not allow Indigenous land to be flooded, so the water is sent around it instead. The Pimental Dam, 36 m high and 6,248 m long, blocks the Xingu and forms the 333 km² Calha do Xingu reservoir. Canals about 12 km long then carry water to the 108 km² Dos Canais reservoir, held in by the 90-metre main Belo Monte dam and 28 dykes. The main powerhouse at the far end gets about 89 m of head.
The trade-off falls on the Volta Grande, the roughly 100 km loop of rapids between the two dams, where river flow drops by up to 80%. The Juruna and Arara peoples live here, along with sixteen other ethnic groups. Their land was not flooded, so they were not counted for resettlement, but they lost fisheries, river transport and clean water, and stagnant pools now breed waterborne disease. Critics noted that the environmental assessment did not deal with these problems. Norte Energia never obtained the free, prior and informed consent of the Juruna and Arara. In January 2011 FUNAI staff warned IBAMA about the impact on the Juruna land at Paquiçamba, but FUNAI's leadership said a few days later that it did not oppose a limited licence.
The fight then moved to the courts. Federal prosecutors had filed eleven lawsuits by February 2011. On 14 August 2012 Judge Souza Prudente stopped work because Indigenous peoples had not been consulted, and the Supreme Federal Court reversed him on 28 August. The UN Human Rights Council criticised Brazil's handling of the project, and the International Labour Organization said the state was breaking Convention 169 on Indigenous and Tribal Peoples, which Brazil has ratified, but there is no international mechanism to enforce either finding. Across the Xingu basin, more than 25,000 people from 18 ethnic groups depend on the river's seasonal floods and fish runs.
Altamira and Vitória do Xingu: 20,000 Displaced, 100,000 Arrivals
The people moved by the reservoirs mostly lived in the towns rather than the forest. The dam displaced more than 20,000 people, mainly from Altamira and Vitória do Xingu, and the government named resettlement programmes as necessary mitigation. Altamira is the largest municipality in Brazil, covering 159,534 km². It had 99,075 inhabitants at the 2010 census and 126,279 at the 2022 census. The project was expected to draw about 100,000 migrants, and Indigenous groups reported harassment, property destruction and deaths linked to construction and illegal logging.
IBAMA tied its approval to 40 social and environmental conditions. An October 2010 IBAMA report found that at least 23 had not been met, yet a partial installation licence followed on 26 January 2011 and the full licence on 1 June 2011. To get it, Norte Energia agreed to spend US$1.9 billion on social and environmental problems, and the company later promised R$3.7 billion for regional development. Two senior IBAMA officials resigned in 2009, citing political pressure, and the agency's president Abelardo Azevedo resigned in January 2011.
Zebra Plecos and the Xingu's 600 Fish Species
The Xingu is one of the Amazon's largest clearwater rivers. It runs 1,640 km and carries about 5% of the basin's water. Scientists estimate it holds around 600 fish species, and at least 26 of the species living in the lower river's rapids are found nowhere else. For some, the dried or drowned stretch is their entire known world range. Examples include the zebra pleco (Hypancistrus zebra), the sunshine pleco, the killifish Anablepsoides xinguensis and the Xingu dart-poison frog. An independent expert review concluded that the planned flow through the Volta Grande would not sustain this diversity and risked the extinction of hundreds of species. In 2016, once the dam was running, biologists and local fishers recorded species disappearing or moving, along with smaller catches and higher fuel costs.
Flooding also has a carbon cost. The project was projected to flood about 668 km² in all, about 400 km² of it forest, roughly 0.01% of the Amazon. Drowned vegetation rots and gives off methane. The National Institute of Amazonian Research (INPA) estimated that the full Belo Monte–Babaquara complex would emit 11.2 million tonnes of CO₂ equivalent in its first ten years.
Who Gets the 11,233 MW
The main powerhouse holds 18 Francis turbines rated at 611 MW each, and Pimental adds six bulb units of 38.85 MW. Run-of-the-river means almost no storage, so output follows the Xingu's seasons. Walter Coronado Antunes, a former São Paulo state environment secretary, estimated that the plant would produce about 1,123 MW between July and October and average 4,419 MW over the year, a capacity factor of 39%. The head of Brazil's Energy Research Company (EPE) called that "just a little below" the national average of 55%. Supporters reply that the Xingu runs low while other Brazilian hydro plants are full. An Eletrobras study found that even at reduced output Belo Monte could supply the whole state of Pará.
Critics say the plant only makes financial sense with storage dams upstream, especially Babaquara (renamed Altamira), which would flood another 6,140 km². Brazil's National Council for Energy Policy reportedly approved a resolution that only one dam would be built on the Xingu. Outside researchers have argued that much of Belo Monte's power will go to aluminium smelters rather than local homes. In 2007 WWF-Brazil calculated that efficiency investments could cut expected demand by 40% by 2020, saving power equal to 14 Belo Montes. A 2011 study by the Federal University of Rio de Janeiro disagreed, finding the dam cheaper than the alternatives in both money and social and environmental costs.
October 2019: A Low-Water Scare at the Main Dam
In October 2019, shortly before the last turbine went in, Norte Energia reported that low water had left part of the dam wall exposed to waves, and its chief executive asked for more water to raise the level from 95.2 m. To compare Belo Monte with the plants that outrank it, read our guides to Itaipu Dam on the Paraná and the Three Gorges Dam on the Yangtze, or follow the Xingu's water downstream in our complete guide to the Amazon River.