The two large dams under construction on the Madeira River, Jirau and San Antonio, which together will provide nearly 7,000 MW of electricity, continue Brazil's reliance on hydropower. Mega-dams—such as the 14,000-MW Itaipu, which began during the 1970s under the military dictatorship—have helped move Brazil to No. 2 behind China on the world's hydro list. Dams generate between 80% and 90% of the country's electricity.

The strategy seems likely to continue under President Dilma Rousseff. On her way to the top, Dilma served as the Rio Grande do Sul state energy secretary before becoming federal energy secretary under her predecessor and political mentor, Luiz Inácio Lula da Silva. Together, Dilma and Lula began to formulate an ambitious power program that calls for construction of 20 dams in the Amazon basin by 2020.

Even though hydropower has helped Brazil's economic expansion, lessening its dependence on imported oil and strengthening the electrical gird's reliability, the program has plenty of critics.

"We're not anti-dam as a fundamental principal," says Brent Millikan, Brasília-based director of the Amazon program for the non-governmental organization International Rivers, Berkeley, Calif. "But we do think it should be done responsibly, with awareness of the effects large dams have on the environment and also on the indigenous people in the Amazon basin who depend on floodplain agriculture and the fisheries." Government often rams through dam license approvals, he claims.

Dissenters are fired from government jobs, Millikan asserts. Even when international lenders are reluctant to take on financial risks, Brazilian banks backed with public funds step into the breach, he says.


On Aug. 14, a federal judge in São Paulo halted construction at the site, pending further consultation with indigenous people. An appeal is expected.

The Jirau and San Antonio dams—each is approximately a third the size of Belo Monte and still huge by global measures—raised many of the same issues prior to licensing in 2007 and 2008.

Managers with Odebrecht and Camargo Corrêa, the respective consortium leaders at San Antonio and Jirau, stress how different their dams are from Itaipu and other huge predecessors, with fish-friendly, run-of-river turbine design, a reduced reservoir footprint, extensive training and relocation programs benefiting local people.

Millikan remains unconvinced. He says the country's policymakers ignore inconvenient scientific studies, brook no dissent, override injunctive relief with prolonged delays and guarantee windfall profits for contractors while effectively transferring financial risks to Brazilian taxpayers.

Once the Madeira dams secured licenses, each project became a large-dam construction challenge involving river diversion, extensive foundation work and powerhouse construction on each bank. The civil works at San Antonio required excavation of 27,000 cu meters of earth, more than 22,000 cu m of rock and placement of more than 3 million cu m of concrete, says Leonardo Borgatti, director of civil works. The site makes use of a midriver island, which was incorporated into the structural design.

At a remote site more than 140 kilometers upriver, the Jirau dam is similar in scale but slightly different in configuration. The Consorcio Energia Sustentável do Brasil consortium won the project bid by offering an alternative site that cut excavation work by about half.

The earthen dam has an asphalt-core design, the second instance in which this feature has been employed in Brazil.

The San Antonio dam is now placing power on the grid; Jirau will follow suit the next year. Both are negotiating to add new turbines for more power.

The 11,233-MW Belo Monte Dam would be the world's third-largest hydro dam. It is planned for a remote stretch of the Xingu River in Para state and has drawn widespread protest in Brazil and beyond. In July, anti-dam natives seized three engineers working for Norte Energia, the dambuilding consortium led by state-run Electrobras, which holds a 49% stake. They released the hostages after Norte Energia reiterated its pledge to spend $1.6 billion on social programs.