Belo Monte Dam

Belo Monte was first proposed in the 1970s during Brazil's military government but was repeatedly delayed by legal challenges from indigenous groups, environmental activists, and prosecutors. After more than three decades of disputes, construction began in 2011 under President Dilma Rousseff. The first turbine came online in 2016 and the plant reached full operation in 2019. The project sits on the Xingu River, a major tributary of the Amazon, near the city of Altamira in Pará state.

At 11,233 MW, Belo Monte is the fifth-largest power plant in the world and the second-largest in Brazil after Itaipu. It produces electricity for roughly 20 million Brazilian households and was designed to help Brazil meet rapidly growing electricity demand without expanding fossil fuel generation. Its capacity factor is low for a major hydroelectric project—the Xingu has a strongly seasonal flow, and Belo Monte was deliberately built without a large reservoir to limit its environmental footprint, leaving it underpowered for much of the dry season.

Belo Monte's reservoir is much smaller than typical for a plant of its size (about 500 km² versus over 1,000 for Itaipu), but the dam diverts a long stretch of the Xingu through a channel known as the Volta Grande, drastically reducing flow through a 100-km section of river that is home to several endemic fish species and traditional fishing communities. Researchers have documented severe declines in fish populations downstream of the dam since 2016. Indigenous communities, including the Juruna and Arara, have reported permanent disruption to their way of life.

Federal prosecutors filed dozens of lawsuits attempting to stop or modify the project, citing failures to consult affected indigenous communities as required by Brazilian law and ILO Convention 169. In 2022, Brazil's federal court ordered Norte Energia to compensate displaced communities and increase ecological flow through the Volta Grande. Construction-era corruption was central to the "Lava Jato" investigation that ensnared several major Brazilian construction firms.

• Belo Monte's main powerhouse, Pimental, sits on the natural course of the Xingu while a second powerhouse, Belo Monte, sits on the diversion channel. Most of the electricity comes from the diversion.
• The diversion canal moves more water than the Panama Canal handles in a day.
• During the rainy season, Belo Monte can briefly outproduce its 11.2 GW nameplate. During the dry season, it operates closer to 30–40% of capacity.
• Director James Cameron visited and publicly opposed the project in 2010, comparing it to scenes from his film Avatar.