Brazil had 90.7 gigawatts of installed generating capacity in 2005, with the single largest share being hydroelectricity. In 2005, the country generated 396.4 billion kilowatthours (Bkwh) of electric power, while consuming 368.5 Bkwh. The largest source of electricity generation is hydropower (84 percent), with smaller amounts from conventional thermal, nuclear, and other renewable sources.

Brazil generated 334.1 Bkwh of hydroelectric power in 2005, accounting for 84 percent of its total electricity generation. Together with Paraguay, Brazil maintains the world's largest operational hydroelectric generating complex, the Itaipu facility on the Parana River, which generated 87.97 Bkwh of electricity in 2005. Many of Brazil's hydropower generating facilities are located far away from the main demand centers, resulting in high transmission and distribution losses. Brazil’s heavy reliance on hydroelectricity has caused some issues in the past, especially during years of below-average rainfall. In 2008, the government announced plans to build two new hydroelectric plants along Brazil’s borders with Argentina and Bolivia, representing 12,000 MW of new generation capacity. In addition, Suez Energy won a tender to build a 3,300-MW hydro station near Brasilia.

Conventional thermal generating sources provided only a small part of Brazil’s electricity supply. According to Brazil’s Ministry of Energy and Mines, about 4 percent of Brazil’s electricity generation in 2006 came from power plants fired by natural gas. Roughly a similar amount came from other thermal sources like coal, diesel, and fuel oil. Petrobras estimates that natural-gas fired generating capacity in Brazil could increase to 13,000 MW by 2017. Natural gas offers an alternative to the variability of hydropower but is largely dependent upon the availability of domestic and imported sources of the fuel. Brazil also has about 1,300 MW of installed coal generation capacity.

Brazil has two nuclear power plants, the 630-megawatt (MW) Angra-1 and the 1,350-MW Angra-2. State-owned Eletronuclear, a subsidiary of Electrobras, operates both plants. A third, 1,350-MW plant, Angra-3, remains partially constructed. In 2007, Electronuclear received permission from the Brazilian government to resume construction of Angra-3, and the company also began the process of applying for permission from Ibama (Brazil’s environmental regulatory agency) to begin operations at the plant. Construction on Angra-3 began again in 2008. Electronuclear announced in August 2007 that it had begun the process of selecting a site for a fourth nuclear power plant in Brazil. According to the government, both of these new plants will use fuel produced in Brazil, rather than imported from Europe.

In recent years, Brazil has run an overall power surplus, allowing exports to its neighbors. In 2007, Brazil began exporting electricity to Uruguay. In 2008, it exported power to Argentina during the winter in exchange for receiving electricity back from Argentina during the summer.