Brazil awarded a domestic consortium on Tuesday rights to build the world’s third-largest hydroelectric dam in the Amazon rain forest in a chaotic auction amid criticism the dam is an environmentally hazardous money loser.

President Luiz Inacio Lula da Silva likely faces a prolonged battle over the 11,000 megawatt Belo Monte dam that he has heavily promoted despite opposition from a range of critics including Hollywood director James Cameron.

Government leaders say the project, due to start producing electricity in 2015, will provide crucial power for Brazil’s fast-growing economy, but environmentalists and activists say it will damage a sensitive ecosystem and displace around 20,000 local residents.