Brazil gets 60 percent of its electricity from hydroelectric power plants. But much of the country, including in the Amazon rainforest area, has been enduring a severe drought. Water levels at many Brazilian dams have dropped to dangerously low levels.
The Balbina pilot project, to be completed by 2017, is a large platform with 50,000 square meters (540,000 square feet) of solar panels, about the size of five football fields.
The panels can produce five megawatts of electricity, enough to supply some 9,000 homes with power.
Engineers hope to increase the output to 300 megawatts, allowing Balbina to produce electricity for 540,000 homes.
"We're going to transform the hydroelectric power generators, that have limitations due to the weather, into unlimited power producers because they will also use solar energy," said Orestes Goncalves, president of Sunlution.
His company partnered with French firm Ciel et Terre to install the panels at Balbina.
The engineers have not said how much cheaper electricity could be for local residents, but one of the project's long term goals is to bring down utility prices.
Separately, engineers will measure the efficiency of this hybrid model with floating solar panels at two very different locations: at Balbina, where the rainforest weather is hot and humid, and at a dam in the hills of the semi-arid northeastern state of Bahia.
If successful, officials hope to expand the floating panel system via public tenders.