Brazil’s Hydropower Industry Goes on High Alert as Severe El Niño Threatens Heavy Rainfall, Flooding and Energy Disruptions

Brazil’s largest hydropower companies are stepping up emergency preparations as meteorologists warn that a powerful El Niño weather pattern could bring intense rainfall to the country’s south in the coming months, raising fears of renewed flooding and disruption to one of the world’s largest hydroelectric systems.

Operators, including China Three Gorges (CTG) and Engie Brasil, say they have begun implementing contingency plans earlier than usual after scientists forecast what could become one of the strongest El Niño events in decades. Preparations include testing dam spillways, reinforcing flood protection measures, increasing weather monitoring and coordinating emergency response plans with communities living downstream of major dams.

The heightened alert comes as southern Brazil continues to recover from the devastating floods that struck Rio Grande do Sul in 2024. The disaster killed more than 180 people, displaced hundreds of thousands and caused widespread damage to homes, roads, bridges and critical infrastructure. Scientists later concluded that the flooding was intensified by a combination of climate change and El Niño-driven weather conditions.

Brazil relies on hydropower for roughly two-thirds of its electricity generation, making changing weather patterns a major concern for the country’s energy security. While abundant rainfall helps refill reservoirs and boost electricity production, excessive rain can force dam operators to release large volumes of water, increasing flood risks for nearby communities. Conversely, droughts linked to El Niño can reduce water levels in other parts of the country, particularly in the Amazon, limiting electricity generation and increasing dependence on more expensive and higher-emission thermal power plants.

Recent data from Brazil’s National Electric System Operator (ONS) shows rainfall across southern hydroelectric basins reached about 256% of the historical average during July, pushing reservoir levels close to 88% of capacity after falling to critically low levels earlier this year. Experts say the recent rainfall is not yet being driven by El Niño, but the weather phenomenon is expected to begin influencing southern Brazil within weeks.

Meteorologists warn that while southern Brazil is likely to experience above-average rainfall, northern parts of the country, including the Amazon region, could face below-average rainfall and worsening drought conditions. Such contrasting weather patterns are typical during strong El Niño events and could place additional pressure on Brazil’s electricity network, agriculture and water resources.

To reduce potential risks, hydropower companies say they have accelerated maintenance schedules, strengthened emergency response procedures and increased communication with civil defence agencies and residents living near reservoirs.