The preponderant role of hydroelectric production is called into question. Most Amazonian power plants could face drastic reductions in their electrical energy production potential, with losses projected between 30 and 40% in the coming decades, due to the impacts of climate change.
The finding is part of a new study by ANA (National Agency for Water and Basic Sanitation) on climate projections of precipitation patterns, river flow and water security in Brazil in the coming decades. The projected reduction considers a horizon of four decades, until 2065.
If investments in new projects continue to be based solely on historical data, experts warn the country could experience a wave of plants unable to produce the expected energy, leading to increased costs for consumers and a reliance on fossil thermoelectric plants.
According to the report “Impact of climate change on Brazil’s water resources”, the drop in production would be a consequence of the changes that could occur in the natural flow regime of water due to global warming.
By observing the already verified behavior of average river flows in the period from 1950 to 2014, the document projects performance in the near future, until 2065, and for more distant periods, in a horizon up to 2100. The result shows that the Northern region is the one most likely to be affected.
While the South, Southeast and Center-West tend to see drops in hydroelectric production of up to 10%, the Amazon could experience greater losses due to reduced flows, affecting large plants already installed and projects planned for the coming years.
“Considering that energy production is directly related to the average flow of influence, the South, Southeast and Central-West regions show reductions of 0 (zero) to 10%, while the Northern region presents the most pessimistic projections, with changes of 30 to 40%,” the study said.
“Among existing projects, the largest impacts are concentrated on the plants with the highest installed capacity, most located in the Amazon basin,” the document continues.
The study by the National Water Agency highlights that, if nothing is adjusted, Brazilian hydroelectric expansion risks being planned based on a climate scenario that will no longer exist.
Over the past two decades, the country has invested in the Amazon, the last great maritime frontier, to develop its hydroelectric capacity, with the construction of power plants such as Belo Monte, on the Xingu River, and Santo Antônio and Jirau, on the Madeira River.
It turns out that, according to the document, these power plants were designed taking into account historical flow series which no longer represent the future course of the rivers. With the lengthening of dry seasons and the anticipation of loss of soil moisture, phenomena already observed each year in Xingu and the southern Amazon, the water cycle in the region is experiencing a phase of structural change.
On the Amazon River, floods and extreme droughts have increased in recent decades. Looking at the period of the last 125 years, we see that of the ten largest floods in the region, seven occurred in the last 16 years, starting in 2009.
In the case of droughts, among the 10 lowest levels observed, 5 occurred in the last 28 years. In 2023 and 2024, the region recorded two consecutive unprecedented droughts, with water levels much lower than those seen in the past.
ANA argues that integrating future climate scenarios into long-term planning is not just a technical recommendation, but a necessity to avoid financial losses and energy insecurity.
Brazil currently has 216 gigawatts of electrical energy, with more than 24,000 plants in commercial operation, according to Aneel (National Electric Energy Agency). Half of this production comes from river energy, 50.5% of which is linked to hydroelectric plants of all sizes.
The study reinforces that the effects are not limited to electricity production. The reduction in flows will also affect irrigation, urban supply and biodiversity, if the planning of these areas does not include climate projections.
The results indicate that climate changes in hydrology are expected to affect water security in much of Brazil, while other regions are expected to suffer from an increase in flash floods and urban flooding, as seen in Rio Grande do Sul in 2024.
On the public sector side, the lack of financial resources has compromised the resolution of the problem, says the ANA. “The political sustainability of water and climate policies remains threatened by budget cuts, institutional discontinuity and the absence of a state policy that sustainably unites water and climate,” the agency states in the document.
The ANA says a possible change in position “requires fiscal protection, greater social participation and regulatory innovation, to recognize uncertainty as a starting point for ensuring water security in increasingly unstable climate scenarios.”
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