​Hydroelectric power, generated by water from rivers and lakes, accounts for more than 60% of the energy generated in Brazil, and is the main source in the country. Worldwide, it is the third most used form of energy, representing 16% of the energy generated globally, and is considered renewable and significantly cleaner than alternatives such as coal and natural gas, which occupy first and second place in the world ranking.

It is understood that it is a very important energy source, but how is it produced, what are its advantages and other interesting facts?

What is hydroelectric power and how does it work?

Hydroelectric power, also known as hydraulic energy, is obtained from the potential energy of a body of water and, in nature, comes from rivers and lakes.

It works through hydroelectric plants, through a system that captures water from rivers and conducts it through structures until it reaches the turbine, which has parts connected to the electric power generator. The force of the water pushes the turbine blades and the energy of this movement generates electricity. After use, the water is returned to the rivers with the same quality as before – which makes this type of energy generation considered renewable.

Why is hydroelectric power so important?

In addition to being renewable and clean, there are other advantages to using hydroelectric power. With the possibility of reusing water (often used for other purposes, such as irrigation), there are several positive points in using this energy source, such as the fact that it is cheap and allows for a long useful life for the projects used in its generation.

Since many plants have reservoirs, it is possible to plan well according to user demand. This is why hydroelectric power is more reliable than other renewable sources, such as wind power, which depends on the availability of winds. In addition, hydroelectric plants are beneficial to the country's and local economy, generating income through jobs and even tourism, and they are facilities that emit less carbon dioxide (CO2), thus also helping to preserve the environment.

Interesting facts about hydroelectric power

There are currently over 60,000 hydroelectric plants in the world. Three of the largest are located in Brazil: Itaipu, Belo Monte and Tucuruí. Another interesting fact is that some studies show that using hydroelectric power instead of fossil fuels (oil, natural gas and coal) to generate electricity has helped to prevent over 100 billion tons of carbon dioxide emissions over the last 50 years.

Hydroelectric projects can be used to regulate and store water to mitigate the impacts of extreme weather events, such as floods and droughts, which are increasing due to climate change.

How do hydroelectric plants work?

Hydroelectric plants are responsible for generating electricity by using water from rivers and lakes. The first in the world began operating on September 30, 1882, in the United States. In Brazil, the Marmelos Plant was opened in 1889, in Juiz de Fora, Minas Gerais. In addition to being the first in the country, it was also the first in South America.

There are currently more than 60,000 hydroelectric plants in operation around the world. The largest of them, the “Three Gorges Plant” (name translated into Portuguese), is in China. The second largest is Itaipu, in Foz do Iguaçu (between Brazil and Paraguay), powered by the waters of the Paraná River.

Dam safety

Dam safety is the condition that aims to maintain their structural and operational integrity and the preservation of life, health, property and the environment. Safety planning is so fundamental to the operation of hydroelectric plants that it takes into account technical aspects of the dam and the current safety situation, obtained through periodic inspections and analyses of instrumentation.

The dam safety routine established in the Dam Safety Plan (PSB) is what will prevent internal and external incidents and accidents that could pose a high risk to populations in regions close to the plants, in the worst and least likely scenario.

As an effective example, the Emergency Action Plan (PAE), a procedure belonging to the PSB, has the function of predicting possible anomalies in the dam, implementing effective actions to avoid its rupture and, if it is not possible to prevent it, issuing advance warnings and drawing up strategies together with the local civil protection and defense authority to avoid or minimize its consequences for the populations.

What is the main objective of the PAE?

This plan defines the processes for identifying, mitigating or treating pathologies, materials necessary for interventions and warning systems. Internal and external simulations are also carried out periodically, putting the plans into practice, evaluating their effectiveness and correcting deviations so as not to leave anything to improvisation in a possible emergency, no matter how small its probability.

How important is it to have a structured PAE?

Even if a dam presents adequate performance, if an anomaly is identified in the structure, an effective and early response to control the occurrence is the best way to act. In cases where the dam presents anomalies, such as the identification of a structural problem, for example, it is essential to carry out constant monitoring, as well as preventive interventions to avoid accidents. The PAE also indicates the use of various systems to warn the population in the safety protocol. When there is a risk situation that could compromise the structure of the dam, these systems are activated. Thus, when the warning is activated, it indicates that people must leave the potentially floodable area, go to the meeting points identified with signs in the field and wait for guidance from civil defense at these points.

What to do if the warning systems are activated?

• Stay calm
• Stay away from rivers and streams
• Seek safe places on higher ground
• Go to the meeting point established by the authorities 
• Follow the authorities' instructions
• Keep the telephone lines free
• Do not use elevators
• Do not return to your place of residence until permitted by the civil protection and defense authorities
• Do not run, as the travel time to the meeting point is calculated using normal walking

IMPORTANT: Dams are designed for extraordinary floods, with a probability of occurring once every 10,000 years and verified by the project for the maximum flood possible to occur in the river basin. These studies are updated at the time of the Periodic Review of Dam Safety (RPS) every 7 years, always keeping this information up to date.

Despite this, extraordinary floods are always monitored by the operation of the dams, however, natural floods can affect the inhabitants of the banks of streams and rivers with or without the presence of the dam in the region.

In order to contribute to the surrounding community and its protection, Neoenergia notifies the local civil protection and defense authorities legally responsible for flood management every time a flood occurs in the rivers where it operates. In addition, it has made available to civil protection and defense agents and the community in general the hydraulic data of operation in real time via the PROX App, available in the Android and iOS APP stores, which can be accessed by the QR codes below:

Hydroelectric power in Brazil

The presence of a dense drainage network that bathes the national territory (mainly in the south and southeast regions), which is composed of large, powerful rivers formed on plateau terrain, with slopes that favor waterfalls and the formation of currents. The reservoirs of hydroelectric plants can control the supply of energy, balancing supply and demand with a sustainable and renewable source of energy, essential for the development of other renewable and intermittent energy sources, these are essential factors for Brazil's investment in this energy source. With its commitment to renewable energy and following these opportunities, Neoenergia, one of the largest companies in the electricity sector, invests in five hydroelectric plants in the country: Itapebi, Corumbá, Dardanelos, Baixo Iguaçu and Belo Monte.

According to the National Electric System Operator (ONS), hydroelectric plants are located in 16 river basins in different regions of Brazil. These are areas close to Brazilian rivers with the largest capacity for hydroelectric power plants: Tocantins, São Francisco, Grande, Paraná, Iguaçu and Paranaíba.

Regarding energy generation potential, in 2021, the country reached the mark of second country with the largest installed capacity in the world, with 109.4 GW, behind only China, which has a capacity of 391 GW, according to the International Hydroelectric Association (IHA). Next in the ranking are: United States (101.9 GW), Canada (82.3 GW), Russia (55.7 GW) and India (51.4 GW). In total, the installed capacity worldwide is more than 1,300 GW.