It’s such a wreck. In the area that receives the large lake that serves as a reservoir for the hydroelectric plant, nature is transformed: the climate changes, species of fish disappear, animals flee to dry shelters, trees turn to rotten wood under the flood… And that aside, the social impact: thousands people leave their homes and have to start their lives from scratch elsewhere. In Brazil, 33,000 homeless people are in this situation, and they even created an organization, the Movimento dos Atingidos por Barragens (MAB). It may seem like a catastrophe, but compared to other types of energy generation, hydroelectric power is not bad at all. When we consider environmental risks, nuclear power plants are more dangerous. And if we think about the global climate, thermoelectric plants – which work by burning gas or coal – are the worst, as they release gases into the atmosphere that contribute to the greenhouse effect. The truth is that there is no way to generate 100% clean energy. “Every extraction of energy from nature has some impact. Even wind energy (which uses the power of the wind), which seems harmless, is problematic. Those who live under the huge propellers that generate energy suffer from noise, vibration and visual pollution, in addition to the system disturbing the migratory flow of birds, as happens in Spain», says engineer Gilberto Jannuzzi, from the State University of Campinas ( Unicamp). Another problem with alternative sources is the economic aspect: solar energy, for example, is much less impactful than hydroelectric power, but it costs ten times more and cannot feed the high expenditure of large cities. Because of this, environmentalists defend the banner of reducing consumption. According to environmental educator Sérgio Dialetachi, coordinator of Greenpeace’s energy campaign, it would be possible to save 40% of the energy produced in the country with three measures. First, by installing more efficient turbines in old power plants. Second, by modernizing transmission lines and combating energy theft. Third, returning to the behavior of the rationing period, in 2001, with less wasteful equipment and habits. All this would prevent the need for new hydroelectric plants to be built, protecting our planet a little more.
Lake of the mills changes the climate and all aquatic biodiversity
STEEP CLIMB
To ensure that migratory fish are able to go up the river to mate, one of the ways is to build aquatic “ladders”. Each group of steps has a rest area so that the fish does not have muscle cramps when climbing.
SUFFERING RIVER
The reservoir level of hydroelectric plants needs to be maintained at a constant level. For this, technicians open and close the floodgates depending on the rainfall. It is the river that receives water from the lake that loses out: the change in water volume disrupts all aquatic life — especially on the banks, which face periods of drought and flooding
CLIMATE CHAOS
What was once a forest suddenly turns into a lake. This change increases the amount of water that evaporates and, consequently, affects three other climatic factors: total rainfall, humidity and temperature, which suffers variations of up to 3ºC. With this mess, crops that survived the flood could be harmed.
IMPROVISED RESCUE
Part of the fauna that occupied the region of the lake is isolated with the flood. When the lake at the Itaipu dam was formed, for example, 30,000 animals were rescued and taken to reserve areas. Some died because they did not adapt to the new habitat. The rescue continues today: when the turbines stop for maintenance, the fish that enter the ducts are removed
STARTING OVER
In the flooding for the formation of the dam, many plant species are submerged, reducing biodiversity. To reduce the problem, hydroelectric builders have reforestation programs on their banks. The Itaipu plant, for example, received 20 million seedlings around its reservoir
CHANGED FISHERIES
The formation of a lake changes the habits of aquatic life, causing some species of fish to disappear and others to multiply. On the Paraná River, the most numerous types changed with the installation of Itaipu:
BEFORE ITAIPU
Black Pleco – 22%
Golden – 17%
Pacu – 13%
AFTER ITAIPU
Armed – 38%
Corvina – 15%
Mapará – 13%
DANGEROUS BUBBLES
Submerged in the lake for several years, trees and plants rot and release methane gas bubbles, a pollutant that corrodes turbines, prevents the reproduction of some fish and allows the proliferation of algae, causing water imbalance. Some methane bubbles are so big that they turn over a small aluminum boat!