I recently visited Itaipu, the world’s second largest hydroelectric dam, and came away with mixed feelings about hydroelectric energy. On the border of Brazil and Paraguay, the Itaipu dam is considered by many to be one the world’s great engineering marvels. Constructed on the world’s seventh largest river, the Parana, the huge dam generates 90% of all Paraguay’s energy needs and 20% of Brazil’s: a massive amount of energy produced with no waste products or carbon emissions!

The Itaipu dam, photographed from the special tour group viewing platform

Huge amounts of free, clean energy definitely sounds like a good thing. However, it is important to realize that even hydroelectric dams have an environmental cost. The initial construction of the Itaipu dam was a massive undertaking that produced a significant amount of carbon emissions as millions of tons of earth and concrete were shifted. The creation of Itaipu’s reservoir, needed to ensure a steady flow of water through the dam throughout the year, permanently flooded 1350 square kilometers of pristine forests and completely wiped out Brazil’s Guaira Falls National Park (the Brazilian government decided to sacrifice it). The subsequent decay of submerged plant material released large amounts of methane, a greenhouse gas much stronger than carbon dioxide, into the atmosphere. Most disconcerting to me, however, was how the promotional film that was presented to me at the dam’s visitor center boasted that the gigantic reservoir had filled in just 14 days, much faster than expected. Although this seems to be a source of pride for the engineers who constructed the dam, it’s clear to me that the wildlife living in the area had no chance to escape the swiftly rising waters- an immense mass-drowning of wild animals must have taken place.

According to the original agreement, Brazil and Paraguay each have a stake of exactly 50% in the Itaipu project. The two countries share the terrain of the facility equally and each country operates 10 of the 20 giant power-generating turbines. Moreover, each country supplies an equal number of employees in an identical distribution of job functions. Equal amounts of power are delivered to each country, however the electricity for Paraguay is delivered at 50 Hertz and the electricity for Brazil at 60 Hertz. Here the funny part: because Paraguay receives far more electricity than that country can consume, a surplus of about 80% of Paraguay’s electricity is subsequently sold to Brazil. This means that this surplus Paraguayan electricity must be converted to 60 Hertz and transferred back across the facility to the Brazilian side. A significant amount of energy is lost during this power conversion process, which in my opinion could be saved if Paraguay would simply set the output of 8 of its 10 turbines to 60 Hertz. However, as I understand it, Paraguay accepts this waste of energy because it prefers to maintain absolute sovereignty over its share of the facility’s power generation. Still, despite this odd arrangement, nobody can dispute the benefits of large amounts of free, clean energy for both countries.

Itaipu is not the only ‘dam issue’ in Brazil. Despite ongoing protests by environmentalists and indigenous peoples, the Brazilian government, together with major Brazilian energy and construction companies, is pushing for the construction of a new dam on the Xingu river in the northern Brazilian state of Pará. The government claims that the Belo Monte dam, as it would be called, would provide a welcome new source of power for Brazil’s rapidly growing economy. Unfortunately the location is not ideal; during the dry season the dam is only projected to operate at about 30% of capacity. According to the NGO Survival International, the Belo Monte project not only threatens the lands of indigenous communities, but would also inevitably lead to the extinction of dozens of local species of wildlife. A fervent opponent of the Belo Monte project, the World Wildlife Fund (WWF) asserts that Brazil could save 40% of the energy it currently uses if the country adopted energy-efficiency measures common in many other countries- this energy saving would be equivalent to 14 Belo Monte dams at full operation! Still, the Brazilian government continues to assert that the dam is necessary for Brazil’s ongoing economic development.

I personally believe that hydroelectric power generation can be a much-needed source of clean energy. However, do the large amounts of clean energy produced justify the initial environmental costs incurred? In the case of Itaipu, I’m tempted to say yes, considering the huge ongoing benefits for the economies and peoples of Paraguay and Brazil. The Belo Monte project, on the other hand, seems to hold little regard for the environment and the needs of future generations. I wonder whether the proponents of its construction have made an honest effort to weigh the costs of permanent environmental damage against the benefits of the large, but still limited, amount of free energy Belo Monte would produce.