|Fig. 1: The Itaipu Dam (Source:Wikimedia Commons)|
The Itaipu dam is known as one of the seven wonders of the modern world due to its sheer immensity. It spans the Parana River separating Paraguay and Brazil; each country owns half of the 14,000-megawatt output that the dam produces.  To complete this project, approximately 50 million tons of earth were removed during construction, and 18 hydroelectric generators each spanning 53 feet were placed into the dam (2 more were added in an expansion in 2006 to bring the total to 20). As a result of their massive size, each generator is capable of handling 160 tons of water per second.  Also, given the agreement of an equal split of the output energy between the two countries, Paraguay has been able to sell the excess electricity that they possess to Brazil and to other countries around the world. The idea for the Itaipu dam began to take shape when the Ministers of Foreign Affairs of Brazil and Paraguay signed the Act of Iguacu in 1966. This Act resulted in the exploration of the Parana River as a potential energy source.  In 1975, construction began on the dam; the 4.8 mile-long structure was completed in 1991, with an expansion completed in 2003 that resulted in an additional 1,400 megawatts of energy produced.  It is a concrete gravity dam that has used enough iron and steel in its construction to build 380 Eiffel Towers and 15 Channel Tunnels between England and France.  The reservoir feeding into the dam is 170 km in length and can hold approximately 29.54 billion tons of water.  Given its magnitude, it is able to supply a huge amount of power and bring positive international attention to these two countries. However, there were some large consequences, both positive and negative of building this dam. While its completion provided a large new energy source for both countries, many families were displaced from their homes to accommodate the new man-made structure shifting the course of the seventh biggest river in the world, and an entire waterfall was lost in the process. 
There were both positive and negative effects on the local surroundings and communities as a result of the building of the Itaipu dam. Initially, the project brought a boost to the economy of Paraguay and allowed the development of an electricity market from which Paraguay and Brazil have both benefitted to varying degrees.  However, the electricity generated initially did not help Paraguay's economy greatly, as the upper class prevented the move towards industrialization. Thus, the focus stayed on farming; as the dam was being completed, Paraguay's main crops plummeted in value worldwide, causing economic havoc.  During the push towards democratization, the market somewhat recovered and this electricity was put into use to help develop industry in the country. However, there was also much controversy about Paraguay's selling of excess energy back to Brazil on the part of the Paraguayan people, worrying about the corruption of their government, but their voices were drowned out in their government's signing of the Itaipu Treaty of 1973.  Another negative impact of dam construction was on the surrounding natural wildlife. Though natural protection projects were put into place throughout construction of the dam, large amounts of forest along the Paraguayan side of the river had been destroyed.  Also, multiple waterfalls and dips have been overrun by the development of the reservoir, destroying some of the natural beauty of the region. However, much work has been done to save much of the wildlife and vegetation that had the potential to be destroyed by the creation of the dam, as programs put in place were able to save about 400 total species. . One must also note that 59,000 people were displaced from their homes and forced to relocate as a result of the construction of the dam.  This is a very large number, and a decision not to be made lightly. However, it was deemed appropriate by the directors of the project, as the net output of energy and benefit to Paraguay outweighed the inconvenience of this relocation.
In 2006, the Itaipu dam expanded its capacity, generating 14,000 MW of electricity for use by both Paraguay and Brazil.  As a basis for comparison, the Hoover Dam initially generated approximately 1,951 MW when it is running at full capacity, and the Three Gorges Dam in China has 26 power-generating units that together provide approximately 22,500 MW of electricity. [5,6] The Three Gorges Dam is the most recently built dam of the three, and provides energy to a rapidly expanding country that is consuming it in large proportions. Paraguay and Brazil have been able to benefit the most from the large energy output provided by the Itaipu dam, with Paraguay exporting most of this generated energy due to its lack of consumption, and Brazil benefiting by having first rights to buy the excess energy that Paraguay sells at a highly discounted price. 
Both Paraguay and Brazil have gained much in the development and operation of the Itaipu dam. However, this benefit did not come without cost, as the displacement of such a large amount of people and the destruction of a natural monument are decisions not to be taken lightly. This source of hydroelectric energy has helped to reduce dependence on coal and oil in both countries and has also resulted in a more connected relationship between the two countries through their joint partnership. Though there were some heavy costs incurred, the Itaipu dam emerged as an environmental, fiscal and political success; the ability to generate such a large amount of hydroelectric energy has saved each country financially and has also been a small step in reducing the world's oil dependence.
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