An Engineering Marvel – The Itaipu Dam in Brazil

Sometimes, when countries come together to create something bigger, for a larger cause, architectural marvels are born. One such example is the Itaipu Dam that was built over the Paraná River between Brazil and Paraguay in South America that was built to serve many generations to come. Let’s take a closer look…

WORDS BY- AMOG

In the 1960’s, the governments of Brazil and Paraguay respectively saw a way of working together on a project that used one of their shared resources to support the expanding electrical needs of their countries. This resource was the Paraná River, the seventh largest in the world, which formed a natural border between the two nations. The project was a massive dam that would harness the river’s energy and turn it into electrical power.

Thus, on July 22, 1966, the Brazilian and Paraguayan Ministers of Foreign Affairs signed a document agreeing to explore the possibility of building a dam and an associated hydroelectric plant. It wasn’t until February 1971, however, that the work actually started. Once construction was underway, there were still legal considerations to be handled. In particular, the country of Argentina, only a few miles south of the dam site, was concerned that in times of conflict, the dam could be used as a weapon to cause large-scale destruction. To quell these concerns, the three nations entered into a mutual agreement in October of 1979 on the amount of water that could be released at any time from the dam.

Today, the Itaipu Hydroelectric Dam is the largest operational hydroelectric energy producer in the world, with an installed generation capacity of 14 giga watts. The plant is operated by Itaipu Binacional and located on the border between Brazil and Paraguay. Energy generated by Itaipu helps meet demands of the two countries. About 90% of the energy generated by the plant is used by Brazil.

Construction of the dam began in February 1971 and cost a magnanimous sum of $19.6 bn. The first unit began generating power in May 1984. Later that year, the second generating unit started operating. And till 2009, Itaipu had 20 generating units, each with a capacity of 700MW.

Itaipu generated 94.68 billion kWh of energy back in 2008, sufficient to meet worldwide power consumption for two days. It is equal to the energy consumed by Paraguay for 11 years and by Argentina for one year. This energy was used to supply 87% of the electricity consumed in Paraguay and 19% as demanded by the Brazilian interconnected system.

But building this powerhouse of a dam was no easy task. During the planning stages, the engineers had to decide what type of dam was needed and how big it should be. A simple dam placed at the chosen spot on the river would have blocked it, but only would have created a lake 150 feet deep, not enough to produce all the power that was wanted. Instead, it was decided to make Itaipu not just a single dam but a series of dams 7.2 km long and 738 feet high. This would permit the creation of an immense lake that would allow the Itaipu to produce more hydroelectricity than any other dam in the world.

The first job the construction crew had to do was to divert the flow of the river around the construction site so that it was dry enough to start building. As the Paraná is one of the largest rivers in the world, this project in itself was a challenge. Over 50 million tons of rock and earth were removed to create a bypass channel for water that was 490 feet wide, 300 feet deep and 1.3 miles long. In addition, temporary cofferdams were placed in the river’s old path to keep water out of the construction zone. This river diversion was the largest ever attempted and took three years to complete. On October 1978, the concrete blocks were blasted out of the way to open the new channel and let the water pour through.

The construction of the dam itself required 40,000 workers, mostly recruited from Brazil. To house them, a whole new community was built including hospitals, schools, parks and churches. Sadly, 149 of these employees were killed during the construction project.

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More than 12.3 million cubic meters of concrete were poured to create the dam. Some sections of concrete were so large that if allowed to set naturally in the hot sun they would not have dried properly, causing cracks and weak spots.

More than 12.3 million cubic meters of concrete were poured to create the dam. Some sections of concrete were so large that if allowed to set naturally in the hot sun they would not have dried properly, causing cracks and weak spots. To avoid this, large-scale refrigeration plants equivalent to almost 50,000 domestic deep freezers were used to cool the concrete while it hardened. In addition, enough iron and steel were used during the construction to build 380 copies of the Eiffel Tower. More than 8.5 times the rock and soil were moved in the building of the dam than was needed to cut the channel tunnel between England and France.

The construction also used 15 times more concrete than the “Chunnel.”

On October 13, 1982, the dam was completed to the point where the diversion channel could be closed and the lake filled. On May 5, 1984, the first of the power-generating units was completed and brought on-line to officially open the dam. The rest of the units were installed over the next seven years, slowly increasing the capacity of the dam each year.

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