The Itaipu Dam, the world's most powerful dam, was built in Brazil in 1984. Recognized as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers in 1994, it stands as a monumental feat of engineering and a critical source of renewable energy.
Start of the Project:
The Itaipu Dam was constructed to generate 90,000 GWh of electricity annually. By 2000, it reached a generating capacity of 93.4 billion kWh, supplying 93% of Paraguay's energy and 20% of Brazil's. The project, costing £13.5 billion, was completed in seven years by 40,000 workers, with 149 fatalities during construction. Designed by Italian engineer Piero Sembenalli, the dam is 18 times larger than the Hoover Dam in the USA and nine times heavier, producing six times more electricity.
Construction and Design:
The river was diverted for the dam's construction, creating a 2km long and 80m deep channel—the largest diversion canal ever attempted. The reservoir, 100m deep and covering an area equivalent to Chicago, displaced approximately 10,000 families. Compensation required detailed surveys, including a door-to-door assessment for accuracy.
To achieve the required height of 400m for optimal electricity production, secondary dams were constructed across the valley. The dam, weighing 61 million tons, is a gravity dam designed to be so heavy that water pressure cannot move it. During construction, a weak layer of bedrock was discovered and replaced with 10 million pounds of extra-strength concrete.
Construction Challenges:
Engineers faced significant challenges, including managing the heat of hydration during concrete pouring, which was mitigated by using ice-cooled aggregate. The construction also required large-scale refrigeration plants, equivalent to 50,000 domestic freezers, to ensure maximum concrete strength. The reservoir was filled in 14 days by redirecting the river, and spillways were built to handle overflow, creating a man-made waterfall 22 times larger than Niagara Falls.
Project Details:
The dam spans 7,235m with a crest elevation of 225m and combines various dam types—earthfill, rockfill, concrete main dam, and concrete wing dam. Its spillways can handle 62.2 thousand cubic meters of water per second, 40 times the Iguaçu Falls' average flow. If Brazil used thermal power generation instead of Itaipu, it would require burning 434,000 barrels of oil daily.
Environmental Impact:
The Itaipu Dam's construction displaced 40,000 people and affected 129 bird species, 32 mammal species, and nine reptile species. Despite its environmental impact, the dam's construction speed was remarkable, capable of building a 20-story building in 55 minutes, using 140 tons of concrete every 20 minutes. The dam's excavation volume is 8.5 times greater than the Channel Tunnel, and its concrete volume is 15 times greater.
Completion:
Completed in May 1984, the Itaipu Dam's electric power cables could circle the globe 1.5 times. Managed by the Itaipu Binacional Company, the dam remains the world's largest generator of renewable energy, committed to mitigating environmental and biodiversity impacts.
Interesting Facts:
- The dam's construction required 40,000 workers and shifted 50 million tons of earth and rock.
- The concrete used could build 210 football stadiums the size of Estádio do Maracanã, and the iron and steel used could construct 380 Eiffel Towers.
Spanning 170 kilometers in length with a flooded area of 1,350 square kilometers, the Itaipu Dam, jointly owned by Brazil and Paraguay, meets 17% of Brazil's and 78% of Paraguay's energy needs.
Biodiversity and Conservation Efforts:
To maintain water quality and quantity, Itaipu has established an environmental conservation area, planting over 44 million trees. These protected zones now cover more than 100,000 hectares, including reserves and wildlife refuges in both countries and a biological forest corridor safeguarding the reservoir. Recently, Itaipu became the first hydroelectric plant globally to have its protected areas and landscapes recognized by UNESCO as a Biosphere Reserve.
In Paraguay, Itaipu coordinates the Paraguay Biodiversity program, supported by the Paraguayan government and the Global Environment Facility of the World Bank. This program aims to preserve biodiversity by connecting forest fragments and promoting sustainable land use.
In Brazil, protected areas are linked to the Santa Maria Biodiversity Corridor in the south and the Ilha Grande National Park in the north. Projects are also underway to conserve native animal species at risk of extinction in both countries.
Sustainable Development Initiatives:
Forest conservation is crucial for water security but must be complemented by other environmental priorities related to land use. Located in one of the most productive agricultural regions of Brazil and Paraguay, Itaipu faces environmental threats from agricultural activities, such as pesticide use, livestock waste, and soil erosion.
To address these issues, Itaipu has implemented various measures, including:
- Terracing agricultural areas to manage rainfall drainage and increase soil water retention.
- Promoting direct or no-till planting to reduce pesticide use and maintain soil moisture.
- Utilizing livestock waste to produce biogas for thermal, electrical, vehicular energy, and bio-fertilizer.
Additionally, Itaipu raises environmental awareness through education programs, encourages organic farming, supports crop-pasture-forest integrated systems, offers free technical assistance, repairs rural roads, and protects springs.
Economic and Environmental Impact:
Besides ensuring energy and water supply, the Itaipu Reservoir supports leisure, tourism, fisheries, and agriculture. Itaipu's initiatives align with the need to enhance dam efficiency and sustainably manage other local businesses.
For example, Itaipu has developed a production management system that schedules plant shutdowns for maintenance based on reservoir water flow, ensuring maximum energy production efficiency.
Performance and Record Achievements:
Through these enhanced management measures, Itaipu set a new record in annual power generation, producing 103.1 million MWh last year. To match this energy output, a thermal power source would need to burn 583,000 barrels of oil daily.
Conclusion:
The Itaipu Dam is a testament to engineering excellence and innovation, providing significant renewable energy while facing immense construction challenges and environmental considerations. Its legacy continues to impact energy production and infrastructure development globally.