The Itaipu Dam, straddling the Paraná River between Paraguay and Brazil, is one of the world’s largest hydro‑electric complexes. Its massive infrastructure supplies the majority of Paraguay’s electricity and a substantial share of Brazil’s, while operating within a tightly controlled 10,000‑hectare priority zone.
Location and Access
- The dam sits in a 10,000‑hectare “priority area,” split evenly (5,000 ha each) between Paraguay and Brazil.
- Access is restricted to personnel employed by the binational entity that runs the plant; unauthorized entry is prohibited.
Core Facilities
- Substation (Paraguayan side): Receives generated power via 520 kV high‑tension lines.
- Spillway: Equipped with a single gate capable of releasing roughly 6 million L s⁻¹, it regulates excess water when the reservoir is full. The spillway is rarely opened because the dam’s storage capacity is large.
- Dam Structure: Comprises an earth‑fill embankment, a rock‑fill core, and a concrete spillway curvature that links the spillway to the main dam.
- Turbine Hall: Contains 20 turbine units—10 on each side of the river—housed within “white‑top” housings. The interior of the dam is hollow, forming a triangular cavity that reduces material use while maintaining structural strength.
Power Generation
- Installed capacity: Approximately 14 GW (7 GW per country).
- Contribution to national grids: Around 90 % of Paraguay’s electricity is supplied by Itaipu; Brazil receives a significant portion of the remaining output.
- Cooling system: Water discharged from the turbines circulates through the dam’s structure to keep the generating units from overheating.
Environmental Notes
- The Paraná River’s characteristic greenish hue is natural, caused by mineral deposits and rock formations on the riverbed.
- The spillway’s design minimizes frequent releases, helping to maintain stable water levels and reduce downstream ecological disruption.
Comparison with the Three Gorges Dam (China)
- Location: Near Yichang, China; built primarily for flood control rather than power generation.
- Size: Reservoir covers roughly 1,300 km² and can reach depths of up to 120 m.
- Dimensions (as described): Approximately 70 m tall with a base width of 300 m; extends about 2 km along the river.
- Installed capacity: Larger than Itaipu, making it the world’s highest‑capacity hydro‑electric facility.
- Energy output: The Three Gorges Dam tends to produce the greatest annual electricity generation among global dams, though Itaipu remains a leading producer in terms of consistent output for its region.
Both dams illustrate the scale of modern hydro‑electric engineering, yet they serve different primary purposes—Itaipu focuses on power supply for two nations, while the Three Gorges Dam emphasizes flood mitigation alongside energy production.
