Cluster 1 · What it is
Itaipu Dam — the key facts
Complete specification
Location: Paraná River, Foz do Iguaçu, Brazil / Ciudad del Este, Paraguay
GPS: 25.4095°S 54.5939°W
Owner/operator: Itaipu Binacional — equal shares Brazil (ELETROBRAS) and Paraguay (ANDE)
Installed capacity: 14,000 MW (20 × 700 MW Francis turbines)
Type: Gravity dam — 196 metres high, 7,919 metres long
Reservoir: 1,350 km² · 29 km³ storage · 170 km length
Construction: 1975–1991
Cost: approximately $20 billion USD (final with financing costs)
Annual generation: 75–103 TWh/year (record 103 TWh in 2016; 96 TWh in 2023)
Historical total: over 2.7 billion MWh since commissioning — world record for any single generating facility
Frequency: A unique feature: Brazil uses 60 Hz, Paraguay uses 50 Hz. Itaipu has 18 units at 60 Hz (for Brazil) and 2 units at 50 Hz (for Paraguay), connected via frequency converter stations at each end.
Source: Itaipu Binacional · GEM Hydro Tracker CC BY 4.0
GPS: 25.4095°S 54.5939°W
Owner/operator: Itaipu Binacional — equal shares Brazil (ELETROBRAS) and Paraguay (ANDE)
Installed capacity: 14,000 MW (20 × 700 MW Francis turbines)
Type: Gravity dam — 196 metres high, 7,919 metres long
Reservoir: 1,350 km² · 29 km³ storage · 170 km length
Construction: 1975–1991
Cost: approximately $20 billion USD (final with financing costs)
Annual generation: 75–103 TWh/year (record 103 TWh in 2016; 96 TWh in 2023)
Historical total: over 2.7 billion MWh since commissioning — world record for any single generating facility
Frequency: A unique feature: Brazil uses 60 Hz, Paraguay uses 50 Hz. Itaipu has 18 units at 60 Hz (for Brazil) and 2 units at 50 Hz (for Paraguay), connected via frequency converter stations at each end.
Source: Itaipu Binacional · GEM Hydro Tracker CC BY 4.0
Two nations, one dam
The diplomatic and energy story
The Itaipu Treaty (1973)
The Treaty of Itaipu (26 ) between Brazil and Paraguay established Itaipu Binacional, a joint company to build and operate the dam. Each country: (1) owns 50% of Itaipu Binacional; (2) takes 50% of the electricity produced; (3) must sell any surplus electricity it cannot use to the other country at a fixed price. Paraguay, with a population of ~7 million, cannot use anywhere near 50% of 14,000 MW. Paraguay sells its surplus to Brazil at a price fixed by treaty — historically much below market price, a source of ongoing diplomatic tension. The treaty governs the relationship until 2023, when it expired and was renegotiated. Source: Itaipu Binacional official history
Paraguay runs on Itaipu
Itaipu supplies approximately 88% of Paraguay's electricity — making Paraguay one of the world's most electrically self-sufficient countries from a single renewable source. Paraguay's total electricity consumption is approximately 12 TWh/year — Itaipu generates 75–103 TWh. Paraguay sells approximately 50–60 TWh to Brazil annually under the treaty, generating significant revenue (approximately $450 million/year at treaty prices). Paraguay has the lowest electricity tariffs in Latin America, subsidised by Itaipu revenue. Source: ANDE Paraguay · Itaipu Binacional Annual Report 2023
What was lost
The Guaíra Falls — flooded in 1982
The Seven Falls — once the world's highest-volume waterfall
Before the Itaipu reservoir filled in 1982, the Guaíra Falls (Saltos del Guairá / Sete Quedas — Seven Falls) at GPS 24.06°S 54.26°W were the world's highest-volume waterfall by flow rate — approximately 13,000 m³/s average flow, nearly twice that of Iguazú Falls. They were a major international tourist attraction. When the Itaipu reservoir filled, the falls were completely submerged and permanently disappeared. This is one of the most significant deliberate destructions of a natural wonder in human history. The engineering decision to maximise reservoir storage sacrificed the falls. Brazil dynamited the remaining exposed rocks in 1982 to prevent them becoming a navigational hazard. Source: National Geographic historical records · Itaipu Binacional Environmental Report.
Questions
Which is bigger — Itaipu or Three Gorges?
Depends on the metric. Three Gorges is bigger by installed capacity (22,500 MW vs 14,000 MW) and is designated the world's largest power station. Itaipu generates more electricity per average year than Three Gorges in most years because the Paraná River (Itaipu) has a more consistent flow than the Yangtze (Three Gorges), which varies significantly with monsoon. However, Three Gorges' record annual output (103.1 TWh in 2020) exceeded Itaipu's record (103 TWh in 2016). Over their combined lifetimes, Itaipu has generated more cumulative electricity — more than 2.7 billion MWh — than any other power station on Earth. Itaipu is often described as the "world's largest generator of clean energy" on a cumulative basis. Source: Itaipu Binacional · China Three Gorges Corporation.
Source: Itaipu Binacional Annual Report · China Three Gorges Corporation
How does Itaipu compare to India's largest dams?
Itaipu (14,000 MW) dwarfs India's largest hydropower stations. Tehri Dam (Uttarakhand, 30.38°N 78.48°E) — India's largest at 1,000 MW. Koyna Dam (Maharashtra) — 960 MW. Nathpa Jhakri (Himachal Pradesh) — 1,500 MW. India's total hydropower capacity is approximately 47 GW — about 3.4 times Itaipu's single-site capacity. The reason is geography: the Paraná River carries approximately 14,000 m³/s average flow with a substantial head — a combination India's Himalayan rivers (high head but variable flow) and peninsular rivers (low head) cannot match in a single location. India's largest single planned hydro project is the 2,880 MW Dibang (Arunachal Pradesh) — still under development. Source: Central Electricity Authority India · NHPC India · Itaipu Binacional.
Source: CEA India 2024 · NHPC India · Itaipu Binacional Annual Report
What is Paraguay's energy situation because of Itaipu?
Paraguay has one of the world's most unusual energy situations. Itaipu supplies approximately 88% of Paraguay's electricity — making it almost entirely dependent on a single energy source and a single dam. This makes Paraguay's electricity among the cheapest and cleanest in South America. Paraguay exports approximately 50–60 TWh/year to Brazil, earning approximately $450 million/year — a major source of government revenue. The downside: Paraguay is completely dependent on Brazilian cooperation (since they co-own Itaipu). Any dispute over the treaty, or any long drought reducing Paraná River flow, creates an electricity crisis. Paraguay has no nuclear, coal, or significant natural gas — Itaipu plus smaller hydro plants represent virtually its entire electricity generation. Source: ANDE (Paraguay) · Itaipu Binacional Annual Report 2023.
Source: ANDE Paraguay · Itaipu Binacional Annual Report 2023
What was the environmental cost of building Itaipu?
Itaipu's 1,350 km² reservoir flooded a significant portion of subtropical Atlantic forest — one of the world's most biodiverse ecosystems, of which only approximately 12% remains. The Guaíra Falls (Seven Falls), once the world's highest-volume waterfall by flow rate (~13,000 m³/s), were completely submerged when the reservoir filled in 1982 and permanently lost. Approximately 10,000 indigenous people (primarily Guaraní Avá communities) were displaced — many receiving inadequate compensation. The construction displaced a total of approximately 40,000 people across Brazil and Paraguay. The reservoir altered the river ecosystem — changing water temperatures, sediment transport, and fish migration patterns. The dorado (Salminus brasiliensis) and other migratory fish populations were severely affected. Source: World Bank environmental assessments · IUCN · Probe International.
Source: World Bank · IUCN Freshwater Biodiversity · Probe International Itaipu Studies
Is Itaipu's generation affected by climate change?
Yes — Itaipu's generation is directly tied to Paraná River flow, which is driven by rainfall over the Brazilian and Bolivian highlands. In 2021, southeastern Brazil experienced its worst drought in 91 years — the Paraná River fell to its lowest level since 1944. Itaipu's reservoir dropped significantly, reducing generation capacity and causing electricity shortages in Brazil and Paraguay. The IEA and Brazilian electricity authority (ANEEL) have flagged increasing hydro variability as a key energy security risk for Brazil's predominantly hydroelectric grid. Brazil has responded by expanding solar, wind, and gas backup capacity. The 2021 drought cost Brazil approximately $5 billion in additional fossil fuel generation costs. Source: ANEEL Brazil · IEA Brazil Energy Policy Review 2021.
Source: ANEEL Brazil · IEA Brazil Energy Policy 2021 · ONS Brazil hydrology data
Itaipu BinacionalAnnual reports · Generation data · Diplomatic historyitaipu.gov.br
GEM Hydro TrackerGPS, capacity · CC BY 4.0globalenergymonitor.org
IHAInternational Hydropower Associationhydropower.org