Yacyretá Dam

View of the dam from down-river
Location of in Paraguay
Country	Argentina/Paraguay
Coordinates	27°28′57.68″S 56°43′29.95″W / 27.4826889°S 56.7249861°W / -27.4826889; -56.7249861Coordinates: 27°28′57.68″S 56°43′29.95″W / 27.4826889°S 56.7249861°W / -27.4826889; -56.7249861
Status	In use
Construction began	1983
Opening date	1994
Construction cost	$15 billion
Dam and spillways
Spillway type	Service, gate-controlled
Spillway capacity	55,000 m3/s (1,900,000 cu ft/s)
Power station
Commission date	1994–1998, 2011
Hydraulic head	22 m (72 ft)
Turbines	20 × 155 MW (208,000 hp) Kaplan turbines
Installed capacity	3,100 MW (4,200,000 hp) (final design)
Annual generation	20.091 TWh (72.33 PJ)

The Yacyretá Dam or Hydroelectric Power Station Jasyretâ-Apipé (from Guaraní jasy retã, "land of the moon") is a dam and hydroelectric power plant built over the waterfalls of Jasyretâ-Apipé in the Paraná River, between the Argentine Province of Corrientes and the Paraguayan City of Ayolas. The dam is named for Yacyretá Island just upstream, much of which the dam submerged. The word "Yacyreta" is the Hispanicized spelling of the original Guaraní term Jasyretâ.

The dam is 808 metres (2,651 ft) long, and its installed equipment has a maximum power output of 3,100 megawatts (4,200,000 hp), with a record maximum annual power output of 20.091 TWh (72.33 PJ) achieved in year 2012, and a maximum water flow rate of 55,000 cubic meters per second. Until February 2011, its reservoir was seven meters below its planned water level, only allowing it to operate at 60% capacity.

The project generated controversy and criticism during its planning and construction because of the effects it had on local ecology, particularly the flooding of a unique environment causing the extinction of several species. The financial management of the project also garnered criticism, as it greatly exceeded its original budget, ultimately costing more than $11 billion.

In 2014 Paraguay consumed almost 5 percent of its share of Yacyreta’s production, exporting the rest to Argentina.

Yacyreta is located 260 kilometres (160 mi) southeast of Asunción. It is located in the region of a city called Ayolas, 100 kilometres (62 mi) downstream from Encarnación and 2 kilometres (1.2 mi) away from the rapids of Apipé. The main dam is near the islands Jasyretâ and Talavera.

The initial protocol to determine the use of the waterfalls was signed on February 1, 1925 in the United States. However, it was not until January 1958 that the Technical Argentine-Paraguayan Commission was created to undertake technical studies of uses of the river. The studies were presented on December 3, 1973 in Asunción and the Treaty of Yasyreta was signed; both countries compromised to embark together in the construction. For that the Bi-National Organization Yasyreta was founded. Each state would share jurisdiction and responsibility for executing studies and projects related to the dam.