Hydroelectric power station


San Juan

Located on the San Juan River 35 km west of the city of the same name, this is a diversion project for a gravel-faced dam with a concrete flood spillway and an open-air channel.  Generation is pressure-driven and there is an external power plant. With an installed capacity of 61 MW, the project’s energy production of 296 GWh is channeled to the National Grid System.

Punta Negra is complementary to the Caracoles Hydroelectric power system

More energy for San Juan and the country

63 MW

installed capacity

12.813.405 m3


15.000 ha

Irrigation availability

240.741 m3



Punta Negra Hydroelectric power station


EPSE (Energía Provincial Sociedad del Estado)


The dam is made of loose material with a waterproof concrete face, and rises 105 meters above the river bed. The crown is 750 meters in length. The dam holds a reservoir of 500 hm3 with a lake of 13 km length covering 1,250 hectares.

Flood flows will be referred to the spillway located on the left bank of the river that ends in a rectangular discharge channel of 160 m in length which allows for a maximum flow of 3,200 m3/s.

The Diversion Gallery consists of a double reinforced concrete pipe located on the right bank, a trunk section of 5.50 m x 7.50 m high and a second one of 3.00 x 3.00 m which is 472 m long. It is designed for a maximum flow of 500 m3/sec. and has an inflow regulator, a sluice chamber (which is transformed into the sluice chamber bottom outlet) and the outflow.

Hydropower conduction is composed of an intake with grilles, a floodgate chamber, a headrace tunnel which is 164 m long and whose circular section is 5.50 m in diameter, penstock of 115 m length which is variously 4.60 m and 3.00 m in diameter.

The hydroelectric plant is open-air and is equipped with two Francis turbines with an installed capacity of 30.83 MW. The same high voltage 132 kV line beginning in Caracoles distributes the energy generated to the Punta de Rieles substation in the city of San Juan.

The project employed over 1,300 professionals, technicians and local workers.