The work and the technique: Yacyretá Hydroelectric Project, Colombia
Works to build the Yaciretá dam were awarded to the 35 companies of the Eriday U.T.E. Consortium led by the Italian Impregilo, later merged into the current Webuild Group.
Twelve thousand people were involved in building the Yaciretá dam. 4,375,000 cubic metres of rock, 265,000 cubic metres of concrete and 11,500 tons of steel were used.
The hydroelectric plant comprises 20 turbines, with an overall power of 3,200 MW, which guarantees an average yearly energy production of 1,700 GWh/year.
The most complex main phases of the dam's construction works were 3: the closing and deviation of the Paranà, a high-level engineering work to contain an average water flow of 12,000 m3/s, the execution of the internal dam, and that of the hydroelectric plant.
To guarantee the river's navigation, a concrete lock was built. 270 metre long and 27 metres wide, it allows ships to overcome the difference in level of 23.60 metres with a maximum draught of 3.65 metres.
Two structures that work as lifts ease the passage of fish species, drawn towards two collection channels by a water current that flows towards a dedicated basin that is lifted and emptied into the lake.
The dam is located at approximately 80 km downhill from Encarnaciòn and Posadas. With a length of 70 km, it extends for 18.7 km through the Paraguayan and Argentinian banks.
The reservoir created by the dam has an area of 1,600 km2 and a total volume of 21 billion cubic metres of water.
The hydroelectric plant houses 20 Kaplan turbines with a total installed capacity of 3,200 MW. The reservoir of the Yacyretá dam produces half of Argentina’s hydroelectric power, a renewable source that in 2023 accounted for 32.5% of national energy demand. The remaining demand was covered by natural gas (50.65%), wind power (11.65%), and oil (10.82%), while the other renewable sources, including nuclear, biomass, and solar, together accounted for 12.23% of annual demand. Overall, Yacyretá alone is able to provide about 60% of Argentina’s hydroelectric power and 22% of the country’s total energy needs.