The Los Nihuiles complex is located on the Atuel River in San Rafael and consists of four hydroelectric plants totaling 288-290 MW of installed capacity, representing approximately 0.7 percent of Argentina’s total generation capacity. The system spans 40 kilometers along the Atuel Canyon with a vertical drop of 460 meters. Nihuil I comprises the El Nihuil reservoir, inaugurated in 1947, and the 75 MW Ing. Juan Eugenio Maggi plant. Nihuil II includes the Aisol dam, built in 1969, with 131.2 MW capacity. Nihuil III consists of the Tierras Blancas dam and a 52 MW facility. The Valle Grande reservoir and 30 MW Nihuil IV plant, added in 1997, complete the complex. Between 1990 and 2017, the system generated an average 838 GWh annually, reaching historical peaks of 1,250 GWh.
The new tender follows expiration of the original concession, which was temporarily extended to ensure orderly transition while the new operational and investment framework was defined. Provincial authorities are pursuing what they describe as a superior project that incorporates current technology, efficiency improvements, and future generation expansion possibilities rather than limiting scope to existing infrastructure repair. The long-term concession is designed to restore operational capacity, enhance energy performance, and increase provincial royalty revenues. The tender will also integrate Nihuil IV fully into the general complex scheme, unifying operation of all plants under a single management model.
Separately, Resolution SE N° 400/2025 enables hydroelectric facilities including Los Nihuiles to participate in Argentina’s term market (MAT), allowing direct power supply contracts with large users. The complex is expected to contract 220 MW under normal operating conditions through this mechanism. Private sector interest has emerged, with firms including International Power Services expressing attention to the asset.
This article was curated and published as part of our South American energy market coverage.
