Los Nihuiles Hydro Power Plant (‘HINISA’)

Located on the Atuel River in the province of Mendoza, HINISA operates the Los Nihuiles System, consisting of three dams, three hydroelectric power plants (Nihuil I, Nihuil II, and Nihuil III), and a compensatory dam. With a 265 MW installed capacity, representing 0.6% of Argentina’s total capacity, HINISA covers approximately 40 km, and its height ranges between 754 m and 1,251 m above sea level. From 1990 to 2025, its historical average annual generation was 767 GWh, with a record high of 1,250 GWh in 2006 and a record low of 283 GWh in 2025, due to the storm that occurred on January 11, 2025, which inflicted severe damage in the Atuel Canyon, leaving the Nihuil II and Nihuil III power plants out of service and inoperative. Insurance under the Operational All Risk policy was activated, notifying authorities and assessing the condition of the affected equipment. All analyses required for their recommissioning have already been completed. Pampa holds a direct 52% stake in HINISA.

HINISA’s 30‑year concessions expired on June 1, 2024, one granted by the Province of Mendoza for the use of assets and water resources, and another by the National Government for electricity generation. On May 27, 2024, the Government of the Province of Mendoza and the SE extended the concessions for 12 months (DNU No. 1,021 and Resolution SE No. 83/24). As a result of the incident in January 2025, on May 26, 2025, the Government of the Province of Mendoza declared a state of emergency for the system and extended the transition period by an additional 14 months (Law No. 9,630). Pampa stated that such extension required an agreement with HINISA and, in the absence of a definition, HINISA decided to continue operating to safeguard the concessioned assets, ensure the electricity supply, and protect personnel and facilities. Operational continuity does not imply that HINISA accepts the extension, nor that it assumes new obligations or liabilities, nor that it waives any of its rights under the Concession Agreements. The concessions currently expire in July 2026.

On March 8, 2025, the National Government and the Province of Mendoza agreed to jointly tender the HIDISA and HINISA concessions as a single business unit. The Agency for the Transformation of Public Enterprises was appointed to coordinate and conduct the tender process within 60 business days. As of the date of this annual report, the tender schedule has not been published.

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The following chart shows certain relevant statistical data on HINISA:

Note: Gross Margin before depreciation and amortization.

Technical Data