Acaray Dam, Hydroelectric dam in Hernandarias District, Paraguay

Acaray Dam is a hydroelectric structure built across the river to generate electricity for the region. The installation features concrete walls that contain a large reservoir behind its main barriers.

Built between 1961 and 1969 under Alfredo Stroessner's modernization programme, with Brazilian support, the Acaray plant was one of Paraguay's first major hydroelectric works. Its first machine entered service over 48 years ago, and ANDE is now modernizing and repowering equipment nearing the end of its useful life.

The Acaray Dam is depicted on Paraguay's 50-guaraní coin, not on banknotes. The coin shows the dam as a symbol of the country's hydroelectric development, which began with this plant under Alfredo Stroessner's government in the 1960s.

The plant sits in Hernandarias beside the Itaipú superhighway, a few kilometres from where the Acaray River meets the Paraná. It is a working facility run by ANDE, so access is not open to the public; the reservoir surface lies at 185.3 m and the tailwater at 115 m. Ask ANDE or local authorities in Hernandarias about any permitted viewpoints before travelling.

The facility operates with a specialized frequency conversion station that allowed electricity exchange between Paraguay and Brazil at different electrical frequencies. This technical arrangement connected two separate national power grids.