Until 1968, Paraguay relied almost entirely on thermoelectric power. In that year, however, the first turbine was inaugurated at a major hydroelectric project at the juncture of the Acaray and Monday rivers. Planned jointly with Brazil and completed by an Italian company, this first stage of the project had a capacity of 45 MW; by 1976, the project was completed, with a capacity of 190 MW.
In 1973, Paraguay and Brazil agreed on the joint construction of the Itaipú power plant, the world's largest hydroelectric project. The plant, which became operational in 1984, has a generating capacity of 12,600 MW. By the end of 1982, the total cost (shared by the two countries) exceeded $20 billion; construction of the power plant and auxiliary facilities employed a peak force of 39,000 Paraguayan workers. Itaipú produces about 95% of Paraguay's electricity. Paraguay is entitled to 50% of Itaipú's output, but can sell unused power to Brazil; Itaipú produces about 75 billion kWh of electricity per year. Two new 700 MW turbines were slated to become operational in 2003.
Another 1973 agreement, with Argentina, called for the joint construction on the Alto Paraná River of the Yacyretá hydroelectric plant (320 km/200 mi downstream from Itaipú), with an installed capacity of 4,000 MW. The final agreement was signed in 1979, but it took another 16 years—until 1995—until the Yacyretá-Apipé complex was finally operational. Construction was delayed due to economic crises and disputes over contract awards, exacerbated by reports of cost overruns and high-level corruption. The Corpus Cristi hydroelectric project, another joint Argentine-Paraguayan venture, which would add another 3,000 MW of generating capacity, has been postponed, due largely to budgetary constraints in Argentina.
The National Electrical Administration (ANDE) manages the entire power system, which was nationalized in 1947. Total power production grew from 598 million kWh in 1975 to 53 billion kWh in 2000, with hydropower supplying nearly 100%. In the same year consumption of electricity was 1.9 billion kWh. Installed capacity in 2001 was 7,429 million kW.
Oil accounted for nearly half of Paraguay's total energy consumption in 2000. The country is entirely reliant on imports for its oil consumption (29,000 barrels per day in 2001). It is generally assumed that the Paraguayan Chaco contains oil, but explorations, which in the mid-1980s involved several international companies, have thus far proved fruitless. In March 2002, Paraguay and Bolivia signed a preliminary agreement to construct a pipeline to transport natural gas from Bolivia through Paraguay to Brazil.