Costa Rica depends upon imports for an overwhelming proportion of its petroleum needs; this dependency has contributed greatly to the inflationary trends of recent years. Because of a scarcity of fuels, Costa Rica depended on hydroelectric energy for about 86% of its light and power in 1999. Installed capacity as of 2001 was 1,611,000 kW, more than double the 1973 total. In 2000 production of electricity totaled 6.6 billion kWh, of which 82.5% was from hydroelectric power, 1.2% was from fossil fuels, and the remainder was from other sources. Consumption of electricity in 2000 was 5.9 billion kWh. In February 1999, construction of the 55-MW geothermal station at Miravalle was completed. Preliminary work for the 90-MW Toro hydroelectric complex is now underway. Two other installations include the 157-MW Arenal and the 174-MW Corobisi plants.
Most of the nation's electricity is generated by the Instituto Costarricense de Electricidad (ICE), an autonomous government corporation, which owns and operates the central transmission network. In the early 1960s, the World Bank helped finance construction of a 30,000-kW hydroelectric plant on the Río Macho, about 50 km (30 mi) from San José, the installation of 9,000 kW of diesel generating capacity at Colima and Limón, and the extension of the central transmission network. These facilities provided a 40% increase in generating capacity in Costa Rica's central zone. In 1991, Costa Rica's hydroelectric potential was estimated at 25,450,000 kW.