In the first half of the 20th century, the electricity sector was in hands of private companies, which built local and regional supply schemes.
Besides hydroelectric power, Venezuela also relies on natural gas and petroleum, contributing 25% and 11%, respectively, to the total electricity output that year.
[1] From 1980 to 2000, Venezuela's electricity consumption almost tripled from about 30 to 88 terawatt hours (TWh), primarily met through hydroelectric expansion, while thermal capacity stayed flat.
By 2002/03, electricity theft and drought-induced shortfalls led to a mid-2000s policy shift towards enhancing thermal plant capacity, which nearly doubled.
The largest hydroplant is the Guri dam with 10,200 MW of installed capacity, which makes it the third-largest hydroelectric plant in the world.
The largest power companies are state-owned CVG Electrificación del Caroní [es] (EDELCA), a subsidiary of the mining company Corporación Venezolana de Guayana (CVG), and Compania Anonima de Administracion y Fomento Electrico (CADAFE [es]) accounting respectively for approximately 63% and 18% of generating capacities.
Oficina de Operación del Sistema Interconectado (OPSIS), jointly owned by the four vertical integrated electric companies, operate the SIN under an RTPA[clarification needed] regime.