The construction of the nuclear power plant was launched in 1969. Unit 1 plant was commissioned on December 22, 1976, while unit 2 was commissioned on January 5, 1980. However, it was temporarily closed in 1989 after the 1988 Armenian earthquake for environmental reasons. Energy shortages caused by its closure forced the Armenian government to reopen the plant in 1993. Unit 2 reactor was brought back into operation on October 26, 1995. Nowadays, the Metsamor plant generates 40% of Armenia's energy needs. The plant was heavily modernized and redeveloped between 2003 and 2015. The construction of a 3rd unit is planned to replace the old reactors by 2026.