HTPP was envisioned as a power plant to serve the entire
South Caucasus, including Armenia. Construction began in 1963, and the plant became functional in 1966, with two turbines with a total capacity up to 100 MW. By 1969 two PT-100-130 type turbines of type "T-100-130" of the unit 2 started to operate, increasing heat distribution to 560 kcal/h (650 MW) and overall capacity to up to 300 MW. In 1974, the first block was combined with a second in close proximity, which had a capacity of 810 MW in four condensing power-generating units. The new Hrazdan State Regional Power Plant (SRPP) became, with 1110 MW total power, the most powerful power plant of
Armenia of those times. During its peak in the 1980s, the HTPP generated 6.85 TWh annually, with 7,300 hours (83%) clocked at total capacity. Between 1963 and the end of 2004, it produced 143 TWh electricity, but 12.3 Gcal/h energy in the form of heat. In 2003, the HTPP was passed to
Russian Federation to pay off the Armenian debt which was approximately US$31 million. The shares of the Hrazdan Energy Company went to the
Federal Agency for State Property Management of Russia. In July 2009, all stocks minus one share were acquired by the RUssian state-owned holding company Rosneftegaz. In May 2011, all shares were bought by Inter RAO UES. In 2015, Inter RAO UES sold the Hrazdan Energy Company to Cyprus-registered Liormand Holdings Limited, a part of Tashir Group owned by
Samvel Karapetyan. The deal will become fully in force in 2017. In 1986, the plan of construction of four additional units (units 5–8) with a
power generation capacity of 300 MW each was announced. Construction started in 1987, however, due to the
dissolution of the Soviet Union the construction works were halted. In 2006, the assets of the incomplete unit 5 was sold to
Armrosgazprom (now: Gazprom Armenia). The unit 5 as an independent power plant started operating in a pilot mode in January 2012, and since December 2013, it is in the commercial operation. ==Technical description (units 1–4)==