The two units, with a combined capacity of 320 megawatts, cost $260 million, IRNA reported.
The third 160 MW steam unit is scheduled to come on stream by the end of the current fiscal year (March 2020).
“Shirvan Power Plant has six gas units, each with a capacity of 155 MW (totaling 930 MW). When all the three steam units become operational its overall capacity will reach 1,410 MW,” Shirvan governor said.
Amin Reza Merati noted that 30% of the production capacity of the plant can supply the needs of North Khorasan Province (population 960,000) and the remaining 70% will go to other provinces.
Each steam unit will annually help save the plant 250 million cubic meters of natural gas worth $40 million.
The addition of steam units to the plant is in line with a plan to convert simple-cycle plants into combined-cycle ones.
A combined-cycle power plant uses both gas and steam turbines to produce up to 50% more electricity from the same fuel input than a traditional plant. The waste heat from the gas turbine is rerouted to a steam turbine, which in turn generates more power.
Measures have been taken in recent years to convert conventional plants into combined-cycle ones to improve efficiency and reduce pollution and costs.