“According to a 2017 report by Tehran Air Quality Control Company, power plants in the capital had a  5.3% share in greenhouse gas emissions,” IRNA quoted Reza Samadi as saying.

This share may be higher in other provinces because unlike Tehran power stations that have stopped using mazut, those in other cities such as the Bandar Abbas use this dirty fuel, Financial Tribune quoted him as saying.

Mazut accounted for 45% of total power plant feedstock in 2013, but declined to 8% in 2015.

Currently, it has a meager share of feedstock because power stations are gradually replacing polluting fuels with natural gas as a cleaner energy resource.

Almost 95% of thermal power plants are now gas-fired. However, as gas consumption rises in the winter, more gas is needed for urban and suburban areas for heating purposes. For this reason, some power plants are forced to shift to liquefied fuels and this increases the level of air pollution, Samadi noted.

The official added that other industries (like cement factories) that use this type of polluting fuels are also infamous for increasing air pollution levels.

Diesel and mazut use, especially in the cold seasons, along with the phenomenon of temperature inversion, have a serious negative impact on air pollution, he said.

Thermal plants, including gas-fueled and combined-cycle ones, use as much as 280 million cubic meters and 170 mcm of gas per day in summer and winter respectively.

Domestic power plants consumed 67 mcm of gas in the last fiscal (March 2018-19), Samadi said, adding that diesel and mazut consumption in the period was 6 billion liters and 3.5 billion liters respectively.

Concerted Efforts 

In the past years, concerted efforts have been made to stop using mazut as feedstock in power plants.

Air pollution has become a very serious concern in Iran as is the case in many other countries and schools in major cities are often closed in the winter season due to the toxic air. For example, children in Tehran and other metropolises did not go to school for several days this month and hospitals were clogged when pollution reached unusually dangerous levels.

The government has ordered power plants and refineries to use gas instead of polluting feedstock due to huge gas reserves and the rising output from South Pars Gas Field.

Iran has abundant natural gas deposits and it is more cost-effective to use gas for power generation instead of dirty liquid fuels.

Gas production capacity has reached 700 million cubic meters a day, 630 mcm per day of which are currently extracted from the giant SP gas field.

South Pars, which is known as the North Dome in the Qatari territory, is being developed in 24 phases.