“The facility is designed to use both gas and mazut. But according to a court order, the plant is banned from using mazut,” the Energy Ministry news website quoted Masoud Sheikh as saying.
“We are banned from burning mazut for electricity generation for the past eight years due to environmental concerns. The Department of Environmental regularly monitors the plant's chimneys and measures pollution levels so that it does not exceed the allowable limit,” Sheikh said.
Speaking about video clips on social media showing smoke billowing from the Besat plant, he said: “What is seen over the plant is not smoke. It is water vapor.”
“Besat Thermal Power Plant in south Tehran has three steam units and three cooling towers. When cold water is poured on the hot water of the plant to reduce the temperature, steam in the process is emitted from the cooling towers. The vapor is mistakenly taken for smoke from burning mazut,” he noted.
Almost 95% of thermal power plants across Iran 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.
Mazut use, especially in the cold seasons, along with the phenomenon of temperature inversion, has a serious negative impact on air pollution.
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.
Regarding gas consumption in Besat plant, Sheikh said it uses 1.5 million cubic meters of gas a day, which is negligible compared to the 120 million cubic meters consumed daily in Tehran.
“Although the plant consumes gas and has low emissions, part of the carbon dioxide produced is separated, processed and delivered to beverage factories.”
Despite the use of gas, it is important to note that the Besat plant was built more than half a century ago and has low efficiency. This means that it consumes more gas for generating electricity than high-efficiency units.
“Efficiency of Besat power plant is 30% and renovation is underway. New units are built and when operational the old systems will be dismantled. Maximum production capacity now is 210 megawatts but will surpass 400 MW” with innovation and new technology, he said.