New Gas Turbine to Curb Tehran’s Water Consumption, Air Pollution

EghtesadOnline: The replacement of dilapidated gas turbine in 52-year-old Besat Thermal Power Plant in southern Tehran with a domestically-manufactured F-class gas turbine will help curb water consumption by 95% from 18 million liters to 800,000 liters per day, director of combined-cycle projects at the Thermal Power Plants Holding Company said.

News ID: ۷۸۶۵۴۵

28 June 2021

“The Besat facility consumes 18 million liters of water per day [18,000 cubic meters per day] to generate 1.2 billion kilowatts a year, accounting for a paltry 0.4% of the total annual national electricity output at 300 billion kWh,” Alireza Nasrollahi was also quoted as saying by the Energy Ministry’s news portal on Sunday.

The new gas turbine (MGT-75), manufactured by Iranian engineers at the Turbine Engineering and Manufacturing Company (TUGA), a subsidiary of MAPNA, the engineering and energy giant, is being installed at Besat.

Rapidly depleting water is extracted from six deep wells, as water shortage continues to pose a serious risk to the overcrowded capital where daily water consumption has exceeded 3.7 billion liters.

Nasrollahi said the aging plant uses the equivalent of water used by 72,000 people in the capital in one day.

Per capita water consumption in Tehran is 250 liters per day.

The estimated useful life of a power plant is 20 years. In addition to being outdated, another problem with Besat is that it has a wet cooling tower that is preferred in regions where water is plentiful, like the coastal regions.

In wet cooling towers, heat transfer is measured by decrease in the process temperature and a corresponding increase in both the moisture content and the wet bulb temperature of the air passing through the cooling tower.

According to the official, in areas like Tehran where access to water is limited, dry cooling techniques are used. As the name suggests, this relies on air as the medium of heat transfer, rather than evaporation from the condenser circuit. Dry cooling helps achieve minimal water loss.

When the facility opened half a century ago, Tehran was not struggling with chronic water scarcity. But conditions have changed and the population has jumped from three million to more than 10 million now.

NOx Emissions

Nasrollahi said the new turbine will also decrease nitrogen oxide (NOx) emissions by 94%.

Nitrogen oxides are a family of poisonous, highly reactive gases, which form when fuel is burned at high temperatures in power plants, industrial boilers, cement kilns and turbines.

“One specific feature of the MGT-75 turbine is that not only does it run on gas, but also can use hydrogen as feedstock.”

Taking advantage of hydrogen in mega cities like Tehran is of great importance as the metropolis suffers from endless air pollution.

Based on data from Iran Power Generation, Distribution and Transmission Company (Tavanir), efficiency of Besat Power Station, which annually uses 500 million cubic meters of gas as feedstock, had dropped to less than 25%.

Besat has a capacity of 200 megawatts – a small part of the 3,000 MW needed by Tehran. Other power plants in Tehran are Tarasht in the west and Rey in the south, which have a capacity of 800 MW and 65 MW, respectively.

“The new turbine will boost efficiency at least by 30% to 330 MW and gas consumption will be halved,” Nasrollahi said.

MAPNA CEO Abbas Aliabadi said MGT-75 is an industrial achievement and one of the best-in-class turbines in the world.

“The new turbine allows expansion of power production without the need for massive funding for new units,” he added.

Adding hydrogen to natural gas is a major step toward decarbonizing energy production as its combustion process emits less greenhouse gases, including CO2 and produces more energy.

“The fourth upgrade to the MGT-70 turbine has improved efficiency by 24% to 60% over the previous design. Most turbines used in Iran are from the E-class family and can be upgraded to MGT-75 with improved efficiency,” Aliabadi said.

Iran's Thermal Power Plants Holding Company signed a contract with MAPNA, the engineering and energy giant, to decommission the 52-year-old Besat Thermal Power Plant in southern Tehran.