Iran has begun supplying 391 million liters of low-sulfur mazut to four thermal power plants, marking one of the clearest signs yet of the government’s push to improve fuel quality ahead of the winter demand peak.
The announcement was made by Mohammad Sadeq Azimifar, CEO of the National Iranian Oil Refining and Distribution Company (NIORDC), who said the move is part of the government’s plan to upgrade petroleum products and strengthen the country’s fuel-supply chain.
Iran’s power sector relies heavily on natural gas, but winter shortages routinely force power plants to switch to liquid fuels—primarily mazut and gasoil.
Although only 14 power plants are officially permitted to burn mazut, its use has surged. According to public data, Iran’s mazut consumption has nearly tripled in six years, rising from about 14 million liters/day in 2017 to more than 43 million liters/day in 2024.
One of the most critical issues about mazut is its sulfur content. Conventional Iranian mazut often contains up to 3.5% sulfur, far above global norms. International standards—especially in the marine sector—place the limit at 0.5%, while Iran’s own “high-quality” threshold is considered below 0.8% sulfur. The burning of high-sulfur mazut is directly linked to elevated SO₂ emissions, which worsen smog, respiratory illnesses, and winter air pollution across major cities.
Low-sulfur mazut, now supplied in volume for the first time, is significantly cleaner and allows plants to operate when gas supply is diverted to households.
Strategic Significance
Azimifar said the new deliveries will both secure winter electricity output and reduce environmental harm, while also limiting the use of gasoil—a more expensive and strategically sensitive fuel.
The 391-million-litre supply is designed to stabilize the energy system during Iran’s annual gas crunch. Iran produces unusually large amounts of mazut because many refineries lack modern upgrading units; some facilities convert as much as 30% of crude into mazut compared to the global average of 4%–8%.
The shift toward low-sulfur production signals early steps toward reform, though refinery upgrades and long-term investment remain essential.
