CHENNAI: Tamil Nadu Generation and Distribution Corporation Limited (Tangedco) will set up two new natural-gas-based thermal units in North Chennai, said chief minister Edappadi K Palaniswami in the assembly on Monday. The units, each with a capacity of 730MW, will come up on the erstwhile GMR power plant premises in Basin Bridge. The GMR units were naphtha-based. Most thermal units of Tangedco are coal-based. Tamil Nadu has only 516MW of thermal plants that are natural gas-based and much of that is in the private sector. The two new projects are expected to cost more than Rs 5,000 crore, said sources. “We will prepare a detailed project report and seek loan from power finance companies before floating tenders. It will take at least five years for the units to generate power. The fuel will be sourced through a pipeline from the Indian Oil terminal at Ennore ,” said a senior Tangedco official. The GMR units were decommissioned in 2018. “The GMR site is about 30 acres. That is adequate for the LNG-based units,” said the official. The GMR units initially used diesel as fuel. Later it shifted to naphtha. The project became unviable when naphtha prices went through the roof. GMR had four units, each with a capacity of 46MW. Pollution was another reason for shutting down the GMR plant, said the official. The government has also allocated Rs 3,000 crore to replace equipment in all thermal units owned by Tangedco to prevent air and water pollution. “Based on the Supreme Court order, we had to replace several equipment in thermal units with modern ones so that fly ash does not pollute air in the areas. There are several complaints from residents living in areas close to thermal units about fly ash pollution,” said the official.