CHENNAI: After paying $10-$15 more for each tonne of imported coal for power plants during 2012-16, the state discom imported coal at $10-$15 less than the market rate in January 2018, documents sourced through RTI .

This was because Tamil NaduGeneration and Distribution Corporation (Tangedco) adopted a reverse auction method for the 2018 tender, which was not used for those during 2012-16, said Arappor Iyakkam, an anti-corruption NGO, in a press meet on Tuesday, alleging that this, along with over-invoicing and quality fraud during 2012-16 caused a loss of Rs 6,066 crore to the state exchequer.

Arappor convener Jayaram Venkatesan has filed a complaint with the Directorate of Vigilance and Anti-Corruption (DVAC) alleging a criminal conspiracy among the then electricity minister, senior Tangedco officials and private contractors who benefited from the deal. The private company which supplied coal at rates above the market rate during 2012-16 supplied it below the market rate in 2018, the RTI replies show.

When contacted, current power minister P Thangamani told TOI that the reverse auction had indeed given them coal at a rate lesser than the market price. “It is a policy change,” he said. Asked if this indicated a multi-crore loss to the exchequer during the previous purchase, he said that a reverse auction process then could have given a higher price too. “We followed what other states also implemented,” he said.

M Saikumar, who was Tangedco chairman and managing director from 2014 till March this year, did not respond to calls or messages. He is now principal secretary to chief minister Edappadi K Palaniswami.

As reported by TOI, Tangedco not following a reverse auction method for identifying prices for the imported coal had been questioned by Comptroller and Auditor General (CAG). This was despite another state PSU, Tamil Nadu Newsprint and Papers Ltd (TNPL), using the reverse auction method to bring down its coal importbill.

Jayaram said that as per his calculations for the 2012-16 orders, Tangedco lost Rs 2,177 crore due to over-invoicing compared to market rate for 2.44 crore tonnes, Rs 2,395 crore due to the difference in quality, which was extrapolated from CAG’s calculations, and Rs 1,494 crore loss if coal had been imported at $10 less than the market rate.