Tamil Nadu thermal plants emit toxic gases beyond safety norms

The study also found that many thermal plants do not have the Flue-gas desulfurisation (FGD) system to monitor and control the quantity of sulphur dioxide emission. The study “Emission Watch – Status assessment of SO2 emission and FGD installation for coal-based power plants in Tamil Nadu,” was conducted along with the Centre for Research on Energy and Clean Air (CREA) and ASAR.

According to the study, only two out of the 40 thermal power plants (13,160 MW) currently operating in Tamil Nadu (1,200MW) are equipped with FGD. Steps have been initiated to procure FGD for eight power plants while no action has been taken for the remaining 30 plants.

As per the study, there are significant discrepancies between the data provided on the TNPCB website and the data available under the RTI received in April, May, and June 2021. Sulphur Dioxide (SO2) levels were shown to be very low even when air pollution control equipment was not fitted, according to documents obtained from the TNPCB under the RTI Act. Data obtained under the RTI Act further confirm that in many thermal power plants, Sulphur Dioxide, a gas known to be highly harmful to humans, has been emitted in quantities more than permissible levels. A senior Tangedco official said that the utility has invited tenders to install FGD in all its thermal power plants at north Chennai, Mettur and Thoothukudi. “We are hopeful of completing the installation of the emission controlling equipment within the deadline given by the Environment Ministry,” the official said, adding, however that the emission of SO2 is well within the permissible limits in its plants.

“The Union Environment Ministry set the standards for toxic gases released from thermal power stations in the country. A grace period of two years was given to reduce the toxic gas emission from the plants. But the grace period was extended, and by March 2021 it was announced that the grace period was extended until 2024/25,” Sunil Dahiya, a member who conducted the study from CREA, said.