Chennai: Carbon emissions from the Tamil Nadu Generation and Distribution Corporation (Tangedco) touched a record high of 83.05 million tonnes of CO₂ in 2023-24, mainly due to increased reliance on coal, lignite and short-term market purchases, a new study has found. According to a report by Auroville Consulting, authored by Akanksha Galagali, which analysed seven years of power purchase data using data from the Central Electricity Authority (CEA), fossil fuels continued to dominate the state’s energy mix, accounting for 52% of power purchased in 2023-24. Despite a marginal increase in solar and hydro, Tangedco’s renewable energy (RE) purchases declined to just 12% in FY24, below the 27% renewable purchase obligation (RPO) target. The state utility’s grid emissions factor (EF) also worsened, reaching 0.75 tonnes of CO₂ per megawatt-hour, higher than the national average of 0.73 tCO₂/MWh. Lignite emerged as the most emissions-intensive fuel, with an EF of 1.38 tCO₂/MWh.
The report said Tangedco’s carbon emissions have increased by 47% since 2020-21, when emissions were at their lowest due to a pandemic-related drop in demand. This increase is due to a 28% increase in fossil fuel purchases and a surge in short-term purchases, which grew 150% in seven years. Despite a 29% increase in total renewable energy purchases since 2017-18, the last three years saw a stagnation. While solar and hydropower made a large contribution to renewable supply, wind and biomass remained marginal. Nuclear power maintained a modest but stable share of around 10%. The study highlights declining operational efficiency at gas-based thermal power plants, where declining procurement ratios have not led to emissions reductions. It recommends that Tangedco modernise its ageing thermal power fleet, phase out the use of lignite, and improve sustainability of renewable energy generation to meet climate goals. The report also calls for integrating emissions intensity as a key criterion in future power procurement and planning, saying Tamil Nadu’s power demand is likely to continue growing in the near future.
