Chennai: Tamil Nadu, where sticky summer nights increasingly deny relief even after sunset, has emerged as one of India’s biggest heat-and-humidity hotspots, a trend now quietly reshaping electricity demand and intensifying urban heat stress.A report released by Climate Trends, ‘From Heatwave to Grid Wave’, ranked Tamil Nadu second in the country for “compound hot-humid days”, periods when high heat and humidity occur together, between 2015 and 2024, behind only Uttar Pradesh. The report noted that 2015–2019 saw about 14,086 such days nationally, rising to 16,970 between 2020 and 2024, with 2024 recording the highest annual count.The findings are relevant for Chennai and other coastal parts of Tamil Nadu, where humidity worsens discomfort even when temperatures are not extreme. “Electricity demand is often shaped by combined heat plus humidity, not temperature alone,” the report said, adding that this is particularly significant in “coastal metros, where oppressive night conditions can drive sustained cooling use”.Climate Trends said India’s record peak electricity demand of 270GW in May reflected a growing shift in consumption patterns as cooling needs increasingly overtake industrial demand growth. “Residential cooling demand is now overtaking industrial power demand growth,” the report said, warning that rapid urbanisation is turning cities into “giant heat traps”.The report said one of the most important urban heat island effects is elevated night-time temperature, which extends cooling demand late into the night as buildings retain heat and households increasingly shift from fans to air conditioners. By 2030, air-conditioner use could reach 40% of Indian households, it added.According to the Tamil Nadu Climate Tracker, power demand in the state has steadily increased over the past decade. April, typically among the hottest months across many districts, has recorded a sharp rise in peak demand from 12,969MW in 2015-16 to 20,148MW in 2025-26. Ten years ago, the monthly peak demand was highest in the month of March, but it shifted to April since 2023. The tracker also shows that around 38% of the state’s electricity is generated from renewable sources, including 25.6% from wind and 12.8% from solar, while coal-based plants continue to account for the largest share of generation at 43.6%.Climate Trends suggested measures such as cool roofs, reflective pavements, rooftop solar, and blue-green infrastructure to reduce urban heat and ease pressure on power networks.
