Tamil Nadu’s summer heat arrived with full force this April, triggering an immediate spike in electricity demand. The peak demand touched 21,307 megawatts (MW) on April 29. The same day, the State witnessed the peak power consumption of 471.45 million units (MU). This year, summer heat has led to the demand crossing the 21,000 MW regularly. Last year, the high demand was lower than the requirement of 2024. The maximum demand recorded in 2024 was 20,830 MW on May 2, and the highest consumption registered was 454.32 MU on April 30.

This year though, there have been no major power cuts, as is the norm when the demand surges. However, there are complaints of low voltage and supply disruptions in several areas of Chennai. The capital consumes almost 5,000 MW, and the maximum demand peaked to 4,769 MW on May 31, 2024.

Network upgraded

Over the years, power managers have commissioned projects to upgrade the transmission network. However, they say that despite the upgrades, disruptions do happen owing to glitches caused by the puncturing of underground cable networks or snapping of overhead cables.

A senior official of Tamil Nadu Power Distribution Corporation limited (TNPDCL) says the power demand this year has breached the previous maximum in all the districts owing to the heat. But the electricity department anticipated the demand and prepared well: the State has an installed capacity of nearly 40,000 MW, with 17,000 MW of thermal power and 13,000 MW of wind and solar energy.

In Chennai, people in the western suburbs of Avadi, Pattabhiram, Thandurai, and Thiruninravur have regularly been affected by low voltage and disruptions. The residential localities in Avadi, which was upgraded as a municipal corporation, has grown in the recent past. A proposal was made for taking the overhead cables underground for residents of the Tamil Nadu Housing Board (TNHB) flats. But the work has not been taken up. Consumer activist T. Sadagopan says it has been more than five years since the work on upgrading the 110-KV substation at Avadi to 230 KV started. But the project has been progressing slowly, resulting in supply disruptions in the nearby Pattabhiram and Thandurai. He points out that though the 110-KV substation at Pattabhiram was opened in 2007, improvement work has not been carried out regularly. A major fire occurred at the substation, which disrupted the supply at Pattabhiram for over 48 hours.

S. Dharanitharan, a resident of the TNHB locality at Avadi, says the Tidel Park at Avadi does not have a dedicated substation required to power the 21 floors. The Avadi-Poonamallee corridor has several multi-storey apartments and gated communities. But the gated communities are yet to have substations and transformers, as promised.

TNPDCL officials say they planned well by going in for the purchase of 1,500 MW of medium-term power to meet the peak-hour demand and avoid buying costly power from the exchange. The medium-term power accounts for 2,300 MW in the available total energy of 25,000 MW.

A senior official of TNPDCL says, “Every year, we expect an increase of 5% to 6% in demand; but this year, it has increased to more than 7%.” In its report, the Central Energy Authority has projected that the State would reach the peak demand of 21,959 MW. In anticipation, the TNPDCL installed substations in the city and on the outskirts and also converted the conventional transformers into 5,500 ring main units (RMUs).

Substations established

The energy department has established substations and upgraded the existing ones from Virudhunagar to north Chennai and Coimbatore for supplying power across the State. The 765-KV network would help minimise transmission losses, carry power in bulk, and ensure reliable supply. Enhancement work has been carried out at seven of the 400-KV substations, 11 of the 230-KV substations, and 60 of the 110-KV substations.

In the Coimbatore region, covering Coimbatore, Tiruppur, and the Nilgiris districts, the demand has touched an all-time high of 3,109 MW this year. The demand in summer is usually below 2,700 MW. But it grew gradually every month this year from 2,900 MW, and has crossed the 3,100-MW mark. The average daily consumption also peaked to 59.63 MU as against 57.39 MU in March. A substantial number of wind and solar energy plants in the highly industrialised Tiruppur and Coimbatore districts has helped in stable and steady supply to the city.

In Erode, the average demand touched 1,000 MW a day this summer. The daily demand during summer averages out at 800 MW in Erode and Gobchettypalayam. TNPDCL officials say solar power generation supports daytime consumption, while the increase in the demand at night hours is being met with adequate supply.

Namakkal residents are unhappy with the delay in the completion of the 20-MW Kolli Hills Hydro Electric Project, estimated to cost ₹338.79 crore. The foundation was laid in December 2018. The commissioning was scheduled for April 2021. The work was held up by the COVID-19 lockdown, and it slowed down again thereafter. The project is still under execution.

Solar energy has come as a major relief for the electricity department to manage the peak-hour demand in the Tiruchi region, which consists of Tiruchi, Dindigul, Perambalur, Ariyalur, and Pudukkottai districts. The region recorded the highest demand of 1,760 MW in the first week of May. The demand would normally be hovering around 1,500 MW-1600 MW in April and May.

According to official sources, there are no power outages in the region during the peak demand season, except in times of heavy rain. Private solar power units in different parts of the region have helped the power managers meet the demand at peak hours. “We have an installed capacity of 661 MW solar power by private players. The bright sunlight helped them utilise the infrastructure to maximise the output. It has helped us manage the daytime power demand,” says a senior official of the TNPDC in Tiruchi.

Rain to the rescue

Even as the power managers are confident of managing the demand in the delta districts, the spell of sudden rain has helped to bring down the demand. With Southwest monsoon setting in, the demand will slowly come down, the official adds.

TNPDCL officials are also hopeful that the wind energy generation from an installed capacity of more than 9,000 MW, which has remained stagnant so far in May, will pick up in the coming months. The demand in Tirunelveli and Tenkasi districts, which have more than 15 lakh power connections, has touched 500 MW this summer. The saving grace is the supply from the coal-based thermal power plants in neighbouring Thoothukudi. These plants have sufficient coal stocks. Hence, there is no hindrance to the generation. The wind power generators in the southern part of Tirunelveli district will start generating from May-end, with the onset of Southwest monsoon in Kanniyakumari district and neighbouring Kerala, says a senior official of the TNPDCL in Tirunelveli.

Shortage of components

However, officials are worried by the shortage of components, including electric poles and transformers, as also by a large number of vacancies for maintenance workers. A senior official of the Tiruneveli circle says more than 70% of the wireman and helper posts are vacant in Tirunelveli and Tenkasi districts. But the department is managing the situation with the available manpower and contract workers. However, any delay in filling these vacancies may cause issues in sorting out power interruptions, besides revenue loss.

Residents of Kanniyakumari want the pumped storage project at Velimalai expedited. The government announced the project in the 2025 Budget. As of now, only the tender has been floated for selection of a developer for the 1,000-MW/6,000-MW Velimalai Pumped Storage Hydro-Electric Project.

Total losses

The total losses of the electricity department has crossed the ₹1-lakh  crore mark, and the burden would only turn worse, thanks to the 200 units of free electricity announced by the new government, according to power managers. With the new scheme, the annual tariff subsidy for the domestic consumers alone is estimated to exceed ₹10,100 crore this financial year.

The State is known for its impressive performance in the human development indicators. But it is left with a poor energy sector caused by poor financial management. This has resulted in the power sector depending on grants and subsidies for generation and transmission projects.

According to the Energy Department’s demand for 2025-26 tabled in the Assembly, the tariff subsidy and grants had crossed the ₹30,000-crore mark for 2024-25 and now stand at ₹31,849 crore. The subsidy and grants have tripled from ₹10,834 crore for 2016-17.

Revenue fix

Navneeraj Sharma, an independent consultant, says Tamil Nadu has the potential to become an “electro-State”, combining genuine industrial depth with some of the country’s strongest renewable energy endowments. But its power sector is in urgent need of a revenue fix.

Mr. Sharma says the problem for TNPDCL lies not in providing free power but in how poorly demand forecasts, power purchase plans, and tariff designs are being done. Errors in load forecasting force the discom to buy short-term power at elevated spot prices, which translates into operating losses and a growing dependence on government funding. He adds that much of the domestic tariff structure benefits middle-class and upper-middle-class households rather than those who genuinely need support. This makes the fiscal burden harder to justify. He says that as Tamil Nadu’s renewable energy share grows, accurate consumer-level data — particularly for agriculture — will be essential for credible long-term planning.

Power managers say that when the government allows big industries to set up captive power units, the grid condition gets worse. Big industrial units avoid paying the high industrial tariff by establishing their own captive units, leaving the smaller units to pay high charges. Time-of-day pricing that rewards load-shifting to solar power-rich afternoons would give the industry a reason to stay on the grid rather than leave it.

(With inputs from M. Soundariya Preetha in Coimbatore, S.P. Saravanan in Erode, Rohan Premkumar in Udhagamandalam, M. Sabari in Namakkal, C. Jaisankar in Tiruchi, P. Sudhakar in Tirunelveli, and B. Shankari Nivethitha in Kanniyakumari.)