Building Capacity: Tamil Nadu focuses on leveraging its renewables potential

Tamil Nadu is among the key renewable-rich states of India. According to the Central Electricity Authority’s data, as of September 2023, the state’s total power capacity stood at 37,958.41 MW. Of this, renewable energy accounted for 20,777.37 MW, including 2,178.20 MW of hydro capacity. The remaining comprises thermal (15,733.04 MW) and nuclear (1,448 MW). As per the Ministry of New and Renewable Energy, the total renewable capacity, excluding large hydro, co­mprises 10,300.62 MW of wind power, 7,082.49 MW of solar power, 1,043.7 MW of biopower and 123.05 MW of small-hydro power. The state’s 7 GW of solar ca­pa­city comprises ground-mounted so­lar (6,567.41 MW), rooftop solar (449.22 MW) and off-grid solar (65.86 MW). Its biopower capacity of over 1 GW comprises bio­ma­ss power/bagasse cogeneration (969.1 MW), biomass cogeneration (non-bagasse) (43.55 MW), waste-to-energy (6.4 MW) and off-grid waste-to-energy (24.65 MW).

In August 2023, the state’s total generation stood at 10,910.69 MUs, with renewable energy accounting for 37.42 per cent of the total. Wind generation during the same period was 2,427.66 MUs compared to 2,552.87 MUs in August 2022.  Meanwhile, from April to August 2023, the state’s cumulative generation stood at 53,655.82 MUs. Renewable energy acco­unted for 32.7 per cent of the total generation during this period. Wind generation from April to August 2023 was 10,653.64 MUs compared to 10,850.01 MUs during the corresponding period of the previous year.

In 1981, Tamil Nadu began developing wind power projects. The state was a pioneer in initiating the banking of wind power around the same time. As of September 2023, the state’s wind power capacity st­o­od at 10,300.62 MW, second only to Gu­jarat’s 11,094.02 MW. This year the state plans to add another 5,000 MW of wind capacity. Of this, 4,400 MW will be undertaken by new producers and the remaining 600 MW will be contributed by existing producers. With the state government planning to float a draft repowering policy soon, wind capacities in Tamil Nadu may surpass those of Guja­rat’s, going forward.

A key highlight of wind power development in the state has been decentralisation. Notably, around 65 per cent (approximately 8 GW) of the wind projects in the state are owned by commercial and industrial consumers for captive consumption. Around 2 GW of wind projects come under the feed-in tariff regime.

A key advantage for Tamil Nadu is the round-the-clock (RTC) availability of wind energy for three to four months (June to October). During these months, the state shuts down most of its coal plants. In April 2023, Tamil Nadu accounted for around 40 per cent of grid consumption. The development of offshore wind in the state will increase the availability of RTC wind power to seven to eight months (June to Febru­ary). With the addition of pumped storage projects, the state can move towards a year-round supply of 100 per cent green power.

Despite these advantages, several challenges remain for the wind power segment in the state. One, the issue of accurate forecasting and sc­heduling of wind power persists, leading to high deviations.  Two, the hybridisation of wind projects and solar projects faces challenges because RTC wind generation is available only for four months. Therefore, solar power is required for the remaining eight months when wind generation is low, in order to efficiently utilise the transmission network. Three, the state will face challenges in repowering old wind projects due to the limited number of large wind farms and the majority of capacity being decentralised for captive use, with consumers owning just one wind turbine. These customers may not be interested in repowering and owning larger turbines. The state will have to formulate a plan to club all ownerships, enabling them to collectively own a bigger windmill. Four, Tangedco’s finances have been drained, especially due to the banking of wind power.

Going forward, wind generation forecasting should improve in a bid to reduce significant deviations. For this, it is imperative to access weather and wind speed data, and be aware of windmill locations, the wind generation curve and the number of non-operating windmills at a given time.

With a potential of 35 GW for offshore wind deployment, Tamil Nadu’s wind journey seems to have only started.

Based on remarks by Rajesh Lakhoni, CMD, Tamil Nadu Generation and Distribution Corporation; and Beela Rajesh, Principal Secretary, Energy, Government of Tamil Nadu, at Windergy 2023