Rising heat & humidity pushing Delhi’s peak power demand to record levels

Delhi witnessed a significant jump in temperature-related electricity demand in the last 12 months, ending June 22, 2024, as the national capital’s hot and humid days virtually doubled, thereby pushing up the demand for cooling.

According to a brief by the Institute for Energy Economics and Financial Analysis (IEEFA), the national capital territory witnessed a record 40 hot and humid days in the 12-month period till June 22 compared to 24 days in the corresponding period in 2022-23.

The institute used the wet-bulb temperature (WBT), which is a measure of both heat and humidity, as a yardstick. It has highlighted a marked increase in the number of very hot and humid days (using 30°C WBT as a threshold).

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Delhi witnessed a sizeable jump in temperature-related electricity demand in the last 12 months (up to June 22, 2024), with peak demand increasing by 711 megawatts (MW) on the hottest and most humid days, and by 506 MW on cold and dry days. The demand rose by only 188 MW on days when the temperature and humidity were moderate, it added.

“On hot and humid days, when the WBT was 32.5°C, the year-on-year peak demand increase was 3.8x greater than it was on moderate days (17.5°C WBT), and on cold, dry days (when WBT was 7.5°C), it was 2.7x higher,” the IEEFA brief pointed out.

Air conditioning accounts for around 30-50 per cent of the total annual energy expenses of a business or a household.

Climate change

WBTs above 35 degrees Celsius have been considered impossible to survive in for more than a few hours. Yet, studies increasingly predict temperatures exceeding this threshold in various parts of the world.

One of the key takeaways from IEEFA’s analysis is that power demand is lowest on moderate days, but it increases substantially on hotter, humid days, reflecting the demand for air conditioning and fans, while also increasing (though much less) on colder, drier days when the demand for heaters is high.

Source: IEEFA | Photo Credit: Source: IEEFA

Besides Delhi, the Northern Region also showed a similar disproportionately high increase in demand in the last 12 months, relative to the preceding year, on hot and humid and (to a lesser extent) cold and dry days.

For peak demand, the year-on-year increase at 32.5°C WBT was 2.8 times higher than that at 17.5°C WBT, and for 7.5°C WBT, it was about 1.8 times higher than for such moderate days.

With Delhi and the northern region now in the eye of brutal heat waves and heavily reliant on importing power at such times, it would be justified to accord priority to an effective and rapid transition, the IEEFA brief emphasised.

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The burden cannot realistically be borne only or even primarily by thermal plants. Now operating much closer to peak capacity than in recent years, they have much less headroom to boost generation further during heat emergencies.

Scaling up utility-scale solar growth is essential. Acceleration of rooftop solar programme to increase generation close to loads may become not just desirable but a key component in a series of measures to supply additional power, especially in urban areas. In rural areas, there is still a place for locally controlled distributed renewable energy (DRE) to ease the burden on grid power.

Delhi’s power demand

Delhi witnessed record breaking power demand in the current summer season (April to June 2024). For instance, the national capital’s peak power demand met, during the day, rose to an all time high 8,656 MW on June 19, after scaling 8,647 MW a day earlier.

The capital city’s peak power demand hit the 8,000 MW mark for the first time on May 22, 2024. Between May 22 and June 19, 2024, peak power demand surpassed 8000 MW on 9 occasions. Similarly, the city’s peak demand rode past the 7,000 MW mark a record 31 times between May 1 and June 19.

According to the Delhi Economic Survey report 2023-24, its electricity consumption rose from 25,593 million units (MU) in FY12 to 35,042 MU in FY23. Delhi has its unique load pattern and peak load problem due to predominant share of domestic consumption and extreme weather conditions.

During FY12 to FY23, the number of electricity consumers in Delhi increased from 43.01 lakh to 68.51 lakh.

The total power purchase in Delhi is 40,997 MU in FY23. While 9.65 per cent of the total power purchase is sourced from own generation by Delhi government power plants, 90.35 per cent is purchased from central government and other sources. 

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