India's power deficit hits 10-year Sept high as weak monsoon drains hydropower and heat lifts demand

India's electricity deficit surged to its highest level for September in nearly a decade as weak monsoon rains depleted hydropower reservoirs and hot weather kept demand high, according to a Bloomberg News analysis of data from the Grid Controller of India.

Daily peak shortfalls during evening hours exceeded 2 gigawatts for more than half of September and occasionally crossed 6 gigawatts. The maximum daily deficit reached 7.7 gigawatts, higher than the shortfall recorded during the hotter months earlier this year.

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The combined energy shortage was the worst for September since 2017.

The country's monsoon brought about 13% less rain than normal between June and September, making it the weakest season since 2015. The strong El Niño weather pattern contributed to the shortfall.

The weaker rains left large parts of the country hotter, pushing up demand for air conditioning. At the same time, hydropower generation fell nearly 16% in September from a year earlier, its fifth consecutive monthly decline.

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Normally, electricity demand and industrial activity ease during the June-September rainy season. That gives power producers time to rebuild coal stocks. This year, however, demand remained elevated from March.

Uneven rainfall also flooded some coal-mining areas in eastern India, disrupting production and transport. Coal inventories at power plants fell steadily to their lowest level in nearly three years.

Daily reserves have more than halved from a year earlier and have declined continuously since July 12, according to power ministry data compiled by Bloomberg. About 40% of the 191 plants surveyed had less than a quarter of the coal stocks they require. On average, plants had about a week of reserves.