Battery storage key for India's grid stability, says EAC-PM report

An EAC-PM report states India's power grid is now constrained by flexibility, not capacity, due to solar power's growth. It identifies battery storage as the key solution to manage fluctuating demand and ensure grid stability.

India's power grid is no longer primarily constrained by electricity generation capacity but by its ability to respond quickly to changing demand, making battery storage the key solution for ensuring grid stability, according to a report by the Economic Advisory Council to the Prime Minister (EAC-PM).

The report 'The Duck and The Camel: Tracing the Net Load on the Indian Power Grid' brought out in the EAC Working Paper Series, said the rapid growth of solar power has fundamentally changed the nature of stress on India's electricity system. It stated that "the best way to smoothen these fluctuations in demand and price is to store electricity when it is abundant and release it when it is scarce."

The 'Duck and Camel' Phenomenon

According to the report, India's electricity demand is increasingly witnessing sharp fluctuations within a single day as solar generation rises during the day and falls rapidly after sunset. To examine this trend, the report mapped the net-load curve -- total demand met minus solar output -- using high-frequency grid data at every 15-minute interval over a 24-hour period.

It analysed individual summer and winter days and then compared monthly averages across years to identify structural changes in the power system. The report found that during summer, when cooling demand is high and solar generation is at its strongest, the net-load curve resembles the globally recognised "duck curve", with a deep midday trough followed by a steep evening rise.

In winter, however, the pattern changes into a "double-humped Bactrian camel", with electricity demand peaking in the morning and again in the evening, separated by a midday dip supported by solar generation.

Shift From Capacity to Flexibility

The report said these changing demand patterns have shifted the focus from adding generation capacity to improving the flexibility of the grid. "The grid is now bound by when it can generate the electricity required, and how fast it can change what it generates. In other words, the active constraint for the grid has shifted from generation capacity to flexibility. Storage is the obvious solution. However, the storage gap is large and needs to be filled quickly," the report said.

India's Massive Storage Gap

According to the report, flattening even half of the evening rise in electricity demand during a typical summer day would require about 130 GWh of battery discharge between 1 pm and 8 pm. However, India's existing storage infrastructure remains significantly below the required level.

The report noted that India's entire pumped-storage and battery fleet discharged only about 23.8 GWh across an average day in May 2026. It added that "the shortfall is overwhelmingly a battery shortfall." Against the National Electricity Plan's projection of 8.68 GW of grid-scale batteries for 2026-27, only 0.27 GW was operational till January 2026. While recent capacity additions have increased Battery Energy Storage System (BESS) capacity to 2.7 GW, the report said "the gap still remains large."

California's Battery Success Story

The report also cited California as an example of how battery storage can reduce pressure on the electricity grid. It said California's battery fleet, capable of discharging more than 10 GW, stores excess solar power during the day and releases it during the evening, reducing the evening net-load swing from nearly 28 GW to about 10 GW.

According to the report, this is the capability India will require as its solar power capacity continues to expand. The report concluded that expanding battery storage alongside renewable energy capacity would be essential to reduce grid stress and improve the flexibility of India's power system.

(ANI)

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