India’s Power Grid Faces New Challenge as Solar Growth Shifts Focus from Capacity to Flexibility: EAC-PM Paper

India's rapidly expanding renewable energy capacity has transformed the country's electricity landscape, but the biggest challenge for the power sector is no longer generating enough electricity. Instead, the focus has shifted to ensuring electricity is available at the right time and that the grid can respond quickly to changing demand, according to a new working paper released by the Economic Advisory Council to the Prime Minister (EAC-PM).

The paper titled 'The Duck and The Camel: Tracing the Net Load on the Indian Power Grid,' examines how increasing solar power penetration is reshaping India's electricity demand profile and argues that rapid deployment of energy storage systems is now critical for maintaining grid stability.

The report notes that India's electricity demand reached an all-time record of 270.8 GW at 3:45 PM on May 21, 2026, while demand had stood at 224.1 GW at 8:00 AM the same day. The grid therefore absorbed an additional 46.7 GW within less than eight hours, highlighting the increasing volatility in electricity demand. At the same time, electricity prices on the Indian Energy Exchange (IEX) reflected a sharp mismatch between daytime solar availability and evening demand. While electricity scheduled for delivery at 1:00 PM cleared at INR 1.56 per unit, prices surged to the market ceiling of INR 10 per unit at 6:30 PM after solar generation declined.

According to the paper, these trends indicate that India's power system is increasingly constrained by flexibility rather than installed generation capacity. As solar generation rises during the day, conventional power plants are required to rapidly reduce output in the morning before ramping up sharply after sunset when solar generation disappears but electricity demand remains high. The report argues that storing surplus electricity generated during solar hours and releasing it during evening demand peaks offers the most effective solution to this growing imbalance.

The study introduces two distinct seasonal patterns in India's net load curve. During summer, the country's power demand resembles the globally recognised 'duck curve,' characterised by a deep dip in conventional power demand during midday due to high solar generation followed by a steep evening ramp as solar output declines. In winter, however, the grid exhibits what the report describes as a 'double-humped Bactrian camel,' with electricity demand peaking both in the morning and evening while solar generation creates a midday trough. These seasonal demand patterns are based on high-frequency 15-minute grid data collected over multiple years.

The report finds that the summer duck curve has become considerably steeper over the past three years. Between May 2023 and May 2026, the morning ramp-down of conventional generation nearly tripled from around 18 GW to 53 GW, while the evening ramp-up doubled from approximately 36 GW to 74 GW. During winter, both the morning descent into the midday trough and the evening climb increased to around 64 GW, demonstrating that the flexibility requirements of the grid are rising rapidly as solar capacity expands.

Electricity market prices also mirror these changing demand patterns. The paper notes that the average daytime electricity price in May fell from INR 2.81 per unit in 2023 to INR 1.11 per unit in 2026, while evening prices increased from INR 8.08 per unit to INR 9.71 per unit over the same period. Consequently, the spread between the lowest and highest daily electricity prices widened significantly, reinforcing the growing value of shifting electricity from midday to evening through storage technologies.

Another major concern highlighted in the report is increasing solar curtailment. During May 2026, approximately 24 GWh of solar electricity was curtailed every day, equivalent to more than one-quarter of Delhi's average daily electricity consumption. At the same time, the grid experienced shortages predominantly during non-solar hours. Between April and May 2026, electricity shortages occurred on 36 out of 61 days during evening and night-time demand peaks, compared with only six days during peak solar hours, indicating that India's electricity shortages are increasingly concentrated after sunset rather than during the day.

The paper concludes that India's existing storage infrastructure remains insufficient to manage these growing fluctuations. It estimates that flattening even half of a typical summer evening demand ramp would require around 130 GWh of energy storage discharge, whereas India's combined pumped-storage and battery fleet discharged only about 23.8 GWh per day during May 2026. While pumped-storage projects have nearly achieved their planned capacity targets, the report identifies a significant shortfall in battery energy storage deployment despite recent additions that have increased installed Battery Energy Storage System (BESS) capacity to 2.7 GW.

The authors also point to ongoing policy reforms that could help address the flexibility challenge. They note that the draft Electricity (Amendment) Bill, 2025 and the draft Electricity (Rights of Consumers) Amendment Rules, 2026 propose recognising energy storage systems under the Electricity Act, expanding power markets through mechanisms such as contracts for difference, strengthening non-fossil purchase obligations, introducing demand response programmes, implementing time-of-day tariffs and encouraging prosumers to integrate battery storage with rooftop solar systems.

While supporting India's continued expansion of renewable energy, the report cautions that accelerating solar deployment without corresponding investments in battery storage and other flexibility measures will place increasing stress on the national grid. It concludes that India's energy transition now depends not only on adding more renewable capacity but also on developing sufficient storage and market mechanisms capable of shifting surplus daytime solar energy to periods of peak demand.