Evening Power Shortages Widen in India as Solar Fades and Thermal Plants Stay Offline

India's electricity grid is increasingly under strain in the evening hours, even though daytime supply remains comfortable. As temperatures during the May 2026 heatwave have crossed 45 degrees Celsius in several states, demand has surged. Solar generation is helping cover the day, but after sunset the gap between demand and supply has widened sharply.

Industry experts describe the 6 pm to 10 pm window as the hardest part of the day to manage. The sun has set, rooftop and grid-scale solar generation falls to zero, but household demand for air conditioning, lighting and cooking stays high. According to data from the Grid Controller of India, the country recorded an energy shortage of 15.87 million units (MUs) on a single day this week. That is enough electricity to power around three million homes for a full day.

The supply pressure has been made worse by the fact that nearly 40 gigawatts (GW) of thermal generation capacity, or 15 per cent of India's 239 GW thermal fleet, is currently under forced outage due to technical faults. The peak demand recently touched a record 270.82 GW on 21 May, with the evening peak at 246 GW.

The shortfall is concentrated in the northern and western regions. Maharashtra, Haryana and Punjab have seen the largest cuts, driven by a mix of weak storage capacity, plant outages and an over-reliance by distribution companies on short-term power exchanges instead of long-term purchase agreements. Punjab is expected to see further pressure once the paddy sowing season begins on 1 June, with peak demand projected to climb to about 17,500 MW from 16,600 MW last year.

The structural answer being discussed is battery energy storage. A four-hour battery charged with cheap midday solar and discharged during the evening peak is now seen as commercially viable. Government estimates place planned battery storage at 47 GW by FY32, but the current installed capacity is only 795 MWh, a tiny fraction of the target. Discoms have been slow to commit because batteries get heavy use only on a few peak days a year while costs are paid through the year.

The episode highlights an awkward truth of India's energy transition. Solar capacity has been added rapidly and the country is well placed during the day, but firming options like batteries, pumped hydro and well-maintained thermal capacity have not kept pace. The India Energy Exchange real-time prices have repeatedly hit the regulated cap of ten rupees per unit this month, even as a few days of rain and cooler weather briefly pushed prices to zero, an extraordinary swing in a single calendar month.