As soaring temperatures push India’s peak power consumption to record highs, the stress on the grid is becoming most pronounced at night, when nearly 150 GW (giga watt, or 1000 mega watts) of solar capacity goes offline after sundown.Data from the Grid Controller of India (Grid India) shows that there has been a shortage in meeting peak demand the past few days during non-solar hours, which typically refers to the period between 6 PM and 6 AM, when solar generation is not available. During this period, the system usually relies on conventional sources such as coal, gas, hydro, nuclear and wind to meet demand.Peak demand figures, whether daily or monthly, are largely statistical reference points, as they reflect the highest load recorded at any moment during a given period on a particular day, often for a brief duration.On Saturday — when the peak demand surged to record high of 256 GW — there was a peak shortfall of around 4.2 GW at 10:39 PM, Grid India data shows.A day earlier, on Friday, peak demand was 240 GW at 10:34 PM, when the shortfall peaked at about 5.4 GW.Similar shortage was also witnessed during evening peak demand which is recorded at 8 PM everyday. On Friday, the evening peak demand requirements reached 233 GW, with a shortfall of around 3.9 GW. The same stood at 3.5 GW for Saturday when the evening peak demand was 235 GW.Notably, on both days, the daily peak demand was recorded during the day at around 3:45 pm, which was met without any shortage.Story continues below this adAccording to officials aware of the matter, the primary reason for the shortfall during non-solar hours was a spike in forced and partial outages. While planned outages were expected to be limited to around 3 GW on both days, forced and partial outages surged to nearly 26 GW, The Indian Express has learnt from government sources.Also in Explained | How heatwave has driven an early surge in India’s power demandAnother senior official also attributed the gap in demand and supply during non-solar hours to forced outages in coal-based power plants, which the official said stood at around 18 GW. “There was also partial outage of around 3-4 GW. So, the total outage is around 21 GW,” the official added.A planned maintenance shutdown of a generation unit is a temporary pause to perform crucial repairs, inspections, and upgrades that cannot be done while the plant is running. In contrast, forced outages are unplanned disruptions caused by technical faults, equipment failures, or fuel constraints.The high level of such outages on Friday and Saturday was largely driven by extreme heat conditions, which put additional stress on generation equipment and reduced plant availability precisely when demand was peaking late in the evening.Story continues below this adOn these two days, the country’s thermal power plants generated 184-187 GW out of installed capacity of 227 GW.Queries mailed to the Ministry of Power remain unanswered till the time of filing this report.What makes this year differentMeanwhile, spot electricity prices in the country are also witnessing sharp increases at night, reflecting the stress on the grid as scorching temperatures drive demand for power to run appliances like air conditioners. *Market clearing price (MCP) is a price at which electricity is traded. It is determined by the equilibrium of demand bids and supply offers.Data from Indian Energy Exchange (IEX), the country’s biggest power trading bourse, shows the spot price of electricity in Day Ahead Market (DAM) segment touching the maximum regulatory limit of Rs 10 per kilowatt hour (KWh) at night before declining to around Rs 1.5 per KwH during the day.Story continues below this adTraditionally, electricity demand peaks during the summer months of June-July or in early autumn (September-October), driven by widespread air-conditioner use across households and businesses. This year, however, the surge in power demand has occurred in April itself. On Monday, the India Meteorological Department (IMD) stated that gradual relief from heatwave conditions is expected from Tuesday.NewsletterFollow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.SubscribeThe last time annual peak demand was reached this early in the year was in 2022–23. The rise is also sharp on a year-on-year basis. In April 2025, peak demand stood at 235 GW, compared to 256 GW so far this month.