India Curtailed Nearly 11 TWh of Solar Power Over 15 Months

Insufficient transmission and storage capacity limit clean energy use

BENGALURU, India — India curtailed nearly 11 terawatt-hours of solar generation over the past 15 months, enough electricity to power roughly 10 million homes, even as extreme summer heat pushed the country’s power demand to new highs.

The figure, drawn from government data and analysis by the energy think tank Ember, captures solar generation that was available but never reached consumers. The curtailment occurred during a period when power demand surged at the height of summer and the country struggled to meet evening needs as air conditioners ran longer amid hotter nights.

Despite that demand, some renewable energy providers were instructed to limit their output because India’s grid was holding more clean electricity than it could safely handle. The constraints operated alongside — not in place of — the heat-driven consumption spike, producing the apparent paradox of renewable generators being told to throttle back while air-conditioning loads surged.

India is the world’s most populous country and one of the largest emitters of climate-polluting gases, and it is rapidly adding clean energy, especially solar, to its power mix. The pace of solar installation has grown faster than the infrastructure needed to transport and store that electricity.

Three constraints keep the country from using all the clean power it can generate: insufficient transmission capacity to move solar electricity from where it is produced to where it is consumed; limited storage capacity to save daytime output for evening use; and the technical difficulty of shifting the grid’s mix between fossil-fueled and renewable sources in real time.

The mismatch is visible in daily operating patterns. When solar output peaks during daylight hours, the grid cannot always move that electricity to demand centers or hold it for later use. As evening approaches and air-conditioning load rises, the solar contribution falls just as the need for power reaches its daily high.

Poor monsoon rains compounded the strain. The shortfall in seasonal rainfall drove additional demand for electricity to pump groundwater for agriculture, adding to the cooling-driven urban load at the same time that solar curtailment was highest.

The pace of solar installation has outpaced the build-out of transmission lines and storage facilities needed to absorb the new supply. The 11-terawatt-hour curtailment figure is the concrete measure of that gap — solar power that was generated, demand that existed, and a grid that could not bridge the two.