India is now generating so much solar power that a growing portion of it is going to waste. The reason is simple: the country's energy storage capacity has not kept pace with the rapid expansion of solar generation. Every day, enough clean electricity to meet more than a quarter of Delhi's daily power demand is being discarded because the grid lacks sufficient battery storage and flexibility to preserve surplus solar energy generated during the afternoon for use during the evening peak.
This paradox is the result of India's remarkable solar expansion. Solar energy accounted for just 2 per cent of the country's installed electricity capacity in 2015-16. By May 2026, that figure had climbed to nearly 29 per cent, helping meet rising daytime electricity demand while reducing dependence on coal. However, this rapid growth has also exposed a major challenge in India's clean energy transition.
As the world's third-largest carbon emitter and the fifth-largest economy, India has expanded renewable energy generation at an unprecedented pace. It is now producing clean electricity faster than it can store and utilise it.
The scale of this transformation was visible on July 6, when renewable sources briefly supplied half of India's electricity demand.
"India's clean power just hit a new record. At 11:46 AM on 6 July 2026, more than half of India's electricity came from clean energy sources, even as system demand hit 221 GW. Although a brief peak, this is a strong signal of where India's grid is headed," former NITI Aayog CEO Amitabh Kant wrote on X on July 7.
The challenge now is ensuring that all the renewable electricity generated can be effectively utilised. Achieving that will require significant investments in energy storage and more flexible grid management.
According to a working paper published by the Economic Advisory Council to the Prime Minister (EAC-PM), authored by EAC-PM member Sanjeev Sanyal and IRS officer Satvik Dev, India is routinely curtailing enough solar power to supply a major city—not because demand is lacking, but because there is insufficient storage to absorb the excess generation.
The paper argues that India's electricity challenge has fundamentally changed. The key question is no longer whether the country can generate enough electricity, but whether it can deliver solar power when consumers actually need it.
WHY THE TIMING GAP BETWEEN SOLAR AND CONVENTIONAL POWER IS COSTING INDIA
Using electricity generation data recorded every 15 minutes, the EAC-PM study finds that India's power grid is increasingly experiencing what is known as the "duck curve."
During the day, abundant solar generation meets a significant share of electricity demand. However, once the sun sets and solar output rapidly declines, demand remains high, forcing coal, hydro and gas plants to sharply increase generation to fill the gap.
Solar power enjoys "must-run" status under India's Electricity Rules, 2021, meaning it is dispatched before conventional power sources.
As solar generation rises each morning, coal and gas plants are compelled to reduce output significantly. By late afternoon, however, solar production begins falling just as household electricity demand starts increasing, requiring conventional generators to ramp up output at an unusually rapid pace.
MORE SOLAR POWER, YET GREATER DEPENDENCE ON CONVENTIONAL GENERATION
The EAC-PM paper notes that this daily transition has become considerably steeper over the past three years.
Comparing average summer days in May 2023, May 2025 and May 2026, the morning reduction in conventional generation from coal, oil and natural gas nearly tripled—from around 18 gigawatts (GW) in May 2023 to almost 53 GW in May 2026—as solar output surged.
For perspective, one gigawatt equals one billion watts and can power approximately one crore (10 million) 100-watt light bulbs simultaneously.
The evening ramp-up has also intensified, rising from roughly 36 GW in May 2023 to nearly 74 GW in May 2026.
According to the study, conventional power plants are increasingly being required to swing rapidly between periods of oversupply during the day and shortages after sunset, despite India's record levels of solar generation.
SURPLUS SOLAR POWER IS BEING WASTED
The EAC-PM estimates that India curtailed approximately 747 gigawatt-hours (GWh) of solar electricity during May 2026 alone.
On an average day, around 24 GWh of solar power had to be curtailed because the electricity grid was unable to absorb the excess generation or because ancillary market mechanisms required output reductions to maintain grid stability.
To put the figure into perspective, 747 GWh is enough electricity to keep one crore 100-watt bulbs illuminated continuously for nearly 75 hours.
The study also notes that Delhi consumes approximately 90 GWh of electricity each day. This means India is wasting enough solar electricity every day to power more than one-quarter of the national capital's daily consumption, only to face electricity shortages later the same evening.
The mismatch becomes even clearer when examining grid shortages.
Across April and May 2026, electricity shortages during daylight hours occurred on only six of 61 days. By contrast, shortages during evening and nighttime peak demand were recorded on 36 of those 61 days, with deficits exceeding five gigawatts on certain occasions.
According to the report, the issue is not inadequate electricity generation but the inability to shift surplus daytime solar energy to evening hours when demand is highest.
ENERGY STORAGE EMERGES AS THE MISSING LINK
The EAC-PM paper argues that energy storage has become the most critical missing component in India's clean energy transition.
The authors estimate that meeting even half of a typical summer evening demand surge would require around 130 GWh of stored electricity to be discharged between 1 pm and 8 pm.
However, India's entire battery and pumped-storage network currently delivers only around 23.8 GWh on an average day.
Although pumped-storage capacity has nearly reached targets outlined under the National Electricity Plan, battery deployment remains significantly behind schedule.
Against a projected grid-scale battery capacity of 8.68 GW for 2026-27, only 0.27 GW had been installed by January 2026. While recent additions have increased installed battery capacity to approximately 2.7 GW, the study says a substantial gap still remains.
The issue is already becoming visible on the ground.
According to Mumbai-based solar industry publication SolarQuarter, around 47 lakh units of solar electricity were wasted at Rajasthan's Bhadla Solar Park during the first half of April alone.
Between April 9 and April 15, generation had to be curtailed by between 15 per cent and 64 per cent on several days because the electricity grid was unable to accommodate the surplus supply, resulting in financial losses for solar developers.
Speaking to Rajasthan Patrika, Rajasthan Minister of State for Energy Heeralal Nagar said, "Solar energy is Rajasthan's strength. We are soon implementing a battery system, so that there shall be no need to stop energy production."
"For storage, we have started setting up 6,000 MW batteries," he added.
Without rapid expansion of storage infrastructure, the report warns, India's growing solar capacity could unintentionally place greater stress on the electricity grid.
Every additional solar installation increases the surplus generated during the day without solving the challenge of meeting evening demand. Meanwhile, coal-fired power stations must repeatedly reduce and increase output, raising operating costs, lowering efficiency and accelerating wear on power generation equipment.
THE NEXT PHASE OF INDIA'S SOLAR TRANSITION
The study points to California as an example of how battery storage can help overcome this challenge.
There, large-scale battery systems store surplus solar electricity during the day and release it during evening demand peaks, easing pressure on conventional generators and flattening the net demand curve.
The paper argues that India will increasingly require similar storage capabilities as its renewable energy capacity continues to grow.
Recognising this challenge, the government has already begun revising the regulatory framework.
The draft Electricity (Amendment) Bill, 2025, and the draft Electricity (Rights of Consumers) Amendment Rules, 2026 propose formally recognising energy storage systems within the electricity sector, strengthening electricity markets, enhancing non-fossil fuel purchase obligations, promoting demand-response mechanisms and introducing mandatory time-of-day electricity tariffs.
Together, these reforms aim to encourage storing inexpensive daytime electricity for use during evening peak demand.
The EAC-PM paper concludes that the next phase of India's energy transition will not be defined simply by how many gigawatts of solar capacity the country installs. Instead, its success will depend on whether electricity generated during the afternoon can still be supplied after sunset.
Until that challenge is addressed, India's solar transformation will remain incomplete. The country may continue setting new records in clean energy generation, but an increasing share of that electricity will continue to be wasted because it cannot yet store the afternoon's sunshine for use when consumers need it most.
