Why India curtailed solar energy during peak summer power demand

India recorded an all-time peak power demand of 256 GW on 26 April 2026, driven by summer heat waves and rising air-conditioning loads. Despite record demand...

What Happened

India recorded an all-time peak power demand of 256 GW on 26 April 2026, driven by summer heat waves and rising air-conditioning loads.
Despite record demand, the country simultaneously curtailed significant amounts of solar and wind power — approximately 27 GW (72 MU) of solar and 4 GW (6 MU) of wind were curtailed during Q4 2025–26.
An additional 83 GW (103 MU) of solar and 11 GW (17.5 MU) of wind were curtailed under India's Tertiary Reserve Ancillary Services (TRAS) mechanism, a manually activated grid balancing tool used to manage congestion.
Gujarat recorded the highest curtailment levels, reflecting grid integration stress in states with the highest renewable penetration.
The primary driver of mid-day curtailment was the inflexibility of coal thermal plants, whose load factor at noon approached the mandated Minimum Thermal Load (MTL) of 55%, preventing further reduction to absorb surplus solar.
Around 50 GW of renewable energy capacity remains stranded across India due to transmission infrastructure bottlenecks.

Static Topic Bridges

India's Renewable Energy Targets and NDC Commitments

India committed at COP26 (Glasgow, 2021) to achieve 500 GW of non-fossil fuel electricity capacity by 2030 and to meet 50% of cumulative electric power installed capacity from non-fossil fuel sources. These targets form part of India's Nationally Determined Contributions (NDCs) under the Paris Agreement. Solar energy is expected to contribute nearly 300 GW of the 500 GW target.

India's total renewable energy installed capacity reached approximately 258 GW by December 2025.
Solar installed capacity reached 132.85 GW as of November 2025, a 41% year-on-year increase.
India achieved the milestone of 50% non-fossil power capacity share in early 2026, ahead of the 2030 NDC target.
The government approved plans to add 50 GW of renewable capacity annually for five consecutive years to meet the 500 GW goal.

Connection to this news: The curtailment episode reveals the paradox at the core of India's energy transition: capacity addition has outpaced grid flexibility and transmission expansion. Achieving 500 GW of renewable capacity without commensurate investment in storage and transmission will increase curtailment, raise consumer tariffs, and reduce returns for renewable energy investors — creating a structural headwind to the very targets India has pledged.

Grid Flexibility and Battery Energy Storage Systems (BESS)

Grid flexibility refers to the power system's ability to rapidly match supply with demand as the generation mix shifts from dispatchable (coal, hydro) to variable (solar, wind) sources. Battery Energy Storage Systems (BESS) store excess renewable generation and discharge during evening peak hours when solar output falls, smoothing the demand curve and reducing curtailment.

The Ministry of Power directed all future solar tenders to mandatorily include two-hour co-located storage equivalent to 10% of installed capacity — targeting approximately 14 GW/28 GWh of BESS by 2030.
New solar and wind projects procured by distribution licensees must include storage sized to at least 50% of renewable capacity, with a minimum duration of 2 hours up to FY 2029–30, rising to 4 hours from FY 2030–31.
Viability Gap Funding (VGF) support for BESS was approved by the government in 2025 to de-risk early projects.
Coal plants' mandated Minimum Thermal Load (MTL) of 55% means they cannot ramp down sufficiently during peak solar hours — a structural inflexibility that makes BESS deployment urgent.
The Central Electricity Authority (CEA) issued amended technical standards in 2026 requiring large BESS projects (50 MW+) to have black-start capability and grid-forming inverter technology.

Connection to this news: The April 2026 curtailment event is a direct consequence of inadequate BESS deployment relative to solar capacity. The policy mandate for co-located storage in new tenders directly addresses this gap, but the existing fleet of solar plants without storage continues to face curtailment, representing stranded investment and lost clean energy.

Transmission Infrastructure and the Green Energy Corridor

Renewable energy generation is geographically concentrated — solar in Rajasthan, Gujarat, and Andhra Pradesh; wind in Tamil Nadu, Gujarat, and Karnataka — while demand centres are elsewhere. The Green Energy Corridor (GEC) is the national programme to build dedicated high-voltage transmission lines to evacuate renewable power to load centres.

Approximately 50 GW of renewable energy capacity was stranded due to transmission bottlenecks as of 2026.
Green Energy Corridor Phase I (2015–2022) built approximately 9,700 circuit kilometres of new transmission lines and 22,600 MVA of substation capacity.
Green Energy Corridor Phase II (approved 2022) targets 10,750 circuit kilometres of additional lines to connect renewable-rich states.
Tertiary Reserve Ancillary Services (TRAS) is a manually activated mechanism to curtail generation and manage grid congestion when automatic systems are insufficient.
Gujarat's high curtailment reflects that its renewable penetration has exceeded the local grid's absorption capacity even though overall national demand was at a record.

Connection to this news: The 50 GW of stranded capacity and Gujarat's curtailment demonstrate that transmission expansion under the Green Energy Corridor has not kept pace with renewable capacity addition. The simultaneous occurrence of record national demand and regional curtailment is a transmission planning failure — power that could not physically travel to where it was needed.

Key Facts & Data

India's all-time peak power demand: 256 GW (26 April 2026).
Solar curtailment in Q4 2025–26: ~27 GW (72 MU); wind: ~4 GW (6 MU).
Additional TRAS-linked curtailment: 83 GW-equivalent solar (103 MU); wind 11 GW (17.5 MU).
India's renewable installed capacity: ~258 GW (December 2025); solar: 132.85 GW (November 2025).
500 GW non-fossil target by 2030 (COP26/NDC commitment); solar to contribute ~300 GW.
~50 GW of renewable capacity stranded due to transmission constraints.
Coal Minimum Thermal Load (MTL): 55% — the inflexibility floor preventing mid-day coal ramp-down.
BESS mandate: 2-hour storage at 10% of solar capacity for new tenders; VGF support approved 2025.
Gujarat recorded highest state-level curtailment in the reporting quarter.