Renewable Energy Curtailment Impacts 118.6 GW Capacity in India in September 2026

Renewable energy curtailment affected a cumulative 118.6 gigawatts (GW) of renewable capacity in India in September 2026, according to data from JMK Research & Analytics. The affected capacity comprised 96.9 GW of solar and 21.7 GW of wind capacity. During the month, 378.52 million units (MU) of variable renewable energy were curtailed, representing 1.28 per cent of India's total renewable generation.

The findings point to ongoing grid integration challenges across the power sector. Key reasons cited for the curtailment include demand-generation mismatches, transmission constraints, limited battery energy storage system (BESS) capacity, grid flexibility issues, and seasonal overlaps between high renewable output and moderate demand.

Curtailment rose sharply between May and August 2026, reaching nearly four times the levels recorded during the same period in 2025. JMK Research noted that the addition of approximately 44.6 GW of solar capacity in FY26 has increased pressure on transmission infrastructure and grid flexibility. While curtailment declined by 43.31 per cent month-on-month in September compared to August, researchers explained that this reduction offers seasonal relief rather than proof of structural improvement in grid integration.

Solar power accounted for 83 per cent of September curtailment at around 314 MU. Meanwhile, wind curtailment nearly tripled year-on-year to 64.98 MU, increasing its share of total curtailment from 4.7 per cent to 17 per cent. On a monthly timeline, curtailment remained below 50 MU per month between December 2025 and February 2026, before rising from April onwards and peaking at 1,166.52 MU in July.

An analysis of the September figures shows that 146.73 MUs (39 per cent) were curtailed due to real-time system constraints, while 231.79 MUs (61 per cent) resulted from Emergency TRAS Down in variable renewable energy. Real-time constraints involve back-down instructions issued to manage congestion and operating limits, whereas Emergency TRAS Down involves reducing generation to balance supply and demand. The use of TRAS Down indicates limited flexibility in the power system to absorb available renewable output.

Geographically, curtailment was heavily concentrated in two states. Gujarat (187.76 MU, 49.6 per cent) and Rajasthan (110 MU, 29.1 per cent) together accounted for roughly 79 per cent of total curtailment. Gujarat contributed about two-thirds of the wind curtailment at 43.75 MU, while Rajasthan's curtailment was entirely solar. Karnataka and Tamil Nadu also recorded regional variations, with solar dominating in Karnataka and wind contributing a larger share in Tamil Nadu.

To address these integration hurdles, JMK Research noted that battery energy storage systems could reduce curtailment by storing midday surplus energy and discharging it during evening peaks. The September curtailment figures translate to an average of 12.6 gigawatt-hours (GWh) per day, or roughly 3 GW of four-hour storage capacity. Prioritising constrained nodes in Gujarat and Rajasthan with appropriate storage sizing could help absorb emergency downward reserves events.

"The data from JMK Research highlights critical infrastructure bottlenecks that accompany rapid capacity additions in the renewable energy sector. As solar and wind installations scale up, addressing transmission constraints and deploying adequate battery energy storage systems are essential for grid stability. Managing regional concentration in states like Gujarat and Rajasthan will be vital for optimizing power evacuation and ensuring long-term efficiency for energy developers and utilities." — Dr. Shishir Gupta, Founder & CEO, StartupLanes