India Curtailed 2.3 TWh Solar in 2025 as Grid Flexibility Lags

India curtailed 2.3 terawatt-hours of solar power between May and December 2025, enough to supply nearly 400,000 homes for a year, as grid flexibility failed to keep pace with record renewable additions, according to energy think tank Ember. Transmission bottlenecks, coal plant inflexibility, and inadequate storage are identified as structural constraints threatening India's 500 GW non-fossil capacity target by 2030.

India added a record 38 GW of solar capacity in 2025, lifting non-fossil fuel sources to 50 per cent of installed power capacity. Yet coal plants operating above a minimum technical load of 55 per cent could not ramp down during peak solar hours, forcing output curtailment. At least 30 solar and wind projects faced curtailment between March and August 2025, with developer losses estimated at up to Rs 700 crore. Some projects in Rajasthan, Gujarat, Maharashtra and Tamil Nadu received only temporary network access, with grid operators instructing curtailment of up to 48 per cent of daily generation during constrained periods.

Central Electricity Authority chairperson Ghanshyam Prasad acknowledged at the India Energy Transition Summit that renewable capacity is expanding faster than the system can absorb, creating localised curtailment in high-renewable states including Rajasthan and Gujarat. Financial institutions are monitoring curtailment risks as a factor in investment confidence for large-scale renewable deployment. A CRISIL-FICCI report identified battery energy storage systems, pumped hydro storage, and thermal energy storage as essential enablers for a reliable power supply and supports the 500 GW renewable target.

Policymakers are planning approximately 100 GW of pumped hydro storage within the next decade as the preferred large-scale balancing solution. Transmission project timelines may need to extend from roughly two years to as much as three years to reflect right-of-way and execution challenges. Hyperscale data centres, requiring dual supply sources from the outset, are adding complexity to grid planning. The CEA is pursuing potential-based transmission planning to align infrastructure with renewable growth, but experts warn that without urgent action on storage deployment and system flexibility, curtailment could undermine India's clean energy investment environment.

Key figure — 2.3 TWh of solar power curtailed between May and December 2025