In Short : India curtailed around 2.3 TWh of solar power between May and December 2025 to ensure grid stability, according to Ember. High daytime solar generation, limited operational flexibility of coal-fired plants, and lower-than-expected demand during some months forced grid operators to reduce renewable output, highlighting the urgent need for storage and flexibility solutions.
In Detail : India’s power sector faced notable solar energy curtailment between May and December 2025, with approximately 2.3 TWh of generation reduced to maintain grid stability. The curtailment occurred during periods of high solar output when the grid struggled to balance supply and demand safely.
The rapid expansion of solar capacity has significantly increased midday electricity generation across the country. While this growth supports India’s clean energy targets, it also creates operational challenges when renewable output exceeds immediate consumption needs.
A major contributor to the curtailment was the limited flexibility of coal-based power plants. Many thermal units were already operating close to their minimum technical limits, restricting their ability to ramp down further when solar generation peaked.
Electricity demand trends also played an important role. During certain months, milder weather conditions reduced overall power consumption, widening the gap between available solar generation and system demand.
To avoid grid instability, including frequency and voltage fluctuations, system operators were required to curtail solar output during specific hours. These measures were taken as precautionary steps to protect the reliability of the national grid.
The curtailed solar energy represented lost potential to displace fossil fuel-based generation. This not only had economic implications for renewable generators but also limited the environmental benefits associated with higher clean energy utilisation.
The situation underscored the growing importance of energy storage technologies. Battery storage can absorb excess solar generation during the day and release power during evening peak hours, helping reduce the need for curtailment.
In addition to storage, demand-side measures such as time-of-day tariffs and demand response programs can help align electricity consumption with periods of high renewable generation, improving overall system efficiency.
Overall, the solar curtailment episode highlights a transitional challenge in India’s energy journey. Continued investment in grid flexibility, storage infrastructure, and market reforms will be essential to support rising renewable capacity while maintaining a stable and reliable power system.
