Renewable Curtailment Reaches 23 GW Amid Coal Flexibility Limits

GRID-India told the Central Electricity Authority committee that rising renewable capacity is intensifying the duck curve, with surplus mid-day solar and an evening ramp of nearly 60 GW creating operational strain. Data show peak renewable curtailment of 23 GW between May and November, with significant events on 12 October and nine November. Intra-state thermal units unable to operate at 55 per cent technical minimum load were identified as a key constraint.

GRID-India warned of grid security risks after reporting that in May system frequency remained above the Indian Electricity Grid Code operating band for nearly 20 per cent of the time and that high frequency persisted for almost four hours during solar generation. The permissible band covers 49.900 Hz to 50.050 Hz and excursions beyond that range raise the risk of unstable conditions and equipment stress. Operators have used emergency down dispatch and thermal backing down but challenges persist during peak solar output.

The committee recorded that on 25 May 2025, despite backing down the national thermal fleet to approximately 58 per cent and curtailing nearly 10 GW of solar through TRAS emergency down dispatch, system frequency rose to 50.48 Hz. The data list curtailment above 16 GW on nine November, above 13 GW on 28 September and one June, above 11 GW on 31 May and 10 August, and a minimum of four point six GW on 29 July. Stakeholders are assessing operational and market measures to reduce avoidable curtailment.

As India pursues a target of 500 GW of non-fossil fuel capacity and 50 per cent non-fossil installed capacity by 2030, the CEA has proposed a phased roadmap to enable coal-fired plants to operate at 40 per cent minimum technical load by 2030. The plan includes two-shift thermal operations, battery energy storage systems and expansion of pumped storage projects. GRID-India told the committee that technical progress on 55 per cent Technical Minimum Load among inter-state stations is being limited by commercial and regulatory factors, and that structural reforms will be required alongside technical measures.

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