New Delhi: India curtailed 8,133 gigawatt-hours (GWh) of solar power — more than 8.13 billion units (kWh) of electricity — during April, May and June, the government told the Rajya Sabha on July 28. The period covered the same quarter in which India experienced unforgiving heat causing the peak power demand to hit an all-time high of 270.8 GW, on May 21.
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The curtailment was 2,417 GWh in April, 3,235 GWh in May and 2,481 GWh in June, about 2.42 billion, 3.24 billion and 2.48 billion units, respectively. Minister of State for New and Renewable Energy and Power Shripad Yesso Naik gave the figures in a written reply, citing data from Grid Controller of India Ltd.
Naik said solar power curtailment and restriction were being carried out "to maintain grid security and due to mismatch between commissioning of transmission lines and RE projects." Renewable energy curtailment, he said, "is implemented for reliable and secure operation of the grid."
The reply was to a question from Congress member Pramod Tiwari, who had asked whether the country was witnessing large-scale curtailment of solar power "as the grid struggles to absorb excess supply during the daytime."
The losses ran through a quarter of successive demand records. India's peak power demand first touched 256.1 GW on April 25 before reaching 270.8 GW on May 21, both all-time highs when they were set, according to the Ministry of Power. Renewable energy, including hydro, met about 34 percent of the May 21 peak.
Both records were set in the afternoon — 3:38 pm on April 25 and between 2 pm and 5 pm on May 21 — within solar generating hours. But the curtailed output was largely stranded in transmission-constrained pockets of Rajasthan and Gujarat, unable to reach demand centres elsewhere, so it did not offset the peaks one-for-one.
Independent assessments point to a widening gap between renewable capacity and the grid's ability to evacuate it. Rating agency ICRA said in July that about 33 percent of 54.8 GW of recently commissioned renewable capacity was being evacuated through the temporary general network access (T-GNA) route as of May, with curtailment during solar hours running at 50 to 60 percent. It said solar curtailment was most pronounced in Rajasthan and Gujarat and limited in the south.
In Rajasthan, the country's largest solar state, about 4 GW of capacity has been stranded, with the Rajasthan Solar Association estimating losses of up to Rs 250 crore. Analysis by think-tank Ember estimated total renewable curtailment of about 470 GWh in the December-March quarter, of which roughly 300 GWh was due to transmission constraints, equivalent to 1.5 to 2 percent of potential generation in the northern and western regions.
ICRA said only 12 percent of transmission projects awarded through competitive bidding and commissioned by March were completed on schedule, with a median delay of more than 10 months, and estimated the sector would need Rs 5 lakh crore to Rs 6 lakh crore of investment between 2026 and 2032. Persistent curtailment, analysts have warned, could weigh on India's target of 500 GW of non-fossil capacity by 2030.
Naik listed measures to ease evacuation. These include the CERC General Network Access Regulations, in force since October 2023, and interim arrangements using "available transmission margins, including through Temporary General Network Access (T-GNA), to facilitate evacuation of generation capacity until the planned transmission systems are commissioned." He also cited the Central Electricity Authority's 2023 regulations on flexible operation of coal-based thermal units, and monitoring of generation and transmission projects by the Central Transmission Utility through Joint Coordination Committee meetings.
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Analysts have flagged battery storage as a near-term fix; Ember has estimated that 3 GW to 4 GW of two-hour battery storage could absorb most of the curtailed renewable energy.