- Gujarat, Rajasthan account for 79% of curtailment
- Storage, grid flexibility could improve usable supply
India curtailed 378.52 MU of renewable electricity during September 2026, even as coal-fired generation increased sharply and power plants drew down fuel inventories.
The combination highlights a challenge that additional generating capacity alone cannot resolve: electricity must be available at the right time and location.
September’s curtailed energy was relatively small nationally, but its concentration in renewable-rich states-and the predominance of system-balancing instructions shows why transmission, storage and flexible operation are becoming increasingly important.
Curtailment falls, but integration pressures remain
A Grid-India-based analysis records September curtailment equivalent to 1.28% of reported renewable generation. Curtailment declined 43.3% from August and approximately 24% year-on-year.
However, this improvement followed much higher losses earlier in the year. July curtailment reached 1,166.52 MU.
September’s decline therefore provides relief, but does not by itself establish that underlying integration constraints have been resolved.
The headline capacity figures also require care. The reported 96.9 GW of solar and 21.7 GW of wind represent sums of daily curtailed-capacity observations across the month. They are neither simultaneous unavailable capacity nor necessarily distinct generating capacity. The same installation can appear on multiple days.
The meaningful measure of electricity lost during September is 378.52 MU.
Emergency Tertiary Reserve Ancillary Services (TRAS) Down accounted for more curtailment than the real-time system-constraint category. This can be interpreted as evidence that balancing supply and demand was a larger immediate trigger than congestion alone.
That distinction matters. Transmission investment can address evacuation bottlenecks, but cannot independently resolve every mismatch between generation and demand. Storage, flexible generation, forecasting and demand shifting address different parts of the problem.
High demand can coexist with local renewable surpluses
India’s September electricity generation increased 11.1% year-on-year to 173,962 MU. Coal generation rose 13.6% to 112,840 MU, while hydro declined approximately 20%.
Coal supplied around 78% of the net increase in generation.
Yet high national demand does not guarantee that every available renewable unit can be accommodated. A local network can face operating limits, or available generation can exceed what the system can absorb during particular periods.
The reverse can occur after sunset, when solar output disappears and dispatchable supply becomes more valuable.
Our early-October monitoring showed non-solar shortages exceeding 5 GW on some days, alongside repeated high exchange prices. These observations concern a different period from September’s curtailment but illustrate the same planning challenge: monthly energy availability and hourly supply adequacy are different measures.
Concentration points towards targeted solutions
Gujarat and Rajasthan accounted for approximately 79% of September’s curtailed energy.
Rajasthan’s reported curtailment was entirely solar. Gujarat contributed approximately two-thirds of curtailed wind energy, alongside substantial solar losses.
This concentration suggests that the location of investment matters as much as its scale. Storage or transmission added elsewhere may provide limited relief to a repeatedly constrained renewable node.
Targeted measures could include batteries near affected projects, stronger evacuation infrastructure and industrial demand shifted towards periods of recurring renewable surplus.
Storage offers potential, but the arithmetic has limits
September’s curtailed energy averaged approximately 12.62 GWh/day. This is equivalent to around 3.15 GW discharged for four hours, before accounting for losses and operating constraints.
That is an illustrative energy comparison, not a battery-sizing recommendation.
Curtailment varies between days and locations. Batteries need sufficient charging access, suitable connection capacity and an economic reason to operate when the system requires them.
Nor does curtailed electricity in one region automatically become deliverable during an evening shortage elsewhere. Network conditions remain important.
Implications for coal and industrial consumers
Power plants consumed approximately 78.64 mnt of coal during September against receipts of 70.79 mnt, drawing heavily on inventories.
Recovering renewable energy could reduce some thermal generation and fuel consumption. However, September’s curtailed electricity represented only about 0.22% of total national generation. Eliminating it would not have resolved the wider coal-stock deficit.
The greater benefit is cumulative: improving renewable utilisation while preserving dependable supply during difficult hours.
For industrial consumers, flexible production schedules may help absorb cheaper electricity when available. Processes that cannot shift demand still require reliable supply and protection against expensive peak-hour procurement.
BigMint assessment
India’s experience supports a broader measure of power-sector progress: usable electricity delivered when and where consumers need it.
Renewable additions, thermal availability and coal deliveries remain important. Their value increases when accompanied by transmission, storage and operating flexibility.
September’s curtailment was manageable in national volume terms, but its geographic concentration provides a clear signal for targeted investment. Addressing these constraints can improve renewable revenues, reduce avoidable fuel use and strengthen supply reliability.
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