Grid Constraints Curtailed 119 GW of Renewables in India in September

Curtailing renewable power means reducing or stopping electricity from solar and wind plants even when those plants could generate it. Operators do this when the grid cannot safely absorb, move, or balance all the available electricity. It matters because clean energy is lost despite investment in generation capacity.

In September, India had 118.6 GW of renewable capacity affected by curtailment. Solar made up 96.9 GW, while wind accounted for 21.7 GW. The main pressures were mismatches between demand and generation, transmission constraints, limited storage, and insufficient grid flexibility.

The curtailed energy equaled 1.28% of India’s total renewable generation for the month. This shows that India is adding solar and wind faster than its networks and storage systems can manage them. The country plans to require battery storage at new solar and wind projects from July 2027.

India’s September curtailment affected 118.6 GW of renewable energy capacity. That figure describes the solar and wind capacity affected by grid restrictions, rather than a direct measure of electricity produced and lost. The scale matters because it reveals a growing gap between renewable expansion and the systems needed to use it.

Solar was responsible for 96.9 GW of affected capacity. Wind accounted for 21.7 GW. Combined, those figures equal 118.6 GW. Grid-India data reported the capacity figures, while JMK Research & Analytics identified demand mismatches, transmission limits, limited storage, and weak flexibility as key causes.

The curtailed renewable energy represented 1.28% of India’s total renewable generation in September. That percentage is smaller than the capacity figure might suggest because capacity and actual energy generation are different measures. Still, the result shows that infrastructure constraints are already affecting clean-power delivery.

Renewable curtailment and power shortages can happen at the same time because electricity must be available in the right place and at the right moment. Power that cannot travel through constrained lines or be stored for later cannot solve a shortage elsewhere. The article identifies this mismatch as a central problem.

India’s curtailment was driven by demand-generation mismatches, transmission constraints, limited storage, and inadequate grid flexibility. Seasonal conditions also mattered. Renewable output could be high when demand was moderate, while other locations or later periods needed more electricity. Solar and wind generation therefore did not always match the grid’s needs.

The contradiction became visible in July and August. India recorded renewable and solar-generation records, yet more than 4% of solar power generated during those months was curtailed. At the same time, demand rose between July and September, and coal plants operated with critically low inventories. The system had energy, but not always usable energy where needed.

Adding solar capacity increases the amount of electricity India can produce, but it also increases the need for transmission, storage, and flexible grid operations. If those supporting systems lag behind, more renewable electricity must be reduced during periods when the network cannot absorb it.

Between May and August, India added 44.6 GW of new solar capacity. JMK Research & Analytics linked that rapid expansion to pressure on transmission infrastructure and grid flexibility. The issue was not simply the amount of solar installed. It was whether the electricity could be moved, balanced, or stored when generation rose.

Curtailments surged fourfold compared with the previous year during that period. The increase shows how fast construction can expose network bottlenecks. India’s growing renewable fleet therefore needs matching investment in grids, transmission, storage, and flexibility. Without that support, additional solar capacity can produce less usable clean electricity than its headline capacity suggests.

Transmission networks and storage connect renewable supply with the moments and places where electricity is needed. When they cannot keep up, operators reduce available solar and wind generation. This wastes potential clean output and leaves the system more dependent on other power sources during periods of higher demand.

The article shows this problem clearly. India curtailed 118.6 GW of renewable capacity in September, while more than 4% of solar generation was curtailed in July and August. Yet India also experienced power availability shortages. These events show that installed capacity does not automatically guarantee deliverable electricity.

Reliability can weaken when the grid lacks flexibility, because supply cannot respond smoothly to changing demand or variable renewable output. Costs may also rise when systems need more backup, transmission upgrades, or storage, although the article gives no cost estimate. India plans to require batteries at solar and wind sites from July 2027 to reduce these pressures.

Storage reduces curtailment by separating the time of generation from the time of use. When solar or wind output exceeds immediate demand or available network capacity, a battery can store the excess instead of forcing operators to reduce generation. Later, it can release electricity when demand is higher.

For example, strong daytime solar production may coincide with moderate demand. A battery at or near the project can charge during that surplus period. When demand increases after solar output falls, the battery can discharge power. This helps balance supply and demand and can reduce the need to send all electricity through constrained lines at once.

The article identifies limited storage as a key reason for curtailment. India plans to require developers of solar and wind projects to install battery storage at project sites from July 2027. The source does not specify the battery capacity or quantify how much curtailment the rule will prevent.

An electricity grid must balance generation with demand continuously. If supply exceeds what users need, electricity can be wasted or the system can face operating problems. If supply falls short, power availability shortages can result. Reliable operation therefore depends on matching usable generation with consumption across the network.

Solar and wind are variable sources because their output changes with sunlight and wind conditions. Their production may also be highest when demand is moderate. The article describes seasonal overlaps between high renewable output and moderate demand, along with demand-generation mismatches. Without flexibility, the grid may need to curtail available renewable power.

Transmission, storage, and flexible operations help manage these changes. Transmission moves electricity to other demand areas, while batteries shift it to later periods. India’s curtailment figures show the consequences of insufficient support: 118.6 GW of renewable capacity was affected in September, even as demand later surged and shortages occurred.