Renewable Curtailment in India: 470 GWh in Q1 2026

Why curtailment is becoming a frontline problem

India’s renewable build-out is moving faster than the grid that must carry that power to consumers. Recent reports point to a widening gap between new solar and wind capacity and the transmission, evacuation, and balancing systems needed to absorb it. Curtailment, in this context, is not just a technical grid action. It translates into clean electricity that is generated but not delivered, which means idle assets and weaker returns for developers. It also slows the effective pace of decarbonisation, because lost renewable output must be replaced by other sources.

The scale of the issue is now visible in reported data from multiple sources cited in the text. India’s curtailment in Q1 2026 was estimated at around 470 GWh, with nearly 300 GWh attributed directly to transmission constraints. That framing matters because it links the problem to infrastructure and planning, rather than to a shortage of renewable investment.

What the latest numbers show

Curtailment volumes are rising alongside renewable penetration, and the reported impacts are concentrated at regional pooling stations and high-renewable states. A cited Ember analysis indicates that transmission constraints caused losses during Q1 2026, with Northern and Western regions particularly affected. One day stands out in the reporting: March 30, 2026 recorded a loss of 34 GWh of clean generation, described as roughly equal to the daily electricity consumption of about 5 million urban middle-class households.

Separate reporting cited in the text also points to solar curtailment at scale in 2025. IEEFA reported that India curtailed approximately 2.3 TWh of solar output in 2025 due to grid security concerns, with curtailment rising as renewable penetration increased. Another Ember-cited figure in the text notes 2.3 TWh of solar curtailed between May and December, driven by weak daytime demand, forecasting errors, and limited flexibility in the coal fleet, with nearly 0.9 TWh lost in October alone.

The structural gap: generation is faster than evacuation

The underlying problem described is a lack of synchronised planning across generation, transmission, and storage. Renewable projects can be commissioned faster than transmission corridors, creating periods where capacity exists on paper but the grid is not ready to evacuate output. The text describes this as a core planning mismatch rather than a slowdown in renewable investment itself.

The issue becomes sharper when flexibility is limited. Without enough storage or other balancing tools, grid operators have fewer options during periods of strong midday solar output or sudden wind ramps. In such situations, operators may curtail renewables to protect grid security and frequency, especially if other power sources are already at operational limits.

CERC connectivity data and signs of stranded capacity

CERC data cited in the text flags underutilisation and bottlenecks. It states that 31.8 GW of allocated transmission connectivity is currently underutilised due to project delays and evacuation bottlenecks. More critically, over 50 GW of renewable energy capacity is described as either stranded or operating under evacuation constraints.

The operational pinch is reported to be acute in renewable-rich states such as Rajasthan and Gujarat. The text links the stress to grid congestion, delayed evacuation approvals, and recurring curtailment events. It also notes that key 220 kV and 400 kV transmission corridors are increasingly congested, contributing to lower plant utilisation factors and rising pressure on project revenue.

Why curtailment happens: five grid-level triggers

The text outlines a set of interlinked reasons renewable generators are asked to back down even when they can produce more:

1. Transmission congestion where lines are already heavily loaded.
2. Insufficient evacuation structure in remote, renewable-rich locations with inadequate substations or missing high-voltage lines at injection points.
3. Grid balancing and frequency management challenges as variable solar and wind increase the real-time balancing burden.
4. Weak-grid conditions including voltage fluctuations and frequency deviations.
5. Delayed transmission approvals and coordination involving PGCIL, SLDCs, and inter-agency clearances.

This list is important because it shows curtailment is rarely driven by a single fault. It is often the combined outcome of congestion, delayed readiness, and limited operational flexibility.

Company lens: ReNew Energy flags lost solar output

The text highlights that the issue is not limited to system-wide statistics. ReNew Energy Global Plc is cited as being forced to scale back solar generation due to grid bottlenecks. ReNew’s leadership attributes frequent directives to reduce output during peak solar hours, especially around midday, to insufficient transmission infrastructure.

The reported impact is meaningful at the company level. ReNew, described as accounting for about 5 percent of India’s 223 GW renewable energy capacity, has said that as much as 15 percent of its daily solar output is wasted on certain days. The text also links the inability to transmit surplus renewable energy to broader concerns about investor confidence and the pace of emissions reductions.

FY27 risk: 35 GW to 37 GW exposed, Crisil says

Crisil Ratings has warned that more than 35 GW of renewable energy capacity could face grid curtailment risk in FY27 due to limited long-term transmission access. The risk stems from capacity additions outpacing transmission deployment. The report also notes that extended curtailment can reduce project returns and weaken debt service coverage ratios (DSCR) and equity internal rates of return (IRR).

The text adds that, combined with 17 GW of existing TGNA capacity as of February 2026, the total capacity exposed to curtailment risk could reach 35 GW to 37 GW. That range sets a measurable marker for lenders and sponsors tracking execution risk beyond pure capacity addition targets.

Key reported indicators at a glance

Market impact: where the stress shows up

Curtailment directly reduces saleable electricity, which can lower utilisation and strain project economics when it persists. The text explicitly ties extended curtailment to weaker DSCR and lower equity IRR, highlighting why lenders and investors treat evacuation risk as a credit issue, not just a technical one. At the system level, the repeated need to back down solar when other sources are at limits signals a lack of grid flexibility.

There is also a planning signal for states and central agencies. With key 220 kV and 400 kV corridors described as increasingly congested, developers in Rajasthan and Gujarat face execution uncertainty around approvals, commissioning timelines, and realised generation. The presence of 31.8 GW of underutilised allocated connectivity suggests that “connectivity granted” is not the same as “power successfully evacuated and monetised.”

Why this matters: aligning supply, demand, and flexibility

The text frames the ultimate challenge as aligning renewable supply with demand, with the mismatch showing up first in high-RE states but remaining a national concern. As non-fossil sources rise toward a larger share of installed capacity, operators must balance variability, demand patterns, and transmission constraints. Ember’s Asia energy analyst Duttatreya Das is cited as saying curtailment due to transmission limitations is reaching concerning levels, reinforcing that the issue is moving from occasional operational friction to a structural constraint.

Grid modernisation is repeatedly implied as the practical lever, along with planning that links generation additions to transmission readiness and storage deployment. Without that synchronisation, the text suggests curtailment could become a binding constraint on the next phase of renewable growth.

Conclusion

India’s renewable curtailment data for Q1 2026, along with CERC connectivity indicators and company-level disclosures, point to a clear message: transmission and flexibility are lagging generation. With Crisil warning that 35 GW to 37 GW could be exposed to curtailment risk in FY27, the focus is shifting from capacity announcements to evacuation readiness and grid integration. The next phase of India’s renewable scale-up will depend on how quickly transmission upgrades, approvals, and balancing resources catch up to commissioning timelines.