‘Transmission constraints threaten India’s renewable energy expansion’

1. At a Glance

• Transmission bottlenecks, not generation capacity, are now the binding constraint on India's renewable energy (RE) rollout — projects are built but power cannot be evacuated [1].
• Curtailment (forced reduction/stoppage of generation due to grid congestion) is rising sharply among newly commissioned solar/wind projects, especially those without firm transmission access [1] [2].
• Directly tests GS-III (infrastructure, energy security, environment) and links Budget/NEP-II targets with real execution gaps — a recurring PT/Mains theme.
• Reveals the gap between India's ambitious RE capacity targets (>35% generation share by 2029-30) and the pace of transmission infrastructure buildout [3] [1].

2. Why in the News

• Rating agency ICRA, in a statement dated 19 August 2026, flagged that insufficient inter-State transmission lines are forcing many solar projects into daylight-hour curtailment [1].
• ICRA data: ~37% of RE capacity at affected substations in northern, western, and southern regions operates under Temporary General Network Access (T-GNA), facing 30–50% curtailment during the day [1].
• Peak curtailment figures (as of 6 August 2026): 8,617 MW in western India (~55% of affected capacity under T-GNA) and 5,573 MW in the northern region [1].
• A separate ICRA report (July 2026) found 33% of 54.8 GW of recently commissioned RE capacity is evacuated via T-GNA nationally, with solar-hour curtailment of 50–60% [2].
• Only 12% of TBCB (Tariff-Based Competitive Bidding) transmission projects met their Scheduled Commercial Operation Date (SCOD); median delay exceeded 10 months [2].

3. Background & Evolution

• India's RE push accelerated post-2015 with the 175 GW by 2022 target, later revised to 500 GW non-fossil capacity by 2030 (COP26, Glasgow, 2021).
• Transmission planning for RE evacuation is done via the Inter-State Transmission System (ISTS), built mainly through Tariff Based Competitive Bidding (TBCB).
• Green Energy Corridors scheme launched to strengthen intra-State and inter-State transmission for RE-rich states (Rajasthan, Gujarat, Tamil Nadu, Karnataka, Andhra Pradesh, Himachal Pradesh).
• NITI Aayog's Renewable Electricity Roadmap 2030 projects ~335 GW of transmission network needed to connect 280 GW of Variable RE (VRE) to the ISTS [3].
• Government approved ISTS schemes worth ₹13,595 crore to evacuate 9 GW of RE power from Rajasthan and Karnataka [3].
• T-GNA mechanism introduced as a short-term/interim solution allowing RE generators to use spare ISTS capacity for periods from a single time block up to ~11 months, pending long-term access [1].

4. Core Static Facts

5. Multi-Dimensional Analysis

Economic

• Prolonged T-GNA/curtailment erodes generator revenues, raising operational costs and financing risk for RE developers, potentially deterring future bidding — RE bidding activity fell from 40.6 GW (FY25) to 14.7 GW (FY26) [2].
• Transmission capex needs (₹5–6 trillion) imply major financing requirements for POWERGRID and private TBCB players.

Environmental

• Curtailment effectively wastes clean generation capacity already built, undermining India's climate commitments (NDC, Panchamrit goals) by keeping fossil-based backup running longer.

Administrative

• Core issue is execution mismatch: generation capacity addition (RE) is outpacing transmission capacity addition — a federal coordination problem between State transmission utilities (STUs) and Central Transmission Utility.
• Delays in TBCB project completion (median >10 months) reflect land acquisition, right-of-way, and contractor execution bottlenecks.

Scientific/Technological

• Highlights need for grid-scale battery storage, smart demand forecasting, and better grid flexibility instruments to absorb variable solar/wind output [3].

Governance

• Raises transparency questions on whether transmission planning (CEA) is adequately synchronized with RE capacity auctions (SECI/MNRE), a recurring critique from the Forum of Regulators [3].

6. Recent Developments (last 12-18 months)

• July 2026: ICRA reported 33% of 54.8 GW newly commissioned RE capacity evacuated via T-GNA; solar-hour curtailment 50–60% [2].
• 19 August 2026: ICRA flagged 37% of RE capacity at affected substations in northern/western/southern regions under T-GNA, facing 30–50% daytime curtailment; peak curtailment 8,617 MW (west) and 5,573 MW (north) as of 6 August 2026 [1].
• August 2026: ICRA noted RE project bidding activity dropped sharply to 14.7 GW in FY26 from 40.6 GW in FY25 [2].
• Government approved ISTS transmission schemes worth ₹13,595 crore for evacuating 9 GW RE power from Rajasthan and Karnataka [3].
• CERC proposed transmission charge relief for delayed RE projects to cushion developers hit by evacuation delays [2].

7. Prelims Hooks

• Curtailment = forced reduction/stoppage of power generation due to oversupply or grid congestion [1].
• T-GNA (Temporary General Network Access) permits interim ISTS use for periods from a single time block up to ~11 months [1].
• ICRA (19 Aug 2026): 37% of affected RE capacity under T-GNA faces 30–50% daytime curtailment [1].
• Peak curtailment as of 6 August 2026: 8,617 MW (western region), 5,573 MW (northern region) [1].
• Western India: ~55% of curtailment-affected RE capacity is under T-GNA [1].
• ICRA (July 2026): 33% of 54.8 GW newly commissioned RE capacity evacuated via T-GNA nationally [2].
• TBCB = Tariff Based Competitive Bidding, the procurement mode for ISTS transmission projects.
• Only 12% of TBCB transmission projects met their Scheduled Commercial Operation Date (SCOD) [2].
• Median delay in TBCB project commissioning: over 10 months [2].
• NITI Aayog estimates ~335 GW transmission network needed to connect 280 GW Variable RE to ISTS [3].
• Government-approved ISTS scheme value: ₹13,595 crore to evacuate 9 GW RE power from Rajasthan and Karnataka [3].
• RE is projected to contribute more than 35% of India's power generation by 2029-30 (article headline data point).
• RE project bidding fell from 40.6 GW (FY25) to 14.7 GW (FY26) — attributed partly to curtailment risk [2].
• Nodal regulator for transmission tariffs/access: Central Electricity Regulatory Commission (CERC).
• ICRA's Girishkumar Kadam (SVP & group head, corporate ratings) highlighted need for timely intra-/inter-State transmission execution plus storage capacity [article excerpt].

8. Mains Relevance

• GS-III: Infrastructure — energy; Conservation, environmental pollution and degradation; Achievements of Indians in science & tech (renewable tech); Economic growth and development.
• GS-II (secondary): Governance issues — Centre-State coordination in infrastructure planning.
• Possible question stems: 1. "Transmission infrastructure, not generation capacity, is emerging as the binding constraint on India's renewable energy transition." Discuss the causes and suggest policy measures. (GS-III, 15 marks) 2. Examine the role of mechanisms like Temporary General Network Access (T-GNA) in India's renewable energy evacuation framework. How do they affect the financial viability of RE projects? (GS-III, 10 marks) 3. "India's renewable energy targets cannot be met without matching transmission and storage infrastructure." Critically analyze with reference to recent curtailment trends. (GS-III, 15 marks)

9. Related Topics to Study Next

• Green Energy Corridors Scheme — the flagship scheme for transmission strengthening for RE evacuation.
• National Electricity Plan (NEP-II) — sets transmission and generation targets this shortfall is measured against.
• Battery Energy Storage Systems (BESS) policy — key mitigation for curtailment via storage.
• One Nation One Grid / National Grid — the broader integrated transmission architecture RE depends on.
• India's NDC and COP26 commitments (500 GW non-fossil by 2030) — the target this bottleneck threatens.
• CERC transmission tariff regulations — governs cost-sharing/access rules like T-GNA and General Network Access (GNA).
• PM-KUSUM / PM Surya Ghar schemes — decentralized RE that partly bypasses ISTS bottlenecks.
• Forum of Regulators reports on RE integration — institutional body flagging these very issues.

10. Common Errors / Trap Areas

• Do not confuse T-GNA (Temporary General Network Access, short-term) with GNA (General Network Access, long-term/firm access) — the article specifically concerns T-GNA vulnerability.
• Do not attribute transmission planning to MNRE — it is primarily a CEA/POWERGRID (CTU)/CERC function; MNRE handles generation-side policy.
• Avoid confusing "curtailment" with "outage" — curtailment is a deliberate grid-management response to oversupply/congestion, not equipment failure.
• Do not assume all regions are equally affected — southern region shows comparatively limited curtailment vs. western (Rajasthan, Gujarat) and northern regions [2].
• The >35% RE generation share figure is a projection for 2029-30, not current RE share — avoid stating it as present-day figure.