What is RE curtailment? Examine how grid infrastructure and battery storage can help India meet its renewable energy targets.

Renewable energy (RE) curtailment happens when grid operators deliberately cut solar or wind output to keep the grid stable, because the network cannot carry or absorb the power [1]. Solar and wind make up 37% of installed capacity but only 13% of generation [2]. This gap shows that India's RE bottleneck has moved from generation to transmission and storage.

Why curtailment occurs

• Evacuation gap: solar parks come up in one or two years, but lines take longer. Only 58% of targeted transmission lines were added in 2024-25 [2].
• Intermittency: solar output peaks at midday while demand peaks in the evening, so the midday surplus is wasted.
• Weak execution: GEC Phase-I met only about 44% of its substation target by December 2020. The Standing Committee on Energy blamed inadequate MNRE monitoring [3].

Role of grid infrastructure

• Intra-state corridors: GEC Phase-II adds about 10,750 ckm of lines and 27,500 MVA of substation capacity. It evacuates about 20 GW in seven States with 33% Central Financial Assistance, supporting the 450 GW by 2030 target [4].
• Scale-up: GEC Phase-III has an outlay above ₹1.86 lakh crore, of which ₹1.36 lakh crore is for intra-state transmission. It will integrate up to 135 GW across States and UTs by FY 2032-33 [1].
• Economic gain: when less power is curtailed, the RE plants already built earn more on their investment.

Role of battery storage

• Time-shifting: Phase-III is the first GEC phase with storage, putting ₹50,000 crore into 50 GWh of BESS to move midday surplus to peak hours and support grid stability [1].
• Enablers: viability gap funding for BESS and a customs-duty exemption on capital goods for making battery cells (Budget 2026-27) [2].
• Limits: 50 GWh can supply roughly 12.5 GW for four hours. That smooths evening peaks but cannot cover long cloudy or windless spells. Cells and transmission materials also still depend on imports [2].

Way forward

• Publish State-wise physical progress (lines, substations, batteries), not just the money released [3].
• Use concessional finance such as Germany's €1 billion soft loan for GEC [5] to reduce the borrowing burden on State utilities.
• Place batteries at congested grid nodes and push DISCOM reform so that States can pay for new lines.

Transmission removes network bottlenecks and storage absorbs surplus power, so together they turn installed RE capacity into actual generation. If execution is monitored well and financing is shared fairly between the Centre and States, GEC-III can deliver India's RE targets and advance SDG-7 (affordable, clean energy) and its Paris commitments.