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Grid India Suggests Transmission Margin and Operating Fees for Full T-GNA Utilization

Grid-India Proposes Amendments to T-GNA Procedure

The Grid Controller of India (Grid-India) has proposed several amendments to the Central Electricity Regulatory Commission (CERC) draft procedure governing temporary general network access (T-GNA) to the interstate transmission system. Stakeholders have been invited to submit their feedback by October 30, 2025.

Transmission Margin for Full Capacity

Grid-India has recommended maintaining sufficient transmission margins to ensure that power projects can schedule generation up to their full approved T-GNA capacity. It also clarified that entities registered under the National Open Access Registry (NOAR) for short-term access will now need to register with their respective Regional Load Dispatch Centers (RLDCs) for T-GNA approvals. Additionally, similar margins will be applied to projects with general network access (GNA) to facilitate full-capacity scheduling.

Bi-Monthly Standing Clearance Process

For cases where GNA is yet to take effect, RLDCs will identify eligible generating stations and issue bi-monthly standing clearances for deemed T-GNA based on available transmission margins. Renewable projects connected to a pooling station via deemed T-GNA will be treated on par with GNA projects awaiting activation.

Applications for the 1st–15th of each month must be submitted within 24 hours of the 25th day of the preceding month, while those for the 16th–end of the month must be filed by the 10th day of the current month. Submissions received within deadlines will be processed on a pro-rata basis, while late submissions will follow a first-come, first-served approach.

For hybrid power projects with or without energy storage, clearances can be issued up to the installed capacity, provided scheduling remains within the approved connectivity quantum. Entities holding T-GNARE (T-GNA for renewable projects) may convert it into regular T-GNA by applying to the nodal RLDC, with power delivery permitted after four months from the application date.

Margin Calculation Formula

For advance bilateral transactions, Grid-India proposed the following formula to determine export T-GNA margins:

Export T-GNA Margin = Export Available Transfer Capacity – (A% × Export PPA Quantum + Approved Advance T-GNA)

The ‘A’ factor—accounting for renewable variability and system exigencies—will be periodically set by the National Load Dispatch Center (NLDC). PPA quantum data will be derived from contract details submitted during GNA or T-GNA scheduling.

Operating Charges

Applicants seeking bilateral or collective T-GNA must pay operating charges to the host RLDC along with Interstate Transmission System (ISTS) fees. Non-payment will trigger automatic blocking through NOAR, and the released transmission margin will be reassigned.

For advance or exigency T-GNA under bilateral transactions, operating charges are Rs 1,000 (~$11.3) per day. Entities already paying RLDC fees under existing regulations will be exempt from duplicate charges for the same capacity. In collective transactions, both buyers and sellers will pay NLDC operating charges via power exchanges at Rs 1 (~$0.01)/MWh, capped at Rs 200 (~$2.26) per day.

If drawal schedules exceed approved GNA or T-GNA capacity, additional operating charges will apply. SLDCs must submit entity-wise schedule data to NLDC by 2:00 PM the following day, after which NLDC will release exchange-wise payment details by 5:00 PM. If SLDC data is delayed, NLDC will proceed using available information. T-GNA collective transaction charges must be paid by midnight of the next day through exchanges to NLDC. Operating charges will also apply for alternate scheduling as per the Indian Electricity Grid Code.

Payment and Compliance Timeline

For advance T-GNA or T-GNARE scheduled within the next three working days, the first month’s transmission charges must be paid by 4:00 AM on the day before scheduling. Payments for subsequent months are due two days before the end of each month. Failure to comply will lead to automatic blocking in NOAR.

In cases of curtailment, transmission constraints, or revised transactions, the nodal agency will refund operating and ISTS charges by the 15th of the following month. If no discrepancies are raised within 15 days, reconciliation will be considered final.

Regulatory Context

This proposal follows CERC’s recent notification of the Connectivity and GNA to the Interstate Transmission System (Third Amendment) Regulations, 2025, which updated previous provisions by broadening definitions, simplifying withdrawal procedures, revising bank guarantee norms, and strengthening compliance obligations for renewable energy and storage developers.