Tamil Nadu has introduced a new regulatory framework to improve supervision, control and operation of its intra-State electricity system. The Tamil Nadu Electricity Regulatory Commission (TNERC) has issued the Tamil Nadu Electricity Grid Code 2026, replacing the earlier 2005 grid code.
The updated code incorporates provisions from the Indian Electricity Grid Code (IEGC) 2023 while including state-specific operational requirements. TNERC said the Grid Code sets out procedures to ensure fair and efficient handling of daily technical operations under both normal and abnormal grid conditions.
The commission noted that the code cannot predict every possible operational situation. In unforeseen circumstances, the State Load Despatch Centre (SLDC) and the State Transmission Utility (STU) may take necessary actions to maintain grid stability. Grid users are required to extend reasonable cooperation to support such measures.
Under the new framework, the SLDC is authorised to levy and collect fees and charges from generating companies and intra-State transmission licensees, as approved by the commission.
TNERC will approve the formation of a Grid Code Review Committee through a separate order after receiving a proposal from the SLDC within 30 days of the code’s issuance. The STU must notify all grid users in writing about the chairman and members of the committee within 15 days of its formation, including any later changes.
Planning Focus on Renewables and Flexibility
The code emphasises long-term planning of generation and transmission resources to meet future demand while maintaining reliability standards. It calls for an optimal energy mix with greater use of environmentally friendly technologies, flexible generation, energy storage systems for energy shifting, and demand response mechanisms to manage renewable variability.
The STU will be responsible for preparing a rolling transmission plan for the State Transmission System, covering short-term (up to five years), medium-term (up to 10 years), and long-term (up to 15 years) periods.
Trial Run and Commercial Operation Norms
The Grid Code outlines detailed trial run requirements for solar, wind, energy storage systems, pumped storage projects, and hybrid generating stations connected to the State Transmission System.
Solar and wind projects must conduct trial runs for a minimum capacity of 5 MW, with larger projects allowed to complete trials in phases. Projects of 50 MW or more may conduct trials in instalments covering at least 20% of total capacity.
If rated capacity cannot be demonstrated, developers may repeat the trial or opt for de-rating, subject to minimum capacity conditions. Before declaring commercial operation date (COD), projects must submit a certificate signed by an authorised signatory not below CMD, CEO or MD rank confirming compliance with Central Electricity Authority standards and Grid Code provisions.
For renewable projects of 5 MW or more, COD will be declared after successful trial runs and completion of required conditions.
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