The Tamil Nadu Electricity Regulatory Commission issued Notification No. TNERC/GEOA/25-1/2025 on 18 September 2025, bringing into effect the Tamil Nadu Electricity Regulatory Commission (Terms and Conditions for Green Energy Open Access) Regulations, 2025. These regulations came into force upon their publication in the Tamil Nadu Government Gazette and apply across the entire state. They have been introduced to provide non-discriminatory open access for renewable energy through intra-state transmission and distribution systems, including incidental use linked to inter-state transmission.
The core objective is to create a framework for granting open access, determining charges such as transmission, wheeling, cross-subsidy, additional surcharges, banking charges, and others, while ensuring transparent and uniform treatment for green energy open access customers. Eligible customers include Extra High Tension (EHT) and High Tension (HT) consumers with a minimum contracted demand of 63 kVA, renewable energy generators, traders, and distribution licensees. Captive generating plants also have an automatic right to open access under these rules.
The regulations define the categories of open access into long-term (12 to 25 years), medium-term (3 months to 3 years), and short-term (up to 1 month). Priority has been set with distribution licensees first, followed by green energy open access customers, and then normal open access consumers. Within the green energy segment, long-term users get precedence over medium- and short-term ones. The principle of first-come, first-served will also guide approvals.
Applications will be processed through a single-window system. The Tamil Nadu State Load Dispatch Centre (SLDC) will function as the nodal agency for short-term transactions, while the State Transmission Utility (STU) will handle medium- and long-term open access approvals. No approval will be granted without consent from the concerned distribution licensee.
Banking of energy has been permitted, where surplus power injected into the grid can be adjusted against consumption within the billing cycle. Banking charges are fixed at 8% of banked energy in kind, while older wind projects commissioned before 31 March 2018 will continue under the earlier 12-month banking period with 14% charges. Any unutilised banked energy will be settled by the distribution licensee at 75% of the relevant renewable tariff or bid tariff.
Charges applicable to green energy open access customers include transmission and wheeling charges, cross-subsidy and additional surcharges, standby charges capped at 125% of the applicable tariff, banking charges, and deviation settlement charges. Concessions on charges will apply only for intra-state transactions, not for inter-state or power exchange purchases.
The regulations also mandate proper metering at both generator and consumer ends as per Central Electricity Authority norms, installation of real-time communication systems, and strict compliance with forecasting and deviation settlement mechanisms. Non-compliance in real-time communication can lead to the reduction or exclusion of a generator’s output from scheduling.
Curtailment priorities are also outlined, where short-term open access users will be curtailed first, followed by medium- and long-term users, with distribution licensees being the last to face curtailment.
The SLDC has been directed to issue detailed procedures within 90 days of notification, covering application formats, processing timelines, energy accounting, and communication requirements. It will also maintain a dedicated webpage providing updated information on approvals, system losses, congestion, and customer details.
These regulations are aligned with the Ministry of Power’s Electricity (Promoting Renewable Energy Through Green Energy Open Access) Rules, 2022, which aim to help India achieve its renewable energy target of 500 GW by 2030 and carbon neutrality by 2070. Tamil Nadu has been a pioneer in open access and renewable energy promotion, and by adopting these regulations, the Commission seeks to strengthen the state’s renewable integration while balancing grid security, economic efficiency, and consumer access.
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