TNERC Tamil Nadu Electricity Regulator: Solar Gross vs. Net Metering

Definition

Tamil Nadu Electricity Regulatory Commission (TNERC) regulates Tamil Nadu's electricity sector. Known for restrictive solar policy — net metering ≤ 10 kW (residential); gross metering above. TANGEDCO is the primary DISCOM.

Key Takeaways

TNERC = Tamil Nadu state electricity regulator.
Net metering only for ≤ 10 kW residential.
Above 10 kW: gross metering at low feed-in rates.
TANGEDCO is primary DISCOM.
Restrictive for commercial rooftop solar.

Why TNERC’s Policy Matters for Project Economics

TNERC’s decision to cap net metering at 10 kW residential — and push everything else onto gross metering — changes the underlying economics of a Tamil Nadu solar project compared to states like Karnataka or Gujarat, where net metering extends up to 1 MW. Under gross metering, a system’s exports are paid at TANGEDCO’s feed-in tariff rather than offset against the customer’s retail rate, so the value of each exported unit is set by the feed-in tariff rather than by how much the customer would otherwise have paid at retail. Any commercial or industrial rooftop proposal in Tamil Nadu above 10 kW needs to model cash flow on that gross-metering basis from the start, not assume net-metering-style bill offsetting.

TNERC vs. Other State Regulators

TNERC sits in the same role as KERC in Karnataka, MERC in Maharashtra, or GERC in Gujarat — a State Electricity Regulatory Commission (SERC) that issues the tariff and net metering orders its state’s DISCOMs must follow. Where TNERC differs is in how restrictive that policy is: the 10 kW net metering cap is one of the tightest in the country, and it’s why Tamil Nadu shows up as a stricter outlier in comparisons of net metering across Indian states.

Because TNERC’s gross-metering threshold changes how a commercial system’s export revenue is calculated, it’s worth running the numbers through a proper commercial solar ROI model before quoting a Tamil Nadu project above 10 kW. Our state-wise breakdown of solar permit processing times in India also covers how TNERC and TANGEDCO approval timelines compare to other states’ DISCOMs, which is useful context for scheduling. For the broader mechanics of how Indian net metering programs work state by state, Heaven Green Energy’s net metering guide explains the bidirectional-meter and billing-credit process that TNERC restricts more tightly than most other regulators.

Frequently Asked Questions

4 commonly searched questions about TNERC.

What's special about TNERC?

Tamil Nadu restricts net metering to ≤ 10 kW residential. Above 10 kW uses gross metering at feed-in tariff (~₹2.80/kWh in 2024). Less solar-friendly than Karnataka, Gujarat.

Who is TNERC and how does it relate to TANGEDCO?

TNERC is the state regulatory commission that sets tariff orders, net metering rules, and grid-connectivity regulations for Tamil Nadu. TANGEDCO is the DISCOM — the utility that actually implements TNERC's orders, processes interconnection applications, and bills customers.

Do commercial and industrial solar systems in Tamil Nadu get net metering?

No. Under current TNERC policy, net metering is reserved for residential systems up to 10 kW. Commercial and industrial systems, along with any residential system above that threshold, are billed under gross metering — all solar generation is sold to TANGEDCO at the feed-in tariff, and all consumption is billed separately at the retail rate.

Is CEIG approval still required for a gross-metered system in Tamil Nadu?

Yes. CEIG sign-off is a separate electrical-safety approval tied to system capacity, not to whether the project is net- or gross-metered. Larger commercial and industrial systems in Tamil Nadu typically need CEIG approval alongside their TANGEDCO gross metering application.