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Last Reviewed: October 5, 2026 •
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Tamil Nadu TNERC Solar Net Metering and Grid Export Settlement Workflow
Tamil Nadu Solar Net Metering Guide: TANGEDCO Regulations (2026)
This Tamil Nadu Solar Net Metering Guide explains how to bank daytime surplus with TANGEDCO and draw it back at night. Understanding the settlement rules is the difference between good and great savings.
Tamil Nadu net metering at a glance: TNERC regulations · TANGEDCO is the single-window DISCOM · monthly settlement · check the latest TANGEDCO procedure on the portal before sizing above 10 kW.
📋 The 1:1 Unit Offset Rule:
Under TANGEDCO, residential solar works on a true net metering model. Every unit of electricity you export to the grid is deducted on a 1-to-1 basis from the units you import. If you import 450 units in a billing month and export 350 units, you are billed only for the net difference of 100 units.
Capacity and Sanctioned Load Limits
TANGEDCO limits the size of your rooftop solar plant based on your existing grid connection parameters:
Sanctioned Load Limit: The maximum solar capacity you can install under net metering is capped at **100% of your sanctioned load** (measured in kW). If your sanctioned load is 3 kW, you cannot install a 4 kW system without first upgrading your load capacity.
Transformer Load Limit: TANGEDCO restricts the cumulative solar capacity in any local area to **80% of the distribution transformer's capacity**. If your local transformer is overloaded with existing solar systems, your feasibility request might be delayed or rejected.
The Annual Settlement Cycle (March 31st)
What happens if your solar panels generate more units than you consume in a month?
In Tamil Nadu, surplus solar units are carried forward in your electricity ledger month-over-month. The settlement cycle runs from **April 1st to March 31st** of the following year. At the end of the financial year (March 31st), if you still have surplus energy credits, TANGEDCO purchases those units at the **Average Power Purchase Cost (APPC)**, which is approximately ₹3.50 per unit. This credit is adjusted in your next billing cycle.
Bi-Directional Meter Specifications & Testing
To enable net metering, you must replace your standard electricity meter with an approved bi-directional net meter. The meter must comply with the CEA (Central Electricity Authority) standards. You can either purchase the meter from TANGEDCO or buy a compatible model from the open market and get it tested at an empanelled TANGEDCO testing lab.
Your Solar Journey Continues
Keep reading the Tamil Nadu cluster to ensure a successful rooftop installation:
Official 2026 Consumer Rights & DISCOM Escalation Protocol in Tamil Nadu
Under the latest regulations notified by the Tamil Nadu Electricity Regulatory Commission (TNERC) and MNRE guidelines, consumers across Chennai, Coimbatore, Madurai, Tiruchirappalli, Salem and Tirunelveli are legally protected by strict Service Level Agreements (SLAs). If your rooftop solar net meter installation, feasibility inspection, or subsidy disbursement is delayed, follow this formal escalation hierarchy:
Escalation Level
Designated Authority
Mandated SLA Timeline
Action & Remedy
Level 1: Local Sub-Division
Assistant Engineer / Junior Engineer (TANGEDCO (Tamil Nadu Generation and Distribution Corporation Ltd), TANGEDCO)
3 Working Days
Submit written grievance ticket regarding net meter testing or portal document hold.
Level 2: Circle Superintending Engineer
Executive Engineer (Solar Renewable Cell)
7 Working Days
Formal grievance filing on DISCOM portal with application acknowledgement number.
Level 3: Regulatory Ombudsman
Consumer Grievance Redressal Forum (CGRF) under Tamil Nadu Electricity Regulatory Commission (TNERC)
15 Working Days
Binding legal hearing. Utility can be fined daily penalties for willful commissioning delays.
Mandatory Inspection Documents Checklist
When the DISCOM inspection team visits your premises for the final bi-directional meter synchronization, have these exact physical documents signed and organized in a physical file:
Joint Inspection Report (JIR): Signed by the homeowner and the empanelled solar engineer.
Factory Flash Test Report: Showing peak watt test results matching your panel serial numbers.
DCR Undertaking Stamp Paper: Affirming domestic solar cell content as mandated by MNRE.
Inverter Type Test Certificate: Confirming anti-islanding compliance (IS 16221 / IS 16169).
💡 Consumer Tip: Always keep a timestamped digital copy of your Work Completion Report (WCR) and joint inspection form. If your net meter is not installed within 15 days of successful plant inspection, your vendor can register a formal complaint on the PM Surya Ghar National Grievance Portal.
5. In-Depth Energy Banking & Settlement Regulations in Tamil Nadu
Net metering rules in Tamil Nadu are established by TNERC (Tamil Nadu Electricity Regulatory Commission). The fundamental principle is that the power grid functions as an infinite, 100% efficient virtual battery for your rooftop system:
1:1 Energy Offset: Every kilowatt-hour (unit) you push into the grid during daytime hours offsets exactly one unit consumed from the grid during nighttime on a 1:1 basis, saving electricity at your highest retail tariff slab.
Settlement Cycle: Surplus banked units roll over month to month throughout the financial year (April 1 to March 31). In months with heavy air conditioning use, you automatically draw upon credits accumulated during mild spring months.
Annual Buyback Settlement: On March 31, if you still have remaining surplus units in your credit account, your DISCOM (TANGEDCO (Tamil Nadu Generation and Distribution Corporation Ltd), TANGEDCO) settles and buys out the remaining units at predetermined regulatory rates (typically ₹2.00 to ₹3.00 per unit).
Net Meter Register
Direction of Electricity
Billing Formula
Import Register (kWh)
Power drawn from grid at night or rainy days
Total units consumed from utility
Export Register (kWh)
Surplus solar power sent into neighborhood grid
Total clean units exported
Net Billed Energy Units
Billed amount = (Import Units - Export Units)
If Export > Import, Energy Charge = ₹0 + Surplus Units Banked!
7. Net Metering vs. Gross Metering: What Consumers in Tamil Nadu Must Know
Understanding the fundamental billing difference between net and gross metering protects you from unfavorable contract terms:
Net Metering (Residential Homes up to 10kW): You save electricity at your full retail tariff rate (undefined). Units exported cancel out units imported 1:1, delivering the fastest 3-year payback.
Gross Metering / Net Billing (>10kW or Commercial): All solar generation is exported to the grid at a pre-fixed feed-in rate (typically ₹2.50 to ₹3.00/unit), while power consumed is purchased at full commercial tariff rates. This model extends the payback period to 5-6 years.
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