Guide · Tamil Nadu · TANGEDCO
Net metering for rooftop solar in Tamil Nadu (TANGEDCO): how it works
Net metering is what makes a grid-connected rooftop system pay for itself. This is the Tamil Nadu companion to our Karnataka net-metering guide — same plain-English structure, with the TANGEDCO and TNERC specifics and an honest note on where the two states differ.
Net metering in one line
Your rooftop system usually makes the most power at midday — often more than your home is using at that moment. A grid-connected system exports that surplus to the grid, a bidirectional meter records both what you export and what you import, and you are billed on the net. The units you send out during the day offset the units you draw at night, which is why higher-bill homes tend to see the fastest payback.
How TANGEDCO settles your solar
There is an important nuance in Tamil Nadu that homeowners should understand before sizing a system. The state has, across successive TNERC solar orders, applied more than one settlement mechanism to rooftop solar — net metering (exports offset imports one-for-one), net feed-in (exports are metered separately and paid at a specified feed-in rate), and net billing (a hybrid where imports and exports are valued at different rates). Which mechanism currently applies to a domestic connection is a verify-before-you-buy item: it is set by the TNERC order in force, not by your installer, and it materially changes how much your exported units are worth.
Under a true net-metering mechanism, exported units offset imported units within a billing cycle and any surplus is carried forward or settled at the end of the settlement period. Under a feed-in or net billing mechanism, exports are credited at a defined rate that can be lower than the retail tariff you pay for imports. Do not assume a one-for-one offset — confirm the current mechanism and the export credit rate for residential connections directly with the source.
Last verified: July 2026. Sources: tangedco.tn.gov.in and the current solar order at tnerc.tn.gov.in. RainbowHome does not fix these terms; treat the TNERC order as the source of truth.
The bidirectional meter, and who applies
Net metering replaces your ordinary meter with a bidirectional one that counts both directions of flow. You do not arrange this yourself — a MNRE-empanelled installer typically handles the TANGEDCO connection application, feasibility approval, the bidirectional-meter installation and the grid-synchronisation paperwork as part of the project. Your part is supplying documents: your latest electricity bill, proof of ownership and ID.
When you compare installers, confirm the net-metering application and the meter are included in the quoted price rather than billed as an extra. We explain how we compare installers on how we rank and methodology.
Capacity limits and sanctioned-load rules
How large a rooftop system you can connect is generally governed by two things rather than a single flat cap:
- Your sanctioned load. The permitted rooftop capacity has historically been expressed relative to your sanctioned load. If you want a larger system than your current sanction supports, you may need to apply for a load enhancement first.
- The distribution-transformer limit. There is also a cap on how much total rooftop solar can sit on a shared distribution transformer or feeder, so your local headroom depends on how much solar neighbours have already connected.
Both of these have been revised across successive TNERC orders, so treat any specific percentage or kilowatt figure as a range to verify for your connection, not a fixed rule. Your installer checks your available headroom with TANGEDCO before finalising system size.
Last verified: July 2026. Confirm current capacity and sanctioned-load rules with tnerc.tn.gov.in and tangedco.tn.gov.in.
A rooftop system may also qualify for potential government subsidies*. *Subsidy eligibility and amounts are set by the government, change periodically, and are never guaranteed — verify current terms at mnre.gov.in.
What differs versus Karnataka
The mechanics are similar — a bidirectional meter, net settlement, and the installer handling the DISCOM application — but two things differ in practice:
- Who runs the grid. In Karnataka it is BESCOM and the other ESCOMs under KERC; in Tamil Nadu it is TANGEDCO under TNERC.
- The settlement mechanism.Karnataka has largely run a net-metering model for residential rooftop, whereas Tamil Nadu has moved between net metering, net feed-in and net billing across orders. That makes verifying Tamil Nadu's current residential mechanism more important than in Karnataka.
Read the companion guide: net metering for rooftop solar in Karnataka. For the general concept across states, see our net metering explainer.
See what solar saves on your Tamil Nadu bill
Run a free estimate for your home, then compare installers who handle the TANGEDCO net-metering application for you. No sales call, no quote form.
Coverage: Karnataka and Tamil Nadu.
FAQ
How does net metering work with TANGEDCO in Tamil Nadu?
Your rooftop system exports the surplus power it makes during the day to the grid. A bidirectional meter records both the units you export and the units you import from TANGEDCO, and your bill is settled on the net — the units you export are set against the units you draw. The exact settlement mechanism and credit treatment are fixed by the TNERC solar order in force, so confirm the current terms for a residential connection before you size a system.
Does Tamil Nadu use net metering or net feed-in for home solar?
Tamil Nadu has applied more than one mechanism over successive TNERC orders — net metering, net feed-in, and net billing have all featured for different consumer categories and system sizes. Which one currently applies to a domestic rooftop connection is a verify-before-you-buy item: it is set by the TNERC order in force, not by the installer. Ask your MNRE-empanelled installer and TANGEDCO to confirm the mechanism, and check the latest TNERC order directly.
Who applies for net metering in Tamil Nadu — me or my installer?
Your MNRE-empanelled installer typically handles the TANGEDCO connection application, the bidirectional-meter installation, feasibility approval and the grid-synchronisation paperwork as part of the project. You supply documents such as your latest electricity bill, proof of ownership and ID. When you compare installers, confirm the net-metering application and meter are included in the quoted price.
What is the maximum rooftop solar capacity TANGEDCO allows on a home?
Rooftop capacity is generally tied to your sanctioned load and to a distribution-transformer limit, rather than being a single fixed number. Historically the domestic cap has been expressed as a percentage of sanctioned load, and the transformer-level cap limits total rooftop solar on a shared feeder. Because these limits have been revised across TNERC orders, treat any specific figure as a verify item and confirm your headroom with TANGEDCO for your connection.
How are exported solar units credited on the TANGEDCO bill?
Under a net-metering mechanism, exported units offset imported units one-for-one within a billing cycle, and any surplus is carried forward or settled at the end of the settlement period per the tariff order. Under a net feed-in or net billing mechanism, exports are instead paid or credited at a specified feed-in rate that can differ from the retail tariff. The credit rate and carry-forward rules come from the TNERC order in force — verify the current numbers rather than assuming a one-for-one offset.
Is net metering different in Chennai versus the rest of Tamil Nadu?
The rules are set state-wide by TNERC and administered by TANGEDCO, so the core mechanism is the same across Tamil Nadu, including Chennai. What varies locally is practical: feeder and distribution-transformer headroom, inspection scheduling, and how busy your local TANGEDCO section office is. Your installer confirms the current terms for your specific connection.