Most EPCs quoting rooftop work in Tamil Nadu ask one question: “What does the Tamil Nadu solar policy allow?” The honest answer is that no single document holds the rules. A 2019 government policy sets the direction. A TNERC tariff order sets the money. And the distribution company’s procedures decide whether your file moves.
Quick answer. Tamil Nadu solar policy in 2026 rests on four layers. The Tamil Nadu Solar Energy Policy 2019 sets targets and caps consumer systems at 100% of sanctioned load. TNERC Order No. 8 of 2021 sets metering options, feed-in tariffs and network charges. TNERC’s 2024 draft regulations propose group and virtual net metering. TNPDCL, the renamed TANGEDCO, runs the application. Check the latest TNERC order before you quote.
TL;DR
- The 2019 policy is still the state's latest solar policy we could verify. It targeted 9,000 MW by 2023.
- Domestic consumers get net metering. Other LT consumers get net feed-in, where exports earn a feed-in tariff.
- Network charges apply to every generated unit under net metering and net feed-in. Leave them out and your payback model is wrong.
- Group and virtual net metering appear in TNERC's 2024 draft. Treat them as proposals until you see a notified regulation.
This guide is for EPC owners and design leads who bid C&I and residential rooftop work in Tamil Nadu. For the step-by-step application and drawing formats, use our TANGEDCO solar net metering guide. This page explains the rules that sit above that process.
Which documents make up the Tamil Nadu solar policy?
Four documents decide what you can build and what the customer earns. Each one answers a different question.
| Layer | Document | Issuer | What it decides |
|---|---|---|---|
| Policy | Tamil Nadu Solar Energy Policy 2019 | Government of Tamil Nadu | Targets, consumer and utility categories, size cap, meter timelines |
| Tariff and metering | Order No. 8 of 2021 (GISS), effective 22 October 2021 | TNERC | Net metering vs net feed-in, feed-in tariffs, network charges |
| Proposed rules | Draft GISS Regulations, 2024 | TNERC | Group and virtual net metering, fees (draft) |
| Procedure | Rooftop solar procedures and portal | TNPDCL (formerly TANGEDCO) | Application, feasibility, meters, commissioning |
The 2019 policy replaced the 2012 policy, which first introduced net metering in the state. That history comes from a consumer booklet by the Chennai-based Citizen consumer and civic Action Group (CAG), which summarises both the policy and the 2021 order.
What does the 2019 policy actually say?
The policy set a target of 9,000 MW of solar by 2023, with 40% reserved for consumer category systems such as rooftops. Mercom India reported the same target when the policy was announced in February 2019.
The clauses that matter for design are short:
- Size cap. A consumer category system cannot exceed 100% of the sanctioned load at the service connection.
- Meter timeline. The distribution licensee must install meters and commission the metering within three weeks of the consumer’s application.
- Bidirectional by default. New and replaced service meters should be able to record import and export.
- HT consumers. TNERC open access rules apply. Wheeling below 1 MW is not allowed.
- Tax. Consumer category solar was exempt from electricity tax for two years from the policy’s publication.
The 2023 target date has passed. We could not find a newer state solar policy notified by the Energy Department as of October 2026. If one appears, it will change the targets, not the TNERC tariff rules below.
How do net metering, net feed-in and gross metering differ in Tamil Nadu?
TNERC’s 2021 order gives each consumer type one default route. The TANGEDCO salient features note on the GISS order sets out the split: domestic consumers use net metering, and other LT categories use net feed-in.
| Mechanism | Who uses it | Size limit | How surplus is treated |
|---|---|---|---|
| Net metering | Domestic consumers | Up to sanctioned load | Units offset units. Surplus at year end lapses |
| Net feed-in (net billing) | Other LT categories, except huts and agriculture | Sanctioned load or 999 kW, whichever is lower | Exports earn a feed-in tariff. Credit carries over or is paid out |
| Gross metering | Consumers above 150 kW and non-consumer generators | 151 kW to 999 kW | All generation is sold at the feed-in tariff |
Two grid limits sit on top, according to the CAG booklet. Rooftop solar on a distribution transformer is capped at 90% of its capacity for net metering or net feed-in. The cap is 70% for gross metering.
That transformer limit is the one that surprises EPCs. A strong rooftop design can still stall because the local transformer is already loaded with solar. Ask for the transformer status before you finalise the layout.
What feed-in tariffs did TNERC set?
TNERC fixed levelised feed-in tariffs by system size in the October 2021 order, as reported by Renewable Watch (2021).
| System size (kW) | Feed-in tariff (₹/kWh) |
|---|---|
| 1 to 10 | 3.61 |
| 11 to 150 | 3.37 |
| 151 to 999 | 3.10 |
The order also added a time-of-day incentive. Exports between 6 PM and 10 PM earn 20% more than the base feed-in tariff. That only helps a site with storage, because a plain PV array produces almost nothing after 6 PM.
The order’s control period ran to 31 March 2023. The TANGEDCO note says the utility continues to apply it. Confirm with TNERC that no later tariff order has replaced it before you put these numbers in a proposal.
How do network charges change the payback?
Network charges are the line item most proposals miss. The 2021 order levies them on the total units your system generates, not only on exports. Gross metering is exempt.
Per the TANGEDCO note, the rates are:
- ₹1.27/kWh for LT prosumers;
- ₹0.83/kWh for HT prosumers;
- domestic consumers pay 20% of the LT rate up to 10 kW, and 75% above 10 kW.
Critics argue consumers already pay fixed charges for the network. CAG covers that debate in its note on network charges on rooftop solar. For an EPC, the debate matters less than the arithmetic.
Worked example: an LT commercial rooftop
Take an LT commercial customer on net feed-in with a 100 kW system. Assume it generates 1,000 units in a billing period and exports 200 of them. These are round numbers for illustration, not a yield forecast.
| Line | Calculation | Value (₹) |
|---|---|---|
| Network charge | 1,000 units x ₹1.27 | 1,270 |
| Export credit | 200 units x ₹3.37 | 674 |
| Net from the export side | 674 minus 1,270 | -596 |
The export credit does not cover the network charge. The project only pays back through the 800 units consumed on site, which avoid the retail tariff. So the sizing rule for Tamil Nadu C&I is simple: size to daytime load, not to roof area.
What do the 2024 draft regulations propose?
TNERC published draft Grid Interactive Solar PV Energy Generating Systems Regulations in 2024 to replace the 2021 regulations. Public comments closed on 15 July 2024, per Mercom India.
The draft proposes:
- Group net metering for domestic consumers, so surplus at one service can offset others in the same name. A 7% line loss would be deducted.
- Virtual net metering for the utility, government and local bodies, with a 7% line loss and 8% banking charge.
- Reverse power relay connections up to sanctioned demand, with network charges on all generation.
DT Next (June 2024) reported the line loss and banking figures. We could not confirm a final notified version by October 2026. Do not sell group or virtual net metering to a client until TNERC publishes the final text.
Who runs the application now: TANGEDCO, TNPDCL or TNGECL?
The state split TANGEDCO in 2024 under the Tamil Nadu Electricity Restructuring and Transfer Scheme. The Energy Department approved the plan on 24 January 2024 through G.O. (Ms) No. 6 and No. 7.
- TNPDCL (Tamil Nadu Power Distribution Corporation Limited) is the renamed TANGEDCO. It handles distribution, so your rooftop application goes here.
- TNGECL (Tamil Nadu Green Energy Corporation Limited) took over green generation and absorbed TEDA, the old nodal agency.
- TNPGCL took over thermal generation.
TNPDCL describes the change on its restructuring page. Older forms and drawings still say TANGEDCO. That is normally fine, but use the current entity name on new agreements.
What does this mean for an EPC’s design file?
The rules above turn into five checks before a drawing set leaves your office.
- Confirm the mechanism. Domestic, LT non-domestic and HT consumers follow different routes. Label it on the single-line diagram.
- Check sanctioned load. System AC capacity must not exceed it. Ask for a load enhancement first if needed.
- Ask for transformer headroom. The 90% and 70% limits can block an otherwise sound design.
- Model network charges. Put them in the proposal as a separate line.
- Plan the inspection route. Larger systems need Electrical Inspectorate approval. Our CEIG drawing approval guide covers that step.
If your team is short on drafting capacity, our rooftop detailed engineering team prepares these packages for EPCs.
How does Tamil Nadu compare with other states?
Every state sets its own rules through its regulator. Tamil Nadu stands out for charging network fees on generated units and for splitting domestic and non-domestic routes. Our state-by-state DISCOM net metering process shows how others handle it. For what changed in 2026, including Tamil Nadu’s draft rules, see our DISCOM net metering changes tracker.
FAQ
Does Tamil Nadu still allow net metering?
Yes, for domestic consumers, up to their sanctioned load. Other LT consumers use net feed-in instead, where exports earn a feed-in tariff rather than offsetting units.
What is the maximum rooftop solar size in Tamil Nadu?
The 2019 policy caps consumer systems at 100% of sanctioned load. Net feed-in also stops at 999 kW. Transformer headroom can set a lower practical limit.
Are network charges applied to self-consumed solar?
Yes. Under the 2021 order they apply to total generation for net metering and net feed-in consumers. Domestic consumers pay a reduced share.
Is there a new Tamil Nadu solar policy for 2026?
We found no newer notified solar policy as of October 2026. Check the Energy Department and TNERC sites, since a new policy or regulation would change these rules.
Next step
Tamil Nadu rewards designs sized to daytime load and documented against the current TNERC order. If you want a second set of eyes on a TNPDCL file, send us the project details. We reply within one business day.