TNEB net metering and net feed-in
Most people picture net metering as units out cancelling units in. For a household in Tamil Nadu that is broadly right. For most commercial applicants since 25 March 2019 it is not — they are on net feed-in, where exported units are bought from you rather than offset against what you use later. The difference changes what size of system is worth building, which is why it is the first thing we establish. Checked 14 October 2026.
Capacity limits are as set out in the state regulations. Note particularly that 150 kW is the point above which gross metering applies — it is not, as is often written, a ceiling on net metering.
Net metering
Units you export offset units you import, and the bill settles the difference. This is the arrangement most people picture when they say "net metering", and for a household it is still available.
Who it applies to: Domestic consumers. Capacity: Up to your sanctioned load.
Net feed-in
Exported units are bought from you at a rate the regulator sets, rather than cancelling out units you draw later. It is not one-for-one, and since 2019 it is what most new commercial applicants are on.
Who it applies to: Every category except agriculture. Capacity: Up to 999 kW.
Gross metering
The whole output goes to the grid and is paid for, and you buy everything you consume separately. Only relevant at larger sizes - and note that 150 kW is the point at which this starts, not a limit on anything else.
Who it applies to: Every category except domestic consumers and solar generators. Capacity: Above 150 kW, up to 999 kW.
What you get paid for an exported unit
We are not going to put a number here, and it is worth explaining why rather than just leaving a gap. The rate is set by order of the state regulator and it changes. The last generic tariff we can actually point at — ₹3.61 a unit for systems up to 10 kW, less for larger ones — ran until 31 March 2023 and is therefore not current. The figures on competing websites today disagree with one another by more than a rupee a unit, and none of them names the order it came from.
Ask TNPDCL for the rate currently in force before you build a payback calculation on it. If an installer quotes you a rate per exported unit, ask which order it comes from — the answer tells you a great deal about the rest of the quotation.
Why this decides your system size
Here is the practical consequence, and it is the reason this page exists. An exported unit almost always pays you less than a consumed unit saves you. So the system worth building is the one sized against what you actually use while the sun is up — not the one that fills the available roof.
Oversizing converts an asset into a low-paid exporter. It is also the easiest way for an installer to sell a larger job, which is why you will sometimes see a quote that quietly assumes every surplus unit earns the retail tariff. Twelve months of your own bills settle the question properly, and that is what our savings calculator and the site survey work from.
What the application needs
- A copy of a recent electricity bill, for the service connection the system will feed
- Proof of ownership or occupancy of the premises
- The technical particulars of the system - panel and inverter make, model and rating
- A single-line diagram of the installation
- Identity proof of the consumer named on the connection
- The signed application form itself, which we complete and file for you
We prepare and file this as part of the installation, from Sankagiri, along with the commissioning paperwork once the meter is fitted. Sanction typically takes 60 to 120 days from submission — the one part of a solar project nobody can accelerate, and we would rather say so at the start than apologise for it at week ten.
Common questions
Do my exported units cancel out the units I use at night?
For a household on net metering, broadly yes - exports offset imports and you pay the difference. For most commercial applicants since March 2019 it is net feed-in instead, where exported units are bought from you at a set rate rather than cancelling out what you draw later. Which one applies to you is the first thing to establish, because it changes what size of system makes sense.
What will I be paid per unit I export?
A rate set by TNERC order, and we will not quote you a number here that we cannot source. The last generic tariff we can point at ran to 31 March 2023, and the figures circulating on installer websites today disagree with each other by more than a rupee. Ask TNPDCL for the rate currently in force before you build a payback calculation on it - and be wary of anyone who quotes one without naming the order.
Is there a 10 kW limit on rooftop solar?
Not in the regulations. Ten kilowatts is a ceiling in the central subsidy scheme for residential systems, which is a different thing. Under the state regulations a domestic consumer can net up to their sanctioned load, and net feed-in runs to 999 kW. If your sanctioned load supports more than 10 kW, the rules do not stop you.
How long does the application take?
Typically 60 to 120 days from submission to sanction, and it is the part of a solar project nobody can speed up. We prepare and file it as part of the installation, which removes the back-and-forth but not the waiting. Anyone promising a faster sanction is promising something outside their control.
Should I just build the biggest system my roof takes?
Usually no, and this is where the mechanism matters most. If an exported unit pays you less than a consumed unit saves you - which is the normal situation - then the system worth building is the one sized against what you actually use during daylight, not the one that fills the roof. Oversizing turns an asset into a low-paid exporter.
Are there charges on top?
Network charges apply to rooftop solar consumers and are set separately from the export rate, with smaller domestic systems paying a reduced proportion. They are modest relative to the saving, but they belong in an honest calculation, and a quote that shows a payback period without them is showing you the optimistic version.
Where this comes from
- TNERC - Grid Interactive Solar PV Energy Generating Systems Regulations, 2021
- TNPDCL unified solar rooftop portal - applications and net metering
Regulations and tariffs change by order. This page was last checked on 14 October 2026. If you are reading it much later, confirm the current position before relying on it — or ring +91 7871631474 and we will tell you where things stand this week.
Find out which arrangement you would be on
It depends on your connection category and when you apply, and it determines the system size worth installing. A survey answers it from your own bills rather than from a rule of thumb.
We file the net-metering application as part of the installation.