Net Metering in Tamil Nadu: How It Works
How the bi-directional meter adjusts your TNPDCL bill, what happens to the units you export, and how to apply for a net meter step by step.
Rainbow Solar Energy Team
7 min read
Updated
In this article
Key takeaways
- A net meter (bi-directional meter) records units you take from the grid and units your panels send to it.
- Your TNPDCL bill charges only the net units: import minus export.
- Surplus units roll forward; any balance at the end of the settlement period is settled at a rate fixed by the regulator.
- Net metering is required for the PM Surya Ghar subsidy, and Rainbow Solar files the application for you.
Net metering is what makes on-grid rooftop solar so affordable: instead of storing daytime power in expensive batteries, you “store” it in the grid and take it back at night. Here is exactly how it works in Tamil Nadu.
How net metering works
- DaytimeYour panels power the home. Units you don't use flow to the grid and the net meter counts them as export.
- Night and cloudy hoursYou draw power from the grid as usual. The meter counts these units as import.
- BillingEvery two months, TNPDCL bills you only for import minus export. If export is higher, the surplus is carried forward.
- SettlementSurplus units left at the end of the settlement period are settled as per TNERC rules.
An example bill
| Units (2-month cycle) | |
|---|---|
| Units drawn from the grid (import) | 620 |
| Units sent to the grid (export) | 540 |
| Net units billed | 80 |
With a 3 kW system in Tamil Nadu. Because only 80 units are billed, they fall in the free first 100 units of the domestic tariff, so the energy charge can drop to zero.
This is also why solar savings in Tamil Nadu are bigger than they look: removing units from the bill pushes you out of the expensive top slabs. Our calculator works this out using the actual TNPDCL slabs.
Who can get a net meter?
- Domestic, housing society (common services), commercial and other eligible consumers with a valid TNPDCL connection.
- The solar capacity must be within the limits allowed for your sanctioned load and the local transformer.
- The system must use approved equipment and be installed by a registered vendor (for subsidy cases).
Commercial and industrial consumers may come under different metering arrangements. We check what applies to your connection during the survey.
How to apply for a net meter
- ApplicationApply through the PM Surya Ghar national portal (homes) or the TNPDCL rooftop solar process, with your consumer number.
- FeasibilityTNPDCL checks your connection and the local transformer capacity.
- InstallationYour vendor installs the system with the required safety equipment.
- Inspection and meterTNPDCL inspects the system and replaces your meter with a bi-directional net meter.
- CommissioningThe system is commissioned, and for homes the subsidy claim is completed.
We handle the net meter for you
Application, inspection, meter and subsidy: one team, start to finish.
Timelines and charges
The net meter process usually takes 2–5 weeks after installation, depending on your area. TNPDCL may charge application, meter and testing fees as per its schedule; your Rainbow Solar quote includes the paperwork so there are no surprises. See the full subsidy process in our PM Surya Ghar guide for Tamil Nadu.
Does net metering work during a power cut?
No. On-grid systems switch off during outages for line workers' safety. If you want power during cuts, you need a hybrid system with a battery.
Written by our solar engineers and subsidy specialists, who design and install rooftop systems for homes, societies and businesses across Tamil Nadu. Figures are indicative and reviewed regularly; your free site survey gives exact numbers for your roof.
