📖 Understanding Import and Export of Solar Energy in TNEB's Bimontly Billing - Residencial Tariff 🏠

Newera Renewables
Jul 22
3 min read

Updated: Aug 11

As solar adoption grows across Tamil Nadu, many consumers are installing rooftop solar systems and connecting them to the grid under the Tamil Nadu Electricity Board (TNEB)’s net metering scheme. If you're a solar consumer—or planning to become one—it's important to understand how your import and export of electricity is calculated in TNEB’s bimonthly billing cycle.

This blog breaks it down clearly.

☀️ What is Net Metering?

Under TNEB's net metering policy:

Import is the electricity you consume from the grid when your solar system isn't generating enough.
Export is the excess solar power your system sends back to the grid when it generates more than you need.

A bi-directional meter installed by TNEB tracks both these values.

📊 How Import & Export Are Calculated in TNEB Bimonthly Billing

TNEB follows a bimonthly billing cycle, during which your net meter is read and your energy usage is calculated as follows:

🔹 Step 1: Meter Reading

TNEB reads the cumulative import and export values from your net meter. The difference from your previous readings gives the energy usage for the current cycle.

Example:

Import Reading (Current) = 3500 kWh
Import Reading (Last) = 3000 kWh
✅ Import Units = 500 kWh
Export Reading (Current) = 1200 kWh
Export Reading (Last) = 900 kWh
✅ Export Units = 300 kWh

🔹 Step 2: Net Unit Calculation

Net Energy = Import – Export

In this case:Net Units = 500 – 300 = 200 kWh

This net usage is what appears on your TNEB bill.

🧾 Billing Scenarios

✅ Scenario A: Import > Export (Net Consumer)

You used more electricity than your solar system exported.

👉 You pay for the net units consumed (e.g., 200 kWh).

✅ Scenario B: Export > Import (Net Exporter)

You generated more electricity than you consumed.

👉 The excess units are carried forward as credit to future bills.

💡 What Happens to Extra Solar Credits?

Surplus units are carried forward to the next billing cycle.
They can be adjusted against future consumption.
At the end of the financial year, unused credits may lapse—they are not paid out in cash.

💰 Charges That Still Apply

Even if you have surplus solar credits, some charges are always applicable, such as:

🔌 Fixed charges (based on your sanctioned load)
🔧 Net-Metering and service charges
🧾 Electricity tax/duties (if applicable)

📱 How to Check Your TNEB Solar Bill

You can view your bimonthly bill and solar adjustments online:

Go to https://www.tnebnet.org/awp/login
Enter your Service Number
View or download the bill and check:
- Import units
- Export units
- Net units billed
- Carried forward credits (if any)

🧾 Summary Table

Component	Description
Import	Power consumed from grid
Export	Solar power sent back to grid
Net Units	Import – Export
Credits	Export > Import → Carried forward
Fixed Charges	Always applicable
Billing Cycle	Every 2 months (bimonthly)

🛠 Need Help With Tariff or Setup?

If you’re a residential, commercial, or industrial user, your billing may differ slightly based on your tariff category. Get in touch with Newera Renewables, your trusted Solar Installer for personalized guidance—or feel free to contact us for a breakdown based on your service type.