Net metering lets a bi-directional meter credit the solar units you export against what you draw. In Kerala, KSERC's 2025 regulations reportedly keep net metering for small systems (about 1–3 kW, or up to 5 kW with a battery) and use net billing for larger ones, where exports are settled at a low rate. Kanyakumari follows TNPDCL and TNERC rules. Size your system to your daytime use and confirm current limits with your section office.
What net metering means
A bi-directional meter records what you draw from the grid and what your solar sends back. Surplus units are credited against your consumption and reduce your bill. Fixed charges and duty remain, so the bill rarely reaches exactly zero. Terms are explained in the glossary.
Kerala: net metering versus net billing
KSERC's renewable energy regulations (effective late 2025, billing changes from 2026) are reported to separate small systems under net metering from larger systems under net billing. With net billing you buy units at the retail tariff and exports are settled at a low rate (reports put it around ₹2.8–3.1 per unit). Time-of-day pricing and grid-support charges for larger systems have also been reported. Existing net-metered owners are reported to keep their original terms. These details come from trade reports; confirm with your KSEB section office. See the KSEB application guide.
Tamil Nadu and Kanyakumari: TNPDCL
Grid connection and net metering in Kanyakumari follow TNPDCL and TNERC procedures. The state also gives free units to domestic consumers and has announced a ₹22,000 solar top-up. See the TNPDCL guide.
The application process
- Apply for feasibility with KSEB or TNPDCL.
- Sign the agreement and pay fees.
- Install through a registered vendor (do not energise yet).
- Inspection of earthing, protection and anti-islanding.
- Bi-directional meter installed and commissioning.
Meter delays
Installers reported delays in net-meter supply in parts of Kerala in August and September 2026. Keep the application number, ask the section office for dates and get your installer to state in writing who follows up. Read what to do if your net meter is late.
How to size for the rules
Under net billing, oversizing for export earns far less than the units you avoid buying. Size for your daytime use, shift loads such as EV charging and water heating to daytime, and use the calculator, which shows the net-metered option alongside the zero-bill option for Kerala.
Metering terms in plain words
| Term | Meaning |
|---|---|
| Net metering | One-for-one credit: units you export offset units you import. |
| Net billing | You pay retail for imports; exports are paid at a set (lower) rate. |
| Gross metering | All generation is sold to the utility at a tariff; you buy all your power separately. |
| Banking | Carrying surplus credit forward to later billing periods. |
| APPC | Average power purchase cost, the rate used to settle some exports. |
| Anti-islanding | Inverter protection that stops exporting when the grid is down. |
Illustration: how size changes the Kerala outcome
Take a home using about 480 units a month on a ₹3,500 monthly bill. Our calculator's illustrative model, which assumes the reported rules, gives two options.
| 3 kW (net metering) | 5 kW (net billing) | |
|---|---|---|
| Net cost after ₹78,000 subsidy | ~₹1.1 lakh | ~₹2.1 lakh |
| Bill reduction | ~73% | ~100% of energy charges |
| Payback | ~3.5 years | ~5.3 years |
The 3 kW option is the better investment per rupee; the 5 kW option is for those who want the bill near zero. Which is right depends on the rules in force when you apply. Model yours in the calculator.
Time-of-day pricing: shifting your loads
- Run the washing machine, water pump and geyser during the day.
- Schedule EV charging in sunlight hours where possible; see solar + EV.
- Pre-cool rooms in the afternoon rather than running AC hard at night.
- Use timers on pumps and water heaters.
Under net billing, units you use yourself during the day are worth the full tariff, while exports earn little.
Tamil Nadu: free units and net metering together
If TNPDCL gives your household the first 100 units free each bimonthly bill, solar helps only on units beyond that. A household using 400 units a month (800 per bill) has about 700 billable units per bill, so solar sized to roughly 350 units a month covers the billable part. A household using 150 units a month has far fewer billable units and a longer payback. The calculator applies this when you pick Kanyakumari. Always check the current TNERC tariff order.
Timeline: feasibility to commissioning
| Step | What to do | Typical wait |
|---|---|---|
| Feasibility | Apply online or at the section office | 2 weeks (reported 15-day target in Kerala) |
| Agreement | Sign and pay fees | Days |
| Installation | Registered vendor installs; do not energise | 1–3 days |
| Inspection | DISCOM checks earthing and protection | 1–3 weeks |
| Meter and commissioning | Bi-directional meter installed | 2–6 weeks, delays reported |
Checklist before you sign
- Which metering route will my size fall under, and what is the export rate?
- Who applies, who pays the fees, and who follows up the meter?
- What happens to my payment if the meter is late?
- Is my sanctioned load enough?
- Do I keep my current terms if I add capacity later?
Questions people ask at the section office
- What is my application number and its current status?
- Is a three-phase meter available now?
- Which documents are still pending?
- When is inspection scheduled?
Keep screenshots and dates. If delay drags on, read what to do if your net meter is late.
On-grid, hybrid and outages
On-grid systems switch off during a power cut. If you need backup, choose a hybrid inverter with a battery; see on-grid vs hybrid.
Sources and how we maintain this page
Reviewed on 2026-10-03 and re-checked monthly or when a rule changes. Where a figure comes from news or trade reports, the page says so.
- SolarQuarter: KSERC renewable energy regulations
- GSL Energy: KSEB net meter delay (installer report)
- PM Surya Ghar national portal
- KSERC
- TNPDCL / TNEB
