Net Metering vs Net Billing: What Maharashtra’s New Rules Could Mean for TN & Kerala Solar Owners

“Wait, my neighbour in Pune says his solar bill credits just changed overnight. Could that happen to my KSEB connection too?”

That’s the message a Kochi homeowner sent us last week, and it’s a fair question. When a big state like Maharashtra rewrites its rooftop solar billing rules, solar owners in Tamil Nadu and Kerala start wondering if they’re next.

Maharashtra’s regulator recently reshaped how rooftop solar exports are billed, and the change has put two terms net metering and net billing back in every solar owner’s search bar. If you’re in Tamil Nadu tracking TANGEDCO, or in Kerala trying to run a proper net metering KSEB check before you sign an installation contract, this shift matters more than it might seem. 

We work with rooftop solar owners across South India every day, and we’ve broken down exactly what’s changing, what isn’t, and what you should actually do about it.

Net Metering vs Net Billing: The Core Difference

Before comparing states, it helps to get the basic mechanics right. These two billing models sound similar but behave very differently on your monthly bill.

Feature	Net Metering	Net Billing
How export is valued	At the same retail rate you pay for grid power	At a separate, usually lower, feed-in tariff
What gets recorded	One net figure (import minus export)	Import and export tracked and billed separately
Meter needed	Single bi-directional meter	Bi-directional meter, sometimes with separate import/export registers
Best suited for	Homes that consume most power in daytime or want simple bill offsetting	Utilities managing high solar penetration on the grid
Financial impact for owner	Generally higher savings	Generally lower savings, since export earns less than import costs

In short: net metering treats your exported units as equal in value to the units you draw from the grid. Net billing treats them as a separate, cheaper transaction. That difference alone can change your payback period by a year or more on an identical rooftop system.

MNRE SOLAR ROOFTOP SUBSIDY ENQUIRY

What Actually Changed in Maharashtra

Maharashtra’s regulator, MERC, revised several rooftop solar rules effective April 2026. Here’s the quick version:

• Net metering capacity raised to 5 MW (up from 1 MW), though your system still can’t exceed your sanctioned load.
• Grid support charges introduced above 10 kW. Systems up to 10 kW remain exempt.
• Deemed approval up to 10 kW under PM Surya Ghar, meaning no manual technical inspection is required for eligible applications.
• Time-of-Day billing now applies above 10 kW, which means exported daytime units can only offset consumption during solar hours not your evening peak usage.
• Annual settlement continues, with unused credits paid out at a lower rate (APPC) rather than retail value.

The direction is clear: as more rooftop solar connects to the grid, regulators are layering in conditions capacity slabs, time-based billing, and grid charges rather than removing net metering outright.

Why a Maharashtra Rule Change Matters If You Live in Chennai or Kochi

Electricity is a state subject in India, so TANGEDCO in Tamil Nadu and KSEB in Kerala don’t have to follow Maharashtra’s regulations. But regulators across states watch each other closely, and a pattern is emerging nationally:

• Capacity limits for automatic net metering are getting tighter, not looser
• Time-of-day and seasonal billing structures are being introduced where solar penetration is high
• Battery storage is increasingly nudged in, especially where evening peak demand doesn’t match solar generation hours

Kerala has already moved in this direction with its own 2025 regulatory update. Tamil Nadu hasn’t announced anything similar yet, but if you’re planning a system now, sizing it around today’s rules without checking what’s coming is a mistake we see often.

If you’re applying for a TANGEDCO net meter for the first time, we’ve laid out the full step-by-step process, documents, and common rejection reasons in our TANGEDCO net metering guide.

Where Tamil Nadu Stands Today

TANGEDCO’s current framework still defaults to net metering for LT (low-tension) consumers. A few practical points worth knowing:

• Single-phase domestic connections are generally capped at 10 kW; three-phase LT connections can go up to 75 kW, subject to feeder capacity at your local substation
• HT (high-tension) industrial and commercial consumers above certain thresholds may be moved to gross metering or a power purchase agreement structure instead
• Billing runs on a bi-monthly cycle, with surplus credits carried forward and any leftover balance settled annually at a buyback rate lower than the retail tariff
• As of mid-2026, most net metering applications still go through the local TANGEDCO sub-division office rather than a fully online portal

For a look at how commercial and industrial rooftop owners in the state are calculating payback under the current rules, our Tamil Nadu solar ROI breakdown is worth reading before you finalise a system size.

Where Kerala Stands: Net Metering KSEB, Explained Simply

This is the part most Kerala homeowners are actually searching for right now, so let’s answer it directly.

Is net metering still available through KSEB in 2026?
Yes. KSEB continues to offer net metering, but the rules changed under the new KSERC 2025 regulations, effective from January 1, 2026.

What’s the new capacity limit?
Domestic consumers can now avail net metering for systems up to 20 kW under the updated framework, though earlier commentary around the draft rules had suggested a much tighter cap for smaller residential systems. This is exactly why checking your specific eligibility before signing a contract matters generic numbers circulating online don’t always match what applies to your connection today.

How is billing calculated?
You’re billed only on the net units consumed (import minus export). Fixed charges, like meter rent, still apply regardless of how much you export. Any surplus at the end of the settlement year (March 31) is credited at a fixed per-unit rate rather than paid out at your retail tariff.

Does Kerala require battery storage now? Some of the regulatory discussion around the 2025 changes touches on grid stability measures, since Kerala’s peak demand falls in the evening while solar generation peaks at midday. Whether a battery is mandatory or simply advisable depends on your system size and connection category, so this is a detail to confirm directly rather than assume either way.

For the complete process from Annexure-A submission to meter commissioning our KSEB net metering step-by-step guide covers each stage in plain language.

How to Run a KSEB Solar Feasibility Check Before You Commit

Because Kerala’s rules have shifted more than once in the last year, running a proper feasibility check upfront saves you from resizing your system later. Here’s what that check should actually cover:

1. Confirm your sanctioned load against your KSEB bill your solar capacity can’t exceed it without a load enhancement application
2. Verify the current capacity slab applicable to your consumer category, since domestic and commercial limits differ
3. Check your roof’s shadow-free area a rough guide is 60–80 sq. ft. per kW of capacity
4. Ask your installer for the live KSERC 2025 position, not figures copied from an older landing page
5. Review the annual settlement rate so your savings estimate reflects actual credit value, not just gross generation
6. Confirm whether your system size or category triggers any storage or grid-charge requirement

A feasibility check isn’t a formality, it’s the difference between a system sized for today’s rules and one that needs costly rework in a year.

Net Metering vs Net Billing: Which Should You Actually Hope For?

If you get a choice, or if your state is debating a shift, here’s how to think about it:

• Net metering favours you if your household or business consumes a meaningful share of power during daylight hours, or if you value simple, predictable bill offsetting
• Net billing favours the grid operator more than the consumer, since it separates export value from import cost usually at a lower rate for what you send out
• A hybrid outcome (net metering below a capacity threshold, net billing or gross metering above it) is becoming the more common model across Indian states, including Maharashtra’s current structure

Neither model is inherently “bad” but net billing structurally reduces your savings compared to net metering for the same system, so knowing which one applies to your connection changes how you should size your rooftop array.

What Solar Owners in TN and Kerala Should Do Right Now

• If you already have solar, check your registration and net metering agreement status on your state’s official portal the ekiran portal for Kerala, or your local TANGEDCO office record for Tamil Nadu
• If you’re planning a new installation, get your feasibility assessed against the current regulation, not a general estimate
• Size your system around your actual consumption pattern and today’s capacity slab, not last year’s numbers
• Work with an installer who tracks regulatory updates as part of the design process, not just the installation

Whether you’re comparing net metering and net billing out of curiosity or actively running a KSEB solar feasibility check before an installation, the safest approach is the same: verify against the current regulation, size for your real consumption, and don’t let last year’s policy shape this year’s decision.

Rules will keep evolving as more homes and businesses go solar across South India. That’s expected, and it isn’t a reason to delay, it’s a reason to plan with current, verified information.

If you’re weighing a residential or commercial rooftop system in Tamil Nadu and want the sizing done around today’s TANGEDCO rules, our on-grid solar installation page walks through how we handle net metering paperwork and system design together.

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