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Introduction

Net metering is one of the most important concepts to understand before installing a grid-connected rooftop solar system. Instead of treating solar as an isolated power plant, net metering connects the PV system to the consumer’s electrical installation so that solar generation can offset electricity consumed from the grid, subject to the applicable rules and meter arrangement.

The exact process is not identical across India. The consumer category, sanctioned load, system capacity, DISCOM procedures, state regulations, metering framework and technical requirements can affect eligibility, approvals and settlement of electricity. A national rule or guideline should therefore be treated as a framework, not as a substitute for the current rules of the relevant electricity distribution licensee.

This guide explains how net metering works, how to size a rooftop system, what the application process normally involves, how billing can change, and what residential and commercial consumers should verify before signing an EPC contract.

1. What Is Net Metering?

In a basic grid-connected rooftop solar arrangement, the solar plant supplies electricity to the consumer’s internal loads. When solar generation is lower than the site’s demand, electricity is imported from the grid. When generation exceeds the instantaneous demand, surplus electricity may flow to the grid, subject to the approved metering and settlement arrangement.

A bidirectional meter records the relevant import and export quantities under the applicable metering framework. The electricity bill is then calculated according to the settlement mechanism prescribed by the competent authority and DISCOM.

Situation
Situation	Typical power flow
Solar generation < site load	Solar serves part of the load; remaining demand is imported from grid.
Solar generation = site load	Solar generation approximately matches instantaneous demand.
Solar generation > site load	Surplus may be exported through the approved metering arrangement.
Grid outage	A conventional grid-tied inverter normally shuts down for anti-islanding protection unless the system has an appropriately designed backup/hybrid architecture.

2. Net Metering vs Gross Metering

Feature	Net metering	Gross metering
Primary concept	Solar mainly offsets consumer consumption; surplus is settled under applicable rules.	Solar generation is measured separately and compensated/settled under the applicable framework.
Consumer objective	Reduce purchased grid electricity.	Export/settle generated electricity under the applicable tariff or compensation mechanism.
Important variable	Self-consumption and import/export settlement.	Applicable generation compensation rate and contract terms.
Best approach	Depends on consumer profile and current DISCOM rules.	Depends on state framework and project structure.

Terminology and availability of these mechanisms can vary by state and consumer category. Always confirm the currently applicable DISCOM/regulatory framework before making an investment decision.

3. What Does the National Framework Say?

The Electricity (Rights of Consumers) Rules, 2020 and subsequent amendments established consumer-service provisions and included provisions relevant to rooftop solar metering. A Central Electricity Authority publication notes that an amendment notified in September 2021 increased the net-metering limit from 10 kW to 500 kW. However, the practical approval and implementation conditions for a particular consumer still need to be checked against the current state/DISCOM framework.

The Ministry of New and Renewable Energy’s rooftop-solar portal provides resources covering standards for grid interconnection, rooftop-solar specifications, preliminary assessment and DISCOM information.

These national resources are useful starting points, but a project should not be approved or purchased solely on the assumption that a national capacity limit guarantees eligibility at a specific premises.

4. Who Can Use Net Metering?

Eligibility depends on the applicable electricity regulations and DISCOM procedure. Residential rooftop solar is the most visible use case, but commercial, institutional and other consumer categories may also have grid-connected rooftop options depending on state rules.

Identify the electricity consumer category shown on the bill.
Check the current DISCOM rooftop-solar and metering procedure.
Confirm sanctioned load/contract demand and any system-capacity limits.
Confirm whether the proposed plant can be connected at the existing supply voltage.
Check whether special approval is needed for larger systems or particular consumer categories.
Obtain written feasibility/approval where required before committing to installation.

5. Residential Net Metering

For a home, the economic model is usually driven by how much daytime solar generation offsets household electricity use and how surplus energy is settled. The system should be sized from actual annual consumption and roof feasibility rather than simply choosing the largest possible plant.

PM-Surya Ghar: Muft Bijli Yojana is a residential rooftop-solar scheme. The official sanction describes a total outlay of ₹75,021 crore and CFA for eligible residential consumers, with the published structure providing 60% of benchmark cost for the first 2 kW, 40% for an additional 1 kW, and no additional CFA beyond 3 kW; GHS/RWA common facilities including EV charging have separate provisions.

The residential subsidy/CFA is not the same thing as net-metering eligibility. A consumer should treat subsidy eligibility and grid-interconnection approval as separate checks.

6. Commercial Net Metering

Commercial consumers should begin with their tariff, annual consumption, daytime load and the current DISCOM rules. A commercial plant may have a strong self-consumption case even when export treatment is less attractive than direct consumption.

Analyze monthly and interval consumption.
Separate energy charges from demand and fixed charges.
Check sanctioned load and maximum demand.
Confirm the permissible rooftop-solar capacity.
Review export settlement rules and applicable metering charges.
Assess transformer, switchgear, protection and cable capacity.
Compare self-consumption-focused sizing with larger systems that depend on export.

7. How to Size a Net-Metered Solar System

A preliminary sizing formula is:

PV capacity (kW) ≈ Annual electricity consumption (kWh) × desired annual solar share ÷ site-specific solar yield (kWh/kW/year).

Example: a commercial building consumes 600,000 kWh/year. If the planning target is 40% solar contribution and the preliminary specific-yield assumption is 1,400 kWh/kW/year:

600,000 × 0.40 ÷ 1,400 ≈ 171 kW.

This does not mean 171 kW is automatically the approved or optimal system. The result must be checked against daytime load, roof area, shading, sanctioned load, interconnection rules, transformer capacity and export settlement.

8. Why Daytime Load Matters

Two buildings with identical annual electricity consumption can have very different solar economics. A factory operating through daylight hours may directly consume a large share of its solar generation. An office that is lightly occupied on weekends may have a different export pattern.

Load pattern	Net-metering design implication
High daytime load	More PV generation can be directly self-consumed.
Low daytime load	A larger portion may become surplus export.
Strong weekend variation	Monthly/interval analysis becomes important.
Seasonal production	Monthly generation and consumption should be compared.
24-hour operation	Solar can offset daytime demand while night demand remains grid-supplied.

9. Roof Area and Solar Capacity

Net-metering eligibility does not remove physical design constraints. The proposed capacity must fit safely on the available site.

Measure usable roof area rather than total roof area.
Account for shading and obstructions.
Maintain access for maintenance and emergencies.
Check structural capacity and mounting loads.
Protect waterproofing and drainage.
Plan inverter, cable and protection locations.
Use the actual module dimensions when preparing the layout.

10. Electrical Design for Net Metering

The solar plant connects to the consumer’s electrical system through a defined point of interconnection. The electrical design should be coordinated with the existing installation and the DISCOM’s technical requirements.

Solar PV modules and mounting structure.
DC cables, connectors and DC protection as applicable.
String/central inverters according to project architecture.
AC isolation and protection.
AC cabling and interconnection equipment.
Surge protection and earthing as required.
Bidirectional/net meter or other approved metering arrangement.
Protection and anti-islanding functions.
Monitoring and generation metering where required.

For larger systems, the engineer may need to evaluate fault levels, transformer loading, protection coordination, voltage rise and power-quality conditions.

11. Transformer and Sanctioned-Load Check

A common mistake is to treat the roof as the only constraint. The electrical supply arrangement can be equally important.

Check transformer rating and present loading.
Check sanctioned/contract demand.
Review main-panel busbar and breaker capacity.
Confirm the proposed interconnection voltage.
Assess cable routes and voltage drop.
Review reverse-power/export protection requirements where applicable.
Confirm the utility’s technical-feasibility process.

12. Net Metering Application Process

The exact workflow differs by DISCOM, but a typical project sequence is:

Step	Typical action
1. Consumer eligibility check	Review consumer category, tariff, sanctioned load and applicable rules.
2. Site survey	Assess roof, shading, structure and electrical system.
3. Preliminary design	Prepare capacity, layout and single-line diagram.
4. Application	Submit the rooftop-solar/net-metering application through the applicable portal/process.
5. Technical feasibility	DISCOM evaluates the proposed interconnection under its rules.
6. Approval / agreement	Complete required approvals, agreements and payments where applicable.
7. Installation	Install the approved system using the specified technical requirements.
8. Inspection / commissioning	DISCOM or authorized personnel inspect and complete the applicable process.
9. Metering	Install/replace/configure the approved meter and associated equipment.
10. Synchronization	Connect the system to the grid after required approvals are complete.
11. Billing	Import/export or generation data is reflected according to the approved settlement mechanism.

Do not treat an EPC quotation as proof of utility approval. Approval is a separate regulatory/technical step.

13. Documents Commonly Requested

Latest electricity bill.
Consumer/account identification documents.
Site ownership/authorization documents where required.
Solar system specification.
Single-line diagram.
Module and inverter technical information.
Structural documents where applicable.
Electrical safety/protection details.
Application forms and declarations prescribed by the DISCOM.
Testing/commissioning documentation where required.

The exact document list should be taken from the current DISCOM procedure.

14. How Net Metering Changes the Electricity Bill

A simple example illustrates the concept. Assume a building consumes 1,000 kWh during a billing period and the solar plant generates 800 kWh. If 650 kWh is consumed directly at the premises and 150 kWh is exported, the remaining grid import would be approximately 350 kWh before accounting for the precise meter-settlement rules.

The final bill is not necessarily equal to 350 kWh multiplied by the headline tariff. Fixed charges, demand charges, taxes, time-of-day components and the applicable treatment of export can remain relevant.

15. Self-Consumption vs Export

Generation outcome	Economic interpretation
Directly self-consumed solar	Usually offsets electricity that the consumer would otherwise purchase, subject to tariff structure.
Exported surplus	Value depends on the applicable settlement/compensation mechanism.
Unused roof capacity	May be preferable to oversizing if export is restricted or less valuable.
Battery-stored solar	Can shift energy to later hours but adds capital cost and replacement considerations.

The correct system size is therefore an optimization problem, not simply a maximum-capacity exercise.

16. Net Metering and Batteries

A standard net-metered system may not need a battery. Batteries become relevant when the consumer needs backup, load shifting, peak management or greater control over solar energy.

Backup for critical loads.
Evening load shifting.
Reducing generator runtime.
Managing specific peak-demand patterns.
Improving resilience where outages materially affect operations.

A battery should be evaluated on its own kW, kWh, cycle life, efficiency, warranty, replacement and operating requirements. Do not add battery capacity simply because a solar quotation includes it.

17. Net Metering and Diesel Generators

Businesses with DG backup need a coordinated control philosophy. A grid-connected inverter normally uses anti-islanding protection and should not be assumed to energize a dead utility grid.

Define grid-present and grid-absent operating modes.
Coordinate solar inverter and DG controls.
Check generator loading and reverse-power considerations.
Review automatic changeover/AMF logic.
Determine whether a hybrid inverter or controller is required for the intended backup operation.

18. Net Metering for Apartments and Housing Societies

Apartment projects can involve individual residential meters, common-area meters, or group/virtual metering structures depending on local rules. The physical solar plant may be installed on a shared roof, while the electricity benefit is allocated according to the approved arrangement.

MNRE rooftop-solar resources include material on group and virtual net metering, and MNRE has published a clarification on CFA applicability under virtual-net-metering arrangements.

Because rules and implementation can differ by state and DISCOM, a housing society should obtain the current local procedure before choosing an allocation model.

19. Net Metering for Schools, Hospitals and Institutions

Institutional consumers should evaluate operating hours, critical loads, backup requirements and the consumer category shown on the electricity connection.

Separate critical and non-critical loads.
Analyze daytime occupancy.
Review DG and emergency-power arrangements.
Check sanctioned load and transformer capacity.
Confirm the applicable institutional/commercial metering framework.
Plan installation around the institution’s operations and safety requirements.

20. Net Metering for Factories and Manufacturing Units

Industrial consumers often have substantial daytime demand, which can make self-consumption an important design factor. The audit should include production shifts, motors, compressors, pumps, HVAC and process equipment.

Analyze interval data.
Check maximum demand and power factor.
Review transformer loading.
Assess harmonics and power-quality conditions.
Coordinate solar with DG and critical production loads.
Compare rooftop, ground-mounted and carport options if roof area is limited.

21. Net Metering vs Open Access

Rooftop net metering and open-access renewable procurement are different project structures. Net metering generally concerns generation at or associated with the consumer premises and settlement through the applicable distribution/metering framework. Open access can involve electricity procurement from a separate generating source and additional regulatory, scheduling and network-charge considerations.

A business considering a large off-site renewable project should not treat it as simply a larger rooftop net-metering installation.

22. Costs to Consider

The net-metering application itself is only one part of project economics. A complete budget can include:

PV modules.
Inverters.
Mounting structure.
DC/AC cables and protection.
Electrical panels and interconnection equipment.
Metering and utility-related charges where applicable.
Structural/civil work.
Monitoring and communications.
Engineering and documentation.
Installation and commissioning.
Testing and approvals.
O&M and future component replacement.

The exact cost varies with system size, roof type, electrical voltage, mounting complexity, equipment selection and local conditions.

23. How to Calculate Solar Savings

A simplified calculation is:

Annual savings ≈ Solar energy self-consumed × avoided electricity value + applicable value of exported energy − operating costs.

Example: a 200 kW plant is assumed to generate 280,000 kWh/year. If 85% is self-consumed, 238,000 kWh is directly used. At an illustrative avoided energy value of ₹8/kWh, the direct energy-value component is ₹19.04 lakh/year. The remaining export should be valued under the actual applicable settlement mechanism, and O&M, degradation and other costs should then be included.

24. Payback Period

Simple payback = Net project investment ÷ first-year net annual savings.

For a serious business case, also examine NPV and IRR. The model should include degradation, O&M, financing, tariff assumptions, replacement costs and the applicable export settlement.

Avoid comparing two projects only by ₹/kW. A lower EPC price can have a different generation estimate, equipment scope, warranty, O&M package or electrical scope.

25. Common Net-Metering Problems

Application submitted under the wrong consumer category.
Solar capacity proposed without checking sanctioned load or DISCOM limits.
Roof capacity assumed without structural verification.
Export assumptions copied from another state.
Residential subsidy assumed for a commercial consumer.
Metering requirements discovered only after installation.
DG and solar controls not coordinated.
Insufficient protection or earthing planning.
Electrical panel or transformer constraints overlooked.
Installer promises a fixed bill reduction without analyzing actual tariff and load profile.

26. Net-Metering Checklist Before Signing an EPC Contract

Item	Confirm
Consumer category and tariff	☐
Current DISCOM net-metering eligibility	☐
Permitted system capacity	☐
Sanctioned/contract demand	☐
Roof/site feasibility	☐
Structural assessment	☐
Electrical interconnection point	☐
Transformer/panel capacity	☐
Generation estimate and assumptions	☐
Self-consumption/export assumptions	☐
Metering/utility scope	☐
Approvals and documentation	☐
DG integration	☐
Warranty and O&M scope	☐
Financial model/payback	☐

27. 2026 Regulatory and Quality Considerations

Regulatory requirements can change, so current official documents should be checked immediately before procurement and commissioning. MNRE’s ALMM page currently states that listed PV module models/manufacturers are eligible for specified categories of projects including net-metering projects, and the page shows updates issued in 2026.

MNRE also published a 2026 notice concerning compliance with guidelines for inverter-level generation data and storage for rooftop solar systems. This reinforces the importance of checking current technical and data requirements rather than relying on an old project specification.

The exact applicability of any procurement or compliance requirement should be checked against the project’s consumer category, commissioning date, scheme and current official orders.

28. Practical Example – 50 kW Commercial Rooftop

Assumption	Illustrative value
PV capacity	50 kW
Specific yield	1,400 kWh/kW/year
Estimated annual generation	70,000 kWh
Self-consumption	90%
Directly self-consumed energy	63,000 kWh
Illustrative avoided energy value	₹8/kWh
Direct energy-value savings	₹5.04 lakh/year before O&M, degradation and other adjustments

This is an illustrative engineering/financial example. Actual generation and savings should be modeled from the site’s irradiation, orientation, shading, load profile, tariff and applicable metering rules.

29. Frequently Asked Questions

Is net metering the same in every Indian state?

No. National rules provide an important framework, but state regulations, DISCOM procedures, consumer categories and metering arrangements can differ.

Can a commercial building use net metering?

Potentially, subject to the applicable state/DISCOM rules, consumer category, sanctioned load, system capacity and technical feasibility.

Is 500 kW automatically allowed for every rooftop?

No. A national framework reference to a 500 kW net-metering limit does not mean every consumer can install 500 kW. Local eligibility and technical conditions still need to be checked.

Does net metering mean the electricity bill becomes zero?

Not necessarily. Fixed charges, demand charges, taxes, minimum charges and other tariff components may remain, and export settlement rules matter.

Do I need a battery with net metering?

Usually not for basic grid-connected bill reduction. Batteries are mainly considered for backup, shifting or resilience requirements.

What happens to solar power during a grid outage?

A conventional grid-tied inverter normally shuts down for anti-islanding safety. Backup operation requires a suitable hybrid/storage architecture.

Can I increase my solar plant later?

Possibly, but the expanded system must satisfy the then-current utility, technical and structural requirements.

Does PM-Surya Ghar subsidy apply to commercial buildings?

The PM-Surya Ghar CFA described by MNRE is for eligible residential consumers. Commercial consumers should not assume residential CFA applies.

How long does net-metering approval take?

There is no single nationwide timeline that applies to every project. The current DISCOM process and application volume determine the actual timeline.

What should I ask an EPC company?

Ask for the proposed capacity, generation model, equipment specifications, single-line diagram, utility scope, approvals, metering responsibility, warranties, O&M and clearly stated financial assumptions.

30. How SSREALTECH Can Help

SSREALTECH can help businesses and property owners with rooftop-solar feasibility, electricity-data analysis, preliminary capacity sizing, electrical coordination, EPC planning, installation, commissioning support and O&M. Net-metering projects should be designed around the consumer’s actual bill, load profile, site conditions and current DISCOM requirements.

For solar feasibility and net-metering guidance, contact SSREALTECH: 9993070355

31. Official Reference Sources

Ministry of New and Renewable Energy – Grid Connected Rooftop Solar Programme: https://mnre.gov.in/en/grid-connected-solar-rooftop-programme/

MNRE National Portal for Rooftop Solar: https://solarrooftop.pmsuryaghar.gov.in/

PM-Surya Ghar sanction order: https://solarrooftop.pmsuryaghar.gov.in/notification/170_notification.pdf

MNRE ALMM – Approved List of Models and Manufacturers: https://mnre.gov.in/en/approved-list-of-models-and-manufacturers-almm/

Central Electricity Authority: https://cea.nic.in/

Before procurement, verify the latest state electricity regulatory commission and DISCOM order/procedure applicable to the specific consumer and site.

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Conclusion

Net metering can materially change the economics of a grid-connected rooftop solar project because it connects solar generation with the consumer’s electricity account and the applicable export-settlement mechanism. The right system size depends on more than roof area: electricity consumption, daytime demand, tariff, sanctioned load, utility rules, electrical infrastructure, structural feasibility and export treatment all matter.

Before installation, verify the current DISCOM process, prepare a transparent generation and savings model, and ensure that the EPC scope includes the technical and documentation requirements needed for commissioning. A well-designed net-metered solar system starts with accurate data and ends with a clear, approved interconnection plan.

Solar Net Metering in India – Complete Residential & Commercial Guide