How Does Net Metering Actually Reduce My Electricity Bill? A Simple Example

Net metering reduces your electricity bill by giving you credit for the surplus solar electricity that your rooftop system sends to the grid.

During sunny hours, your home first uses the electricity produced by the solar panels. Any extra electricity is exported to the grid. Later, when your solar system is not producing enough - such as at night - you import electricity from the grid. Under net metering, exported units are deducted from imported units for billing.

Send excess solar power to the grid, earn energy credits, and reduce your monthly electricity bill through net metering

In India, a bidirectional meter records electricity imported from and exported to the grid. The exact billing, credit carry-forward and settlement process is governed by the regulations of your State Electricity Regulatory Commission and DISCOM.

What Does a Net Meter Measure?

A net meter measures electricity flowing in two directions:

• Import units: Electricity taken from the grid.
• Export units: Surplus solar electricity supplied to the grid.

It does not directly measure all the electricity consumed inside your house.

For example, suppose your solar panels are generating 3 kW while your home is using 2 kW:

• 2 kW is consumed directly by your appliances.
• The remaining 1 kW is exported to the grid.

The 2 kW used directly does not pass through the net meter as an import or export. It reduces your bill immediately because you avoid purchasing those units from the DISCOM.

The Two Ways Solar Reduces Your Bill

1. Direct Solar Self-Consumption

Electricity generated and used immediately inside your home replaces electricity that you would otherwise purchase from the grid.

This is usually the most valuable use of solar power because each self-consumed unit avoids one full unit of grid electricity.

2. Credit for Exported Solar Units

When generation is higher than your household demand, the extra electricity flows into the grid.

The bidirectional meter records these exported units. Under net metering, they are adjusted against the units you import from the grid.

The basic calculation is:

Billable units = Grid import units − Solar export units

This calculation applies to energy units. Fixed charges, meter charges, electricity duty and other applicable items may still appear on the bill.

Net Metering Bill Calculation: A Practical Example

Consider a household with a rooftop solar system and the following monthly energy figures:

Monthly energy flow	Units
Total household electricity consumption	450 kWh
Total solar generation	360 kWh
Solar electricity used directly in the home	220 kWh
Surplus solar exported to the grid	140 kWh
Electricity imported from the grid	230 kWh

The energy figures balance correctly:

Household consumption = Self-consumed solar + Grid import

450 kWh = 220 kWh + 230 kWh

Solar generation also balances:

Solar generation = Self-consumed solar + Export

360 kWh = 220 kWh + 140 kWh

Step 1: Calculate Net Billable Units

The home imported 230 units and exported 140 units.

Net billable units = 230 − 140

Net billable units = 90 kWh

Although the house consumed 450 units during the month, the DISCOM charges the variable energy rate on only 90 net units in this simplified example.

Step 2: Calculate the Energy Charge

Assume an illustrative electricity rate of ₹7 per unit.

Without Rooftop Solar

450 units × ₹7 = ₹3,150

With Solar and Net Metering

90 units × ₹7 = ₹630

Energy-Charge Saving

₹3,150 − ₹630 = ₹2,520

The rooftop solar system reduces the energy charge from ₹3,150 to ₹630.

This example assumes exported units receive a one-for-one unit adjustment within the billing period. Your actual tariff slabs, duties and settlement rules may produce a different result.

Where Did the ₹2,520 Saving Come From?

The saving has two parts.

Saving From Direct Solar Use

The home directly consumed 220 solar units:

220 × ₹7 = ₹1,540 saved

Saving From Net-Metering Credits

The home exported 140 solar units, which offset 140 imported units:

140 × ₹7 = ₹980 saved

Total Energy Saving

₹1,540 + ₹980 = ₹2,520

This distinction is important. Net metering is responsible for the value of the exported units, while direct solar consumption reduces the number of units imported in the first place.

Why Is My Bill Not Zero Even When Solar Generation Is High?

A rooftop solar system can reduce the variable energy charge significantly, but the final electricity bill may still include:

Fixed or Demand Charges

Many electricity tariffs include a fixed monthly charge based on the sanctioned load, connection category or recorded demand. Solar generation generally does not remove this charge.

Meter and Service Charges

Meter rent, service charges or similar items may continue even when net energy consumption is low.

Electricity Duty and Other Levies

State-specific duties, taxes and surcharges may be calculated separately.

Minimum Billing Provisions

Some tariff categories have minimum monthly billing requirements.

Unadjusted or Expired Credits

Your DISCOM may carry excess export units forward to another billing period, settle them at the end of a financial year or compensate them at a rate specified by the state regulator.

Different Import and Export Valuation

Do not confuse net metering with net billing.

Under net metering, exported solar energy is deducted from imported grid energy in kWh. Under net billing, imported electricity and exported solar electricity can be valued at different tariffs. The Ministry of Power’s rules define these as separate billing mechanisms.

What Happens When Export Is Higher Than Import?

Suppose your meter records:

• Grid import: 180 units
• Solar export: 230 units

Your net position is:

180 − 230 = −50 units

You have exported 50 more units than you imported.

Depending on the applicable state and DISCOM regulations, these units may be:

• Carried forward to a future bill.
• Adjusted during a later settlement period.
• Purchased by the DISCOM at a specified rate.
• Subject to limits or expiry conditions.

Do not assume that every excess unit will be paid at your normal retail electricity tariff. Check the latest net-metering regulations and billing procedure applicable to your DISCOM.

How to Read a Solar Net-Metering Bill

Look for the following entries on your electricity bill:

• Import Reading: This is the electricity drawn from the grid during the billing period.
• Export Reading: This is the surplus solar electricity supplied to the grid.
• Net Energy: This is generally the difference between import and export units, subject to the DISCOM’s billing method.
• Previous Solar Credit: Some bills show unused export credits carried forward from earlier months.
• Current Credit Balance: This is the remaining solar credit after the current bill adjustment.
• Fixed Charges and Duties: These amounts explain why the payable bill may not become zero even when net energy consumption is zero.

How Can I Calculate My Actual Self-Consumption?

Your net meter usually shows import and export figures, while the inverter application or solar generation meter shows total solar production.

Use this formula:

Solar self-consumption = Total solar generation − Export units

Using the earlier example:

360 − 140 = 220 units self-consumed

You can then calculate total household consumption:

Total consumption = Grid import + Solar self-consumption

230 + 220 = 450 units

This calculation is useful for checking whether your solar system is properly sized for your consumption pattern.

How to Get More Value From Net Metering

Try to operate flexible loads during solar-generation hours. Washing machines, water pumps, dishwashers and daytime electric-vehicle charging can use solar electricity directly.

Direct consumption can be particularly important where export credits are restricted, settled at a lower rate or subject to annual adjustment.

Also compare monthly inverter generation with the import and export readings on your bill. A sudden reduction in generation may indicate shading, dust, inverter faults or a system outage.

Important India-Specific Note

Net-metering arrangements are implemented through state-level regulations and DISCOM procedures. Eligibility limits, sanctioned-load conditions, meter charges, banking periods and surplus-energy settlement can differ between states.

Before estimating savings, confirm:

• Whether your connection is approved for net metering.
• The maximum permitted rooftop-solar capacity.
• How excess export units are carried forward.
• The annual settlement date.
• The rate paid for unused surplus energy.
• Whether any additional grid or meter charges apply.

Grid-connected rooftop solar installations are also processed and verified through the relevant DISCOM mechanisms under government rooftop-solar programmes.

Frequently Asked Questions

·        Does the net meter record total solar generation?

• Usually, no. It records electricity imported from and exported to the grid. Total solar generation is generally available from the inverter monitoring system or a separate solar generation meter.

·        Are exported solar units the same as total generated units?

• No. Some solar electricity is consumed directly inside the home. Only the surplus reaches the grid and appears as exported energy.

·        Will a 3 kW solar system always make my bill zero?

• No. The result depends on monthly generation, electricity consumption, daytime usage, seasonal weather, tariff structure and local net-metering rules.

·        Does net metering provide backup during a power cut?

• No. A standard grid-tied solar inverter normally shuts down during a grid outage for safety. Backup requires a compatible hybrid inverter, battery system and approved electrical arrangement.

·        Is net metering better than a battery?

• They solve different problems. Net metering provides bill credits for surplus energy, while a battery stores energy for later use or backup. The better financial choice depends on export-credit rules, outage frequency and battery cost.

Conclusion

Net metering reduces your bill by allowing surplus rooftop-solar electricity exported during the day to offset electricity imported from the grid.

In the example above, a home consuming 450 units generated 360 solar units. After accounting for direct solar use and exported energy, only 90 units remained billable. At an illustrative rate of ₹7 per unit, the energy charge fell from ₹3,150 to ₹630.

The simplest way to understand your solar bill is to track three numbers every month: total solar generation, grid import and grid export.