New & Renewable Energy Development Corporation of Andhra Pradesh Ltd.,
(A State Govt. Company)

Net metering and Gross metering

Net Metering

What is Net Metering?

Under net metering, electricity generated by the Solar Rooftop System is first utilized by the consumer to meet their internal/captive requirements. Excess electricity, if any, is exported to the grid. Subsequently, when the consumer imports power from the grid, the exports are adjusted against the imports, lowering the electricity bill.

Net Metering

What is a Net Meter?

A net meter (bi-directional meter) records the energy imported from the grid to meet the load and surplus energy exported to the grid after self-consumption. Both energy import and export are recorded in the net meter. The difference between export and import readings is the actual energy consumed/delivered.

What is the Method of Billing Under Net Metering?

The energy generated from Solar Rooftop System shall be adjusted against the consumption of energy from the DISCOM by an eligible developer/consumer every month. In case of groups/societies, the energy generated shall be prorated as per the installed capacity share indicated in the Agreement between the group/society and DISCOM. This computed energy share shall be adjusted against the consumption of energy for each consumer every month.

In case of excess generation (after energy adjustment) injected into DISCOM network in a billing month will be carried forward to the next month till every quarter end and settlement will take place on an Average Cost of Supply (ACOS) basis for net metering as determined by APERC from time to time.

Example of Billing under Net Metering for Individual Consumers

Domestic consumer installs a 2 kWp Solar Rooftop System which generates an average of 288 units per month. We have considered the following Retail Tariff and ACOS of INR 5.54/kWh to illustrate the benefits under net metering for individual consumers.

Retail Tariff for FY 2017-18

Consumer Category Unit Fixed Charge (INR/Month) Energy Charge (INR/kWh)
LT Category-I: Domestic (Telescopic)
Group A: Annual Consumption ≤ 900 Units During FY 2016-17      
0-50 kWh   1.45
51-100 kWh   2.60
101-200 kWh   3.60
Above 200 kWh   6.90

Illustration on Net Metering for Individual Consumers

Month Month Billed Demand/ Consumption From Grid (kWh)
A
Solar Rooftop System Generation (kWh)
B
Net Energy Generated/(Net Energy Consumed) (kWh)
B - A = C
Net Payment by DISCOM* (INR)
C X ACOS = D
Jan 250 288 38 210.52
Feb 350 288 (62) 0
Mar 400 288 (112) 0

*Amount payable for the net energy generated is credited to the consumer on a monthly basis and payment settlement is done on a quarterly basis.

Example of Billing Under Net Metering for Group Consumers

Group Consumers install Solar Rooftop System, which generates an average of 1,000 units per month. We have considered the ACOS of INR 5.54/kWh for illustrating the benefits under net metering for group consumers.

Illustration on Net Metering for Group Consumers

Name of the Consumer Investment in Solar Rooftop System (Percent) Units to be Allotted (kWh) Monthly Consumption (kWh) Net Payment
Consumer A 50 500 400 Amount to be credited for 100 kWh
Consumer B 30 300 350 Bill to be issued for 50 kWh
Consumer C 20 200 200  

Gross Metering

What is Gross Metering?

Under gross metering, all the electricity generated by the Solar Rooftop System is exported to the grid and all the electricity required for consumption by the consumer is imported from the grid. The consumers are paid a feed-in tariff (FIT) for the electricity exported to the grid.

Gross Metering

What is the Method of Billing Under Gross Metering?

In case of gross metering, the generator shall pay for the energy utilized in a billing month as per applicable retail supply tariff decided by APERC to the concerned DISCOM. Energy supplied to DISCOM by the developer/consumer will be paid monthly, based on ACOS as determined by APERC from time to time (net amount will be credited). A limit of 20 percent Capacity Utilization Factor (CUF) for the installed SPV capacity is defined for all eligible developers in terms of energy, beyond which no payment shall be made by APDISCOM.

Example of Billing Under Gross Metering for Individual Consumers

Domestic consumer installs a 2 kWp Solar Rooftop System under gross metering framework which generates an average of 288 units per month. We have considered the following retail tariff and ACOS of INR 5.54/kWh for illustrating the benefits under gross metering for individual consumers.

Retail Tariff of FY 2017-18

Consumer Category Unit Fixed Charge (INR/Month) Energy Charge (INR/kWh)
LT Category-I: Domestic (Telescopic)
Group A: Annual Consumption ≤ 900 Units During FY 2016-17      
0-50 kWh   1.45
51-100 kWh   2.60
101-200 kWh   3.60
Above 200 kWh   6.90

Illustration of Gross-Metering for Individual Consumers

Month Billed Demand /Consumption from Grid (kWh)
A
Billed Demand /Consumption from Grid (INR)
(A* Applicable Tariff as per APERC) = B
SRP Generation (kWh)
C
SRP Payment (INR)
(C* ACOS) = D
Net Monthly Payment by DISCOM (INR)
(D - B)
Jan 250 907.5 288 1,595.52 688.02
Feb 350 1,597.5 288 1,595.52 0
Mar 404 1,970.1 288 1,595.52 0

Example of Billing Under Gross Metering for Group Consumers

Group consumers install SRTPV, which generates an average of 1,000 units per month. We have considered ACOS of INR 5.54/kWh for illustrating the benefits under gross metering for group consumers.

Illustration of Gross-Metering for Group Consumers

Name of the Consumer Investment in SRP Plant(Percent) Units to be Allotted (kWh) Monthly Consumption by Consumer (kWh) Generation Amount (INR) Bill Amount Net Payment (INR)
Consumer A 50 500 400 2,770 1,942.5 827.5 to be credited
Consumer B 30 300 400 1,662 1,942.5 208.5 bill to be issued
Consumer C 20 200 200 1,108 562.5 545.5 to be credited

To ensure that the SRTPV system is not misused, DISCOM has set an energy limit of 20 percent CUF of the installed capacity. Any surplus injection into grid beyond this limit is considered as inadvertent and no payment shall be made for it.