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Solar PV system comprises of electrical and electronic equipment such as solar modules, inverters, cables, switch gears etc. When all these components are combined together and placed in open space facing sunlight, the system starts generating electricity. The electricity thus generated can be stored in batteries or used directly by the consumer. If consumer is not storing electricity and not able to consume complete power generated by solar PV system, he can also feed the excess power to the utility grid. The function of each component of solar PV system is explained below along with images.


SPV Modules: It converts solar energy into electrical energy. There are primarily two kinds of PV modules:




Inverter: It converts the DC power produced by PV modules into AC power. The AC power is then either injected directly into the grid or consumed onsite


Balance of System (BoS): All components other than the PV modules are termed as balance of system. The components included in BoS are:

Mounting Structure: It is used to support and hold the PV panels. The structure is designed depending on the roof type, structural strength, cost, wind loads, etc.


Wiring and cabling: DC cables are used to connect solar panels and connect the string with inverter.


Safety equipment: Safety feature protects the solar system from being damaged or harming people during the events such as lightning event, power surge, and malfunctioning equipment. The safety equipment consists of safety disconnect, grounding equipment, and surge protection.


Bi-directional Meters: Bi-directional meters are used to keep track of the electricity that solar system produces and the electricity that is used from the grid.


There are two types of SPV systems that are most common:



Off-grid SPV systems are designed to operate independent of the electric utility grid and are generally designed and sized to supply certain DC and/or AC electrical loads. These types of systems use solar panels to generate electricity during morning time, and the electricity generated is stored in the battery to be used during the night time.


Grid-Connected SPV System

A grid-connected rooftop SPV system generates electricity that can either be injected directly into the distribution grid or used for captive consumption at the premises of the installation.


Frequently Asked Questions for Grid Connected Solar Rooftop Systems

  1. What is a Solar Rooftop System?

In a solar rooftop system, the solar panels are installed in the roof of any residential, commercial, institutional and industrial buildings. This can be of two types (i) Solar Rooftop System with storage facility using battery, and (ii) Grid Connected Solar Rooftop System. 

2.What is a Solar Rooftop System with Storage facility?

Such rooftop system has battery as storage facility. The solar electricity is stored in the battery and can be utilized during night also when the sun is not available.

 3.What is a Grid Connected Solar Rooftop System?

 In grid connected rooftop or small SPV system, the DC power generated from SPV panel is converted to AC power using power conditioning unit and is fed to the grid either of 33 kV/11 kV three phase lines or of 440/220 Volt three/single phase line depending on the capacity of the system installed at institution/commercial establishment or residential complex and the regulatory framework specified for respective States. 

 These systems generate power during the day time which is utilized fully by powering captive loads and feed excess power to the grid as long as grid is available. In case, where solar power is not sufficient due to cloud cover etc., the captive loads are served by drawing power from the grid.

4.Where such plants can be installed?

 Such rooftop systems can be installed at the roofs of residential and commercial complex, housing societies, community centers, government organizations, private institutions etc.

5.What is the average cost of grid connected rooftop solar systems?

The average cost of grid connected rooftop solar systems is about Rs. 60 per watt or Rs. 6.0crore per MWp capacity.

6.What are the other fiscal incentives are available for Solar Rooftop Systems?

There are provisions of concessional import duty/excise duty exemption, accelerated depreciation and tax holiday for setting up of grid connected rooftop power plants.

7.What efforts Government is making to providing loans for solar rooftop systems?Department of Financial services has instructed to all Public Sector Banks  to encourage home loan/ home improvement loan seekers to install rooftop solar PV plants and include cost of system in their home loan proposals. So far, nine PSBs namely Bank of India, Syndicate Bank, State Bank of India, Dena Bank , Central Bank of India, Punjab National Bank, Allahabad Bank, Indian Bank and Indian Overseas Bank have given instructions to extend loan for Grid Interactive Rooftop Solar PV Plants as home loan/ home improvement loan.

8.What is the size of grid connected rooftop solar system?

 The rooftop solar systems from 1 kWp upto 500 kWp or in combination can be set up on the roofs. 

9.How much roof area is required to set up the grid connected rooftop solar system?

About 10sq.m area is required to set up 1 kWp grid connected rooftop solar system.

 10.What are the advantages of Grid-Connected Rooftop Solar System?

  •  Electricity generation at the consumption center and hence Savings in transmission and distribution losses · Low gestation time · No requirement of additional land · Improvement of tail-end grid voltages and reduction in system congestion with higher self-consumption of solar electricity · Local employment generation

 11.Net metering

The grid connected rooftop system can work on net metering basis wherein the beneficiary pays to the utility on net meter reading basis only. Alternatively two meters can also be installed to major the export and import of power separately. The mechanism based on gross metering at mutually agreed tariff can also be adopted. 12.Feed-in-Tariff

 In feed-in-tariff the Government offers a tariff for purchase of the solar power generated from such plants. 

13.Among net metering and feed-in-tariff what is preferred?

Net metering mechanism is more popular among States. 

14.In case of grid failure, is there any chance for shocks to the person who is repairing?

In case the grid fails, the solar power has to be fully utilized or stopped immediately feeding to the grid so as to safe-guard any grid person/technician from getting shock (electrocuted) while working on the grid for maintenance etc. This feature is termed as ‘Islanding Protection’.

15.What are the grid connectivity levels for such systems?

The Projects under these guidelines fall within two broad categories i.e.(a) the projects connected to HT voltage at distribution network (i.e. below 33 kV) (b) the projects connected to LT voltage i.e. 400/415/440 volts (3-phase) as the case may be or 230 volts (1-phase). Accordingly, the projects may be under the following two categories.


Category 1: Projects connected at HT level (below33kV) of distribution network

The Projects with proposed installed capacity of minimum 50 kW and upto 500 kW and connected at below 33kV shall fall with in this category. The projects will have to follow appropriate technical connectivity standards in this regard.

Category 2: Projects connected at LT level (400 Volts-3 phase or 230 Volts-1 phase)

The Projects with proposed installed capacity of less than100kW and connected of the grid at LT level (400/ 415/ 440 volts for 3-phase or 230V for1-phase) shall fall within this category.

What is the gross potential of solar power in the country?

India is endowed with vast solar energy potential. About 5,000 trillion kWh per year energy is incident over India’s land area with most parts receiving 3-5 kWh per sq. m per day.  Based upon the availability of land and solar radiation, the potential of solar power in the country has been ass

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