Frequently asked questions

1. What is a Solar Roof-top System?

In a solar rooftop system, the solar panels are installed on 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 too, 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 can such plants be installed?

Such rooftop systems can be installed on the roofs of residential and commercial complexes, 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. 80 per watt or Rs. 8.0 crores per MWp capacity.

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.

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

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 10.00 Sq.Mt. 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.

6. What is 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 measure the export and import of power separately. The mechanism based on gross metering at mutually agreed tariff can also be adopted.