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Updated 2020: Top FAQ on Rooftop Solar Systems

Updated: Jun 18

Solar Power is a very precise industry; which means there are a whole lot of very specific questions about our products and services. So we have compiled a list of questions that we get asked the most by our customers.



1. WHAT IS A ROOFTOP SOLAR SYSTEM?


Rooftop solar systems use solar panels in combination with a solar inverter to generate electricity for self consumption. As the name suggests, these systems can be installed on the roof of any residential, commercial or industrial buildings.


There are two types of solar systems:

  1. On-Grid Solar System: Such systems are connected directly to the grid and do not require any batteries to operate as they get their reference voltage directly from the grid. They are ideal for buildings which have a high energy consumption and have a 24 hour supply of electricity.

  2. Off-Grid Solar System: Such systems are independent from the grid and operate with the help of batteries. They are ideal for buildings which have a low energy consumption and experience long durations of power cuts.



2. HOW DOES A ON-GRID SOLAR SYSTEM WORK?


Any electricity generated by On-Grid Solar Systems during day time is first consumed by powering captive loads. Any surplus energy left is exported to the grid. At night, when there is no solar energy available, all captive loads are powered from the grid.


At the end of the month, any left over units are carried forward to the next month. At the end of the financial year, all accumulated units are purchased by the utility company at the APPC i.e. Average Purchase Pool Price which is about Rs. 3/- Unit. and the amount credited to your billing account.



3. WHAT IS THE CAPACITY OF THE ROOFTOP SOLAR SYSTEM THAT I CAN INSTALL?


As per Maharashtra Electricity Regulatory Commission (Net Metering for Roof-top Solar Photo Voltaic System) Regulations 2015, you can install a solar power plant up to 100% of your contract demand or sanctioned load. Different states may have different policies. Please check with your installer for more information.


If the capacity of your solar power plant is more than your sanctioned load, you will have to apply for a load extension.


Click here to download a copy of the MERC (Grid Interactive Roof-top Renewable Energy Generating Systems) Regulations 2019.



4. HOW MUCH AREA DO I NEED TO INSTALL A ROOFTOP SOLAR SYSTEM?


A 1 Kilowatt (KW) Solar Power Plant requires about 10 Sq.Mt. i.e. 110 Sq.Ft. of area for a shadow free installation. The orientation of the solar panels should be preferably south facing.



5. HOW MANY UNITS OF ELECTRICITY CAN A SOLAR SYSTEM GENERATE?


A 1 Kilowatt (KW) solar system can generate an average of 4.15 units of electricity a day under Standard Test Conditions (STC). However, in real time conditions you can expect more generation if the solar power plant is designed and maintained properly.



6. WHAT IS THE SERVICE LIFE FOR THE ROOFTOP SOLAR SYSTEM?


Service life of a solar system is 25 years. Upon successful commissioning of the system, a Net Metering Agreement is entered into with the DISCOM for a period of 20 years after which the solar system needs to be disconnected from the grid. 



7. WHAT IS THE WARRANTY ON SOLAR PANELS?


Solar Panels come with two different types of warranties. It is very important to understand the difference between the two. One is called a Manufacturer's Warranty (also known as Product Warranty) and the other is called as Performance Warranty (also known as Power Warranty).

  • Solar Panels come with a Industry Standard 10 Year Manufacturer's Warranty

  • Solar Panels come with a Industry Standard 25 Year Performance Warranty

Some brands offer longer product warranties. Speak to your installer about your options.



8. HOW MUCH WILL IT COST ME TO INSTALL A ROOFTOP SOLAR SYSTEM?


The benchmark cost for the year 2019-2020 as set forth by the Ministry of New and Renewable Energy (MNRE) is as follows:

  • Above 1 KW and up to 10 KW @ Rs. 54/ Watt 

  • Above 10 and up to 100 KW @ Rs. 48/ Watt

  • Above 100 KW and up to 500 KW @ Rs. 45/ Kilowatt

Actual cost may vary depending on product quality and site conditions. To learn about the benchmark cost for special category states and more, download the Benchmark Cost for the Year 2019-2020



9. IS THERE ANY SUBSIDY AVAILABLE FROM THE GOVERNMENT?


Yes. Government subsidy is available for the year 2019-2020 for residential customers only. For 1 to 3 KW capacity, subsidy available is 40% of the benchmark cost. For 4 to 10 KW capacity, subsidy available is 20% of the benchmark cost. No subsidy for capacity beyond 10 KW. Benchmark cost for subsidy calculation is Rs. 50/ Watt.



10. WHAT IS NET METERING?


Net Metering is a utility billing mechanism available in most states that offers credit to customers who are making excess electricity with their solar systems and sending it back to the grid.


Upon successful commissioning of your solar system, your current electricity meter will be replaced by a Net Meter. A Net Meter is a bi-directional meter which can keep track of electricity that is exported and imported from the the grid.


Click here to download a sample of the Net Metering Agreement.

Kindly note that every DISCOM will have a different format for their Net Metering Agreement. Check with your DISCOM for more information.



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