Planning to go Solar? 4 things you should know

Solar Rooftop

In series of blogs, I am going to give you tips and tricks to make your solar journey enjoyable. When you are considering to go solar, below 4 things are must know.

1. Is my roof suitable for going solar?

First you need to check the age and condition of the roof. As solar panels have long life of 25+ yrs, it’s advisable to install on a strong roof. If the roof is very old, it is better to repair/replace the roof before installation. Solar rooftop system can be installed on all kinds of roofs like flat concrete roof, sheet roof, tiled roof etc. Customized panel mounting structure can be used to install solar panels on all kinds of roofs, even if roof is not strong enough to take panel loads.

2. Should I go for On Grid/ Off Grid system?

If you are planning to go solar in order to reduce electricity bills, then On-Grid system is the right choice. This system comes with no batteries and it uses grid as a virtual battery to store excess power generated. Now-a-days DISCOMs are promoting solar power implementation with net-meter facility to make solar rooftop systems affordable.

On the other hand, if you are planning to go solar in order to have an uninterrupted power supply, then off-grid or Hybrid Solar rooftop system is the ideal choice. Solar can act as an UPS for you. Here, Solar rooftop powers electrical loads during daytime, and stores the excess energy in batteries. And through these batteries you can get power supply during power cuts and night time.

3. What capacity solar rooftop should I choose?

Well, the capacity is mainly determined by your electricity requirements. Your monthly electricity bill will be best indicator about the solar rooftop system capacity requirement. Available Roof area is also an important deciding factor. To install 1kW solar system, around 70 to 100sqft of shadow free roof area is required. Sanctioned load (your electricity bill will have this data) is another limiting factor for grid connected solar roof top systems. DISCOMs (govt or private electricity Distribution Companies) usually have set rules for what capacity solar you can install on your roof(usually it is 75% to 100% of sanctioned load for different users).

Solar Calculator is a good first cut tool, to help you decide on solar rooftop capacity for you.

The number of Solar Panels that you need depends on the rating of Solar Panels. For instance if you decide to install 1kW (ie 1000W) solar system with 335Wp panel rating, then you need to install 3 (=1000W/335W) panels, with 250Wp rating, you need 4 panels.

Commonly used solar panel sizes are around 2m length X 1m width X 40 mm thick. Panels with rating below 200Wp, may come with smaller sizes.

4. How do I choose the right installer?

Look for the Expertise. A good installer will always help you take an informed decision.

Installer should show you how the solar rooftop generation helps in recovering your investment over years. Based on your location, installer should use local solar irradiance data (published by MNRE, NASA, NREL, ISRO etc) and shadow analysis of your roof to arrive at solar generation units you can achieve. That gives the best estimate to take decision.

As an owner, you should be aware of the choices available in the technologies, panels, inverters, monitoring systems, panel mounting structure options etc to help in taking informed decision. Look for the products they offer in terms of approvals, standards and warranty durations.

It is wise to choose an installer, who gives components with longer warranty period. As the life of the solar system is more than 25 years, this will reduce your maintenance and replacement costs significantly.

Safety of the system becomes critical as it is installed on your roof. Always check, whether they follow safety standards during installation. For solar rooftop system installation IS and IEC standards needs to be followed and all the components should be IP65 compliant.

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About the author

Renewable and Sustainable living enthusiast is Alumnus of IIT Madras, with 12 years of experience in Engineering, Business Development and Entrepreneurship across Government establishments, MNCs and Start-ups. Mentored in entrepreneurship by ISB Hyderabad

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