Rooftop Solar Power System in India: Indian Guide

Solar PV market is growing well in India. And with this growing market consumers are getting more and more aware about technologies and products in solar rooftop systems. But, even with growing awareness consumers still lack proper knowledge about these products. So we thought of helping our readers by writing a solar PV panel guide for Indian consumers. In this guide we’re going to cover a wide variety of topics from types of solar panels to the efficiency and warranty details. Moreover, how these panels react to temperature variations and what certifications one needs to set these up.

Types of solar PV panels:

We won’t be going into the technical details of all these types. Briefly, solar PV panels are of three kinds: Mono crystalline, Multi/Poly-crystalline and lastly Thin Film(CdTe, CIGS, Amorphous crystalline etc). The most commonly available panels are poly-crystalline/multi-crystalline PV panels in India. This is because these are the most average PV panels, not very expensive and at the same time quite efficient too. For a detailed description of these different types you can visit this link.

Factors affecting performance of solar panels:

  1. Direction: India is a country in the northern hemisphere of the globe. Hence, PV panels without any sun tracking mechanism, should face south direction for better output.
  2. Tilt/Angle of Inclination: Inclination is also a major factor which affects panel performance. This should be according to the latitude of the location (your inspection engineer would know this better).
  3. Shading: Shading is a key factor in calculating panel efficiency. Even a small panel area left in shadow can effect the output of the entire rooftop system. So plan your solar rooftop structure accordingly, so that it can get as much sunlight as possible. Also, keep in mind to clean panels once in a while.

Temperature Co-efficient of solar panels:

Every solar panel will have a temperature coefficient. The temperature coefficient represents the rate at which the panel will under perform at each increase in degree Celsius (°C). Most average panels have a temperature coefficient of between -0.2% /°C to -0.5%/°C, when tested under standard laboratory conditions, where ambient temperature is set to 25°C. The closer the temperature coefficient is to zero, the better the panel will perform when the temperature rises.

Efficiency of solar panels:

By definition, efficiency of solar panel is the amount of electrical output it gives for the amount of solar radiation falling on it per meter square. Efficiency is a factor that matters when the installing space is really scarce. Because the highly efficient panel outputs the higher amount of energy. But, the cost for highly efficient panels is also high.

So if you have plenty of roof space there’s no point in going for the most efficient one, in these cases average one’s will do as fine. And just as an example, consider a solar panel with efficiency 14% and area 1.5 meter square. If the amount of solar radiation falling on this panel is 1000 W/sq. mt., then this panel is capable of producing

1000*14%*1.5 = 210 W.

Approvals/Certifications for solar PV panels:

Grid-connected solar panels sell power to DISCOMs, which in turn are monitored by Ministry of New and Renewable Energy. So, it’s obvious these rooftop solar plants needs certain certifications and approval from the government. Certification is good because it rules out bad quality products from market. MNRE mandates these certifications for different panel types:

  • For crystalline silicon terrestrial PV modules: IEC 61215/ IS 14286.
  • For thin film terrestrial PV modules: IEC 61646
  • Also, the panels must conform to IEC 61730 part I requirements for construction and part II requirements for testing, safety qualification
  • For highly corrosive atmosphere the panels must qualify Salt Mist Corrosion Testing as per IEC 61701/ IS 61701.

Warranty and Guarantee of solar panels:

Solar rooftop systems are a long term investment (usually 20-25 years), so it’s natural for consumers to expect longer warranty periods from these setups. Usually Indian manufacturers give warranty in the range 1-5 years and performance guarantee as follows:

  • 90% of the rated output for 1st ten years.
  • 80% of the rated output for next ten years.

This was a rough guide for Indian solar PV panels. Obviously, these factors varies from manufacturer to manufacturer ,so ask your provider for all these factors. Or, comment down below if you have any queries.

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