Solar Panels

With the temperatures soaring in the country, it’s the time of the year when no one wants to step out of the comfort of their homes. Just a walk to the nearest shop itself could drain you of all your energy.

But thinking about it, the heat in itself is a form of energy that can be tapped into, and it is a form of energy that is available abundantly.

India being a sub-tropical country,  most of the country has about 300 clear, sunny day, meaning that India is blessed with an abundance of solar energy. It is calculated that India receives about 5,000 trillion kilowatt hours (kWh) of energy in the form of solar radiation, every year. Tapping into this energy could be a solution to the growing green-energy crisis.

Using solar energy to power the entire house itself is something that is relatively new to this country.

If you are one of those looking to tap into this plenteous energy, we have got some vital information for you which will help you in exploiting this inexhaustible energy to the fullest. The first and foremost thing that you will need is solar panels. ( Refer Solar Inverter , Solar Light )

The type of the solar panel used will majorly determine the amount of energy produced and more importantly, the efficiency of your entire system.

Types of Solar Panels

There are a variety of solar panels available in the market each with different power ratings, efficiencies and other related information (which could seem like Greek and Latin), which could make buying or choosing the kind of solar panel seem like a formidable task.

Before getting into that, it is worth knowing the

various types of solar panels available,

how they work and

what are there pros and cons,

to help make a better decision before investing in the solar panels you want.

Don’t worry; we won’t get into a lot of the technicalities and will explain them without much of jargon.

There are basically three types of solar cells or solar panels –

Mono-crystalline silicon solar panels,

Poly-crystalline silicon solar panels and

Thin-film solar panels.

Mono-crystalline Silicon Solar Panels

 

Monocrystalline Solar Panels

 

Mono-crystalline Silicon solar panels, as the name suggests, is made out of a single piece of silicon ingot. Silicon ingots are high purity silicon melted and crystallized into the shape of a cylinder.

The higher grade of silicon used in this type of solar panels makes them the most efficient of the three types of solar panels that are available. They have an efficiency ranging between 15%-20%.

They have the longest life among the three types of solar panels, and most manufacturers put a 25 year warranty on mono-crystalline silicon solar panels.

Their higher efficiency means that they are able to produce more power while taking up less space, as compared to the other two.

But all these benefits come at a price, quite literally. Mono-crystalline solar panels though the most efficient, are also the costliest of the lot. In some cases, the extra buck may not be worth the added power generated by them.

Moreover, the entire circuit can break down if it is covered by shade, dirt or snow. This calls for added equipment like micro-inverters, which results in more added costs. This may not necessarily be what you need at home or with a limited budget. But they are more aesthetically pleasing which can add color to your house.

Poly-crystalline Silicon Solar Panels

 

Poly-crystalline Solar Panel

 

Unlike mono-crystalline Silicon solar panels, poly-crystalline solar panels are made of wafers of silicon put together.

Silicon is melt and poured into square molds. Wafers are then cut out from the square silicon molds and put together.

This type of solar panels uses silicon of lower grade, and the level of purity of the silicon is lower in them, which gives them a bluish color with a tinge of white in them.

Solar panels of this type have efficiencies ranging between 13%-16%. But on the brighter side, they are considerably cheaper than the mono-crystalline silicon solar panels.

Considering that their efficiency is just a bit lower than the mono-crystalline ones and that they are cheaper as well, it might better to invest in poly-crystalline silicon solar panels in some cases.

Thin-Film Solar Cells

 

Thin Film Solar Panels

 

Thin-film solar cells are second generation solar panels, which are made by depositing either one layer or several layers of photovoltaic material on a substrate.

Photovoltaic materials are the materials that are capable of producing electricity when exposed to sunlight. Various photovoltaic materials are used in thin-film solar panels and each of them has a different working technology. Depending on the technology, thin-film solar modules have efficiencies between 7%-13%.

They are the only type of solar panels that can be made flexible. They are more resistant to high temperatures and the effect of shading is very little on its performance.

They have a pleasing look and will give your house a dramatic facelift, but thin-film solar panels are not very effective in residential applications. They also degrade faster and hence have a shorter life compared to mono- and poly-crystalline silicon solar panels.

Buyer’s Guide

Just knowing about the types of solar panels might still not help you take the best decision. So, we have put together a list of criteria that you should consider while purchasing solar cells.

Solar Panel Ratings

Each solar panel has a power rating which shows the measure of energy it can create under particular modern standard test conditions.

Though a solar panel would practically experience such conditions for a very small period of time, power ratings are a useful parameter to compare solar cells.

A solar panel with a higher power rating would mean that it can produce more power under similar conditions than a solar panel with a lower power rating.

But this does not really give you the entire picture. Solar panels with greater power ratings do not necessarily imply greater efficiency or a superior technology.

If two solar panels are having the same efficiency ratings, but if one of them has a greater power rating than the other, then it is very much likely that the one with the greater power rating is bigger in size compared to the other one. Therefore, it is essential to consider other parameters as well.

Power Tolerance

Power tolerance is the range of power that a solar panel will produce above or below its power rating at any given time.

Power tolerance tells you the range of power that a solar cell will produce under real-time conditions.

If a solar panel has a power rating of 220W with a power tolerance of ±10%, this means that the panel will produce anywhere between 198W and 242W at any given time.

A solar panel with a small range of power tolerance is recommended as it represents more certainty in the power produced by the solar cell. There are solar cells these days that come with a 0% negative power tolerance. Such panels, for example, having a power tolerance of -0%,+10% and a power rating of 220W would produce anywhere between 220W and 242W at any given time.

Such panels are definitely more beneficial, as they are able to produce more power at all times. They are also known as positive power tolerance panels.

Solar Cell Efficiency

Solar cell efficiency is a measure of how effectively the solar panel converts solar radiation into electricity. Most solar panels, these days, have an efficiency of just above 20%.

A higher solar panel efficiency rating implies that the solar panel can produce more electricity for a given amount of solar radiation on the solar panel.

This is probably the most important factor that you have to consider while purchasing or choosing solar panels.

For two solar panels of the same size, the one with the higher efficiency will produce more electricity.

The only way to get more electricity from a solar panel having the highest efficiency possible is by increasing its size. And that’s what makes this the most important factor to consider as the right set of solar panels will enable you to produce the maximum amount of energy while taking up as less space as possible.

Temperature Coefficient

Though the solar panel is supposed to be able to produce more energy when exposed to more sunlight. But on the contrary, the more sunshine that you get, the hotter the solar cells will get and that, in turn, will reduce the amount of energy produced.

Solar panels are all rated at 25 degrees Celsius, above which the amount of electricity produced by them tends to go down.

The temperature coefficient is a parameter which will give you the amount of decrease in power produced for each degree Celsius rise in the temperature of the solar cell.

For example, if a solar cell rated at 250W has a temperature coefficient of -0.5% per degree Celsius and the temperature of the solar cell is 50 degree Celsius. Then, the power loss is a little more than 31W which means that the solar cell will be able to produce slightly less than 220W of power at 50 degree Celsius.

The method to find out the power loss involves a little bit of calculation and can be done as follows.

Temperature increase of solar cell= 50 degree Celsius – 25 degree celcius= 25 degree Celsius

Total percentage drop in power produced= 0.5 x 25=12.5%

Power loss= 12.5% x 250=31.25 W

Therefore, the panel power is 250-31.25=218.75W

Manufacturer Assurances

Manufacturer assurances are the warranties that a manufacturer gives while purchasing solar panels. This would have been quite straightforward for other products but when it comes to solar panels, it is a bit tricky.

The power produced by any solar cell decreases year after year, the biggest decrease coming after the first year. This decrease in power production is called as panel degradation.

Most manufacturers provide a power production warranty guaranteeing that their panels will retain a certain percentage of their power producing capacity within the next 25 years, usually it is 80%. The key looks for solar cells which will retain a higher percentage of its power producing capacity.

The decrease in power output in a solar cell over a year is called as the degradation rate. Some manufacturers also provide a guarantee for the degradation rate, usually about 0.7% drop in power production over a year. Here, a smaller percentage is better.

A third warranty is provided for solar panels which cover the materials. The materials warranty acts as a guarantee against failure due to manufacturing defects, environmental issues, and durability. Most manufacturers provide a warranty of 10-12 years for their solar panels.

Top 5 Solar Panels Available in India

1. Waaree’s WS-250 Solar Panel (Editor’s Choice)

 

Waaree WS 250 Solar Panel

 

Waaree’s WS-250 solar panel is a solar panel from their Aditya series of solar panels, which come with a power rating between 240-270 W.

The WS-250 is a 60 cell, poly-crystalline solar panel which is capable of producing up to 250 W of power, with a positive power tolerance of +5%.

They have a module efficiency of 15.4% and a temperature coefficient for the power of -0.38% per degree Celsius.

They come with a 5-year product warranty and a 10 years performance warranty of 90%, and a 20 years performance warranty of 80%.

They are sand and dust storm resistant, as well as salt mist, ammonia, and hail resistant.

Features:

  • 60 cell poly-crystalline silicon solar panel.
  • Has a power rating of 250 W.
  • Has a 5 years materials warranty and a 10 years 90% performance warranty.

Pros:

  • The efficiency of 15.4% is the best in the market in its range.
  • The temperature coefficient of -0.38% for the power produced.
  • Sand and dust storm, salt mist, ammonia and hail resistant.
  • Capable of withstanding up to 2400 Pa wind loads and 7500 Pa snow loads.
  • Positive power tolerance of 0-5%.

Cons:

  • Not really a drawback, but other solar modules tend to come with a 25 years performance warranty, while this comes with 20 years 80% performance warranty.

 

 

2. Tata Power’s TP300

 

Tata TP310 Solar panel

 

The TP300 is a solar panel from the TP300 series by Tata Power, which is one of its elite set of solar panels.

It is a multi-crystalline silicon panel and has a wattage rating of 300 W, with a positive power tolerance of 0-5%.

It has a solar cell efficiency of 15.1% and comes with a 25-year linear power output warranty. The linear power output warranty along with the positive power tolerance gives this a huge edge over the solar panels that are available in the market.

It has a temperature coefficient of -0.40% per degree Celsius, which is one of the best temperature coefficients in the market.

It also has a very robust design and is claimed to be capable of withstanding loads of up to 5400 Pa from snow or the wind which is equal to a load of 916 kg.

Features:

  • Multi-crystalline silicon solar panel with a power rating of 300 W.
  • Has a solar efficiency of 15.1%.
  • Has a linear power output warranty of 25 years.
  • Is capable of withstanding up to 5400 Pa of snow load and wind loads.

Pros:

  • Has a positive tolerance of 0-5% which means that you are bound to produce 310 W for sure.
  • The temperature coefficient of -0.40% for power produced.

Cons:

  • The efficiency of 15.1% is not the best in the market.

 

 

3. Goldi Green’s 300 PM Solar Panel

 

Goldi Green 300PM Solar Panel

The 300 PM (PM for a polycrystalline module) solar panel is a solar panel of Goldi Green’s 72 series polycrystalline module series.

Goldi Green’s solar panels are known for their high efficiencies and the 300 PM doesn’t disappoint, coming with an efficiency of 15.5% which is pretty good for a polycrystalline module. The 300 PM is a 300 W poly-crystalline solar module and has a positive power tolerance of +3%.

It has a temperature coefficient of -0.42% per degree Celsius for the power produced by the solar panel and comes with a 10-year performance warranty of 90% and a 25-year performance warranty of 85%.

The module itself has a good mechanical strength and is capable of withstanding snow loads up to 5400 Pa, and comes with a 10 years product warranty from Goldi Green.

Features:

  • 72 cell polycrystalline silicon solar panel.
  • Has a power rating of 300 W.
  • Comes with a performance warranty of 90% for 10 years.
  • Capable of withstanding snow loads up to 5400 Pa.
  • 10-year material warranty.

Pros:

  • The efficiency of 15.5% is one of the best in the market.
  • Has a positive tolerance of 0-3%.

Cons:

  • Has a temperature coefficient of -0.42% for the power produced, which could be better.

 

 

4. Su-Kam 100 W Solar Panel

Su-Kam 100W Solar Panel

Su-Kam is one of the leading players in solar energy in India and has received several prestigious awards including India’s most trusted brand in its category in 2015.

This 100 Wp solar panel from Su-Kam is a poly-crystalline silicon solar panel with an efficiency of almost 15%, 14.9% to be precise. It has a power tolerance between -3% to +3%, with a module voltage of 12 V.

It comes with a 25-year linear output with a degradation rate of less that 0.75% each year. The 5-year product warranty is the one category where you are left wanting for more when it comes to this solar panel.

Coming to its mechanical strength, it has a hollow chamber profile frame which ensures high rigidity and is capable of withstanding snow loads of up to 890 kg and the wind speeds up to 190 kmph.

Features:

  • Poly-crystalline silicon solar panel with a power rating of 100 W.
  • Has a 25-year linear output warranty with a 5-year product or material warranty.
  • Has an efficiency of 14.9%.

Pros:

  • 25-year linear output warranty.
  • Has good mechanical strength.

Cons:

  • Power tolerance of ± 3% in a time where solar panels come with positive power tolerance, is definitely a big disadvantage.

 

 

5. EMMVEE 60 W Solar Panel

 

Emmvee 60W Solar Panel

EMMVEE specializes in developing solar modules and systems, both for On-grid and off-grid or standalone purposes.

This 60 Wp solar panel is 36 cell, polycrystalline silicon panel with a module efficiency of 13.6%. It is capable of achieving up to 96% of its efficiency even at low irradiance.

The temperature coefficient for the rated power is -0.43% per degree Celsius. It is capable withstanding snow loads of up to 5400 Pa, and even hail traveling at 83 kmph.

It comes with a 5-year product warranty and a 90% performance warranty up to 10 years and an 80% performance warranty up to 25 years.

Features:

  • 36 cell polycrystalline silicon solar panel.
  • The power rating of 60 W.
  • Comes with a 10 year 90% performance warranty and a 5-year materials warranty.

Pros:

  • Very good mechanical strength.
  • Decent efficiency for its range.

Cons:

  • Temperature coefficient for the power of -0.43% is quite a lot of power lost for every degree Celsius rise in the temperature of the solar panel.

 

 

Conclusion

As you might be aware by now, when it comes to purchasing solar panels, it depends on various factors and the same may not work for everyone.

Choosing the right set of solar panels is tricky, as the same set of solar modules may work wonders for one, but the same ones may not give the best results for another.

It’s all about finding out what suits your purpose and application the best. Having said that, we are pretty sure this article would have set you off in the right direction to acquiring the right set of solar panels and in making the best decision.

Plus, if I had to suggest a particular solar panel, I would definitely go with Waaree’s WS-250 Solar Panel for obvious reasons, as are stated above.

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