Team SBSolar panels are defined as panels designed to absorb the sun's rays as a source of energy for generating electricity. A photovoltaic effect is achieved when light is converted into electricity caused by absorbing photons and discharging electrons. These photons are pockets of electromagnetic energy and materials that cause a photovoltaic effect are called PV or solar cells.
Solar cells are made of semiconductor materials, for example, silicon. Silicon, being conductive, is used to make thin semiconductor wafers to form an electric field that is positive and negative on either side, respectively. There are two kinds of solar panels: monocrystalline and polycrystalline. If you are going to use solar power, it is vital to understand the difference between monocrystalline vs. polycrystalline solar panels.
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What are monocrystalline and polycrystalline solar panels?
The monocrystalline solar panel is made of monocrystalline silicon cells. The silicon that is used in this case is single-crystal silicon, where each cell is shaped from one piece of silicon. Polycrystalline solar panels, on the other hand, are made from multiple silicon pieces. In this case, small pieces of silicon are melted together to create the solar cell.
How are monocrystalline solar panels manufactured?
Creating silicon ingots
The first step towards making monocrystalline solar panels involves the extraction of pure silicon from silica sand quartzite (SiO2) to make the metallurgical silicon. Special ovens are used for this purpose and SiO2 and carbon are melted at over 2,552 degrees Fahrenheit producing 98% to 99% pure silicon. Once the purification process is complete, and the silicon is 99.999% pure, it is converted to a single silicon ingot. The silicon ingot depends on the temperature gradients, cooling rates, and rotation speeds.
Making silicon wafers
Using a wire saw, this single silicon ingot gets sliced into thin wafers of 1 mm or 0.0393 inches. These wafers are further washed clean and polished to remove all dust particles and scratches.
Making the wafers efficient
The surface of the wafer is flat and light rays may get reflected away. Therefore, the surface is roughened and etched to ensure that light gets refracted many times increasing the levels of efficiency.
Diffusion
Silicon wafers are p-type (positively charged) material. They need a positive-negative junction to conduct electricity. A layer of negatively charged phosphorus gets added to the wafer and the wafer is moved to an oven at 1,652 degrees Fahrenheit and gets injected with nitrogen. Mixing nitrogen with phosphorus creates a negative-type layer in the p-n junction.
Improving conductivity
A conductive silver alloy is pressed to the front of the silicon wafer to decrease any loss of electricity to ensure a perfectly transported power for conductivity.
Assembly
The final step of the manufacturing process involves assembling the wafers into rows and columns.
How are polycrystalline solar panels manufactured?
Best polycrystalline solar panels also need a highly pure grade of silicon, but they use silicon fragments instead of one ingot. After the purifying process, the silicon is left to fragment upon cooling. The fragments are melted and poured into cubic-shaped crucibles and cut into wafers. The rest of the process is similar to that of the best monocrystalline solar panel.
Monocrystalline vs. Polycrystalline solar panels: In-depth comparison
Both monocrystalline solar panels and polycrystalline solar panels are used to convert the sun's energy into electricity. However, there are differences between the two kinds of solar panels in their cell composition.
Solar cells used on monocrystalline panels are made of silicon wafers where the silicon bar is made of single-cell silicon and they are sliced into thin wafers. The electrons have more space to move around thereby allowing a greater flow of energy.
Solar cells used on polycrystalline solar panels are made of multiple pieces of silicon that are melted to form thin wafers. They are also known as multi-crystalline panels. In polycrystalline solar cells, the electrons have less room to move around because of the many crystals.
What do they look like?
Monocrystalline vs. polycrystalline solar panels appear differently. For instance, monocrystalline solar panels are dark black in color and have uniform darkness throughout. The thin wafers of silicon will have round edges because of their cylindrical shape creating gaps between the cells.
The polycrystalline solar panels will appear bluer in color because of the way sunlight falls and interacts with multiple crystals. The silicon wafers will not appear round-edged because they are cut from the cubic-shaped crucibles.
What materials are they made of?
Monocrystalline solar cells are made of silica sand, quartzite. Pure silicon is extracted from quartzite to make metallurgical silicon. The silicon is then purified and made into a single ingot. The single ingot is a homogeneous and cylindrical crystal.
Polycrystalline solar cells are also made from silica sand, quartzite. However, many silicon fragments are used. The molten silicon fragments when cooled and are melted into cubic-shaped crucibles.
How much are monocrystalline and polycrystalline panels?
One of the disadvantages of monocrystalline solar panels is that they are more expensive than polycrystalline panels. That is largely because of the manufacturing process. Manufacturing polycrystalline solar panels consume less energy and produce less waste than monocrystalline panels. This makes the monocrystalline solar panels costlier.
Manufacturing monocrystalline solar panels is energy-intensive and they produce a lot more silicon waste than polycrystalline solar panels. If you are on a tight budget, make sure you do a careful cost-benefit analysis to differentiate between monocrystalline vs. polycrystalline solar panels.
Monocrystalline vs. Polycrystalline solar panels: Efficiency
Monocrystalline solar cells are made from superior grade silicon with a single-crystal structure due to which, the electricity flows with little to no resistance having more space to move around. However, in the case of polycrystalline solar cells, the fragments that go into making the cells cause lower efficiency rates from 14 to 16%. This is one of the disadvantages of polycrystalline solar panels.
What about their temperature coefficients?
Studying the temperature coefficients of solar panels is to understand how well they function. Monocrystalline solar cells have a temperature coefficient of anywhere between -0.3%/°C and -0.5%/°C. If the temperature increases by one degree (Celsius), the monocrystalline cells are likely to lose 0.3% to 0.5% efficiency levels.
On the other hand, polycrystalline solar cells have a high temperature coefficient and will lose more of their efficiency levels when the temperatures rise, especially in hot locations.
How long can monocrystalline and polycrystalline panels last?
The lifespan of a solar panel depends on the degradation rate and the loss of energy production annually. Each year will see a decrease in power output by around 0.3% to 1%. Therefore, solar panels have a degradation rate of 0.3% to 1%.
Monocrystalline solar panels incur an efficiency loss of 0.3% to 0.8% and their degradation rate is around 0.5%. After the first ten years, the panels will operate at 95% efficiency and in twenty years, at 90% efficiency. Generally, monocrystalline solar systems come with a warranty of 25 years or more.
Polycrystalline solar panels lose their efficiency levels faster than monocrystalline panels. But, they can still have a lifespan of around twenty-five years.
What are the big-name brands in these fields?
Solar panel technology has become very advanced over the years and there are many innovative solar panels available in the market. Some of the more popular brands include:
- SunPower
- Panasonic
- LG
- Canadian Solar
- Jinko Solar
- Trina Solar
- REC Solar
- Silfab
- Q CELLS
The year 2020 saw SunPower, Panasonic, and LG leading the industry with high levels of efficiency and competitive pricing. In most cases, the solar panels are made from monocrystalline solar cells making them more efficient at converting sunlight. They also have a more aesthetic appeal with their uniform black tint.
Comparison between Monocrystalline vs. Polycrystalline solar panels
| Monocrystalline Solar Panels for Sale | Polycrystalline Solar Panels for Sale | |
|---|---|---|
| Appearance | Uniform black tint | Blue hue with a slightly uneven texture and color |
| Material | Single high-grade silicon crystal | Multiple silicon fragments melted together |
| Cost | More expensive | Less expensive |
| Efficiency | 15 - 20% | 13 - 16% |
| Temperature Coefficient | -0.3%/°C to -0.5%/°C | -0.3%/°C to -1%/°C |
| Lifespan | 25 years or more | 25 years or more |
| Leading Brands | SunPower monocrystalline solar panels, LG monocrystalline solar panels, Panasonic, Canadian Solar, Jinko Solar, REC Solar | Hanwha polycrystalline solar panels, Kyocera, Trina Solar, Hyundai, SolarWorld polycrystalline solar panels |
Which panel type should I choose? Pros of monocrystalline solar panels vs. Pros of polycrystalline solar panels
When you are looking to install solar panels for your homes, you will have to make a choice between monocrystalline solar panels for sale and polycrystalline solar panels for sale by considering their pros and cons. There are also other factors that you need to consider. They include:
Space conditions: Where do I plan to install the panels?
The choice of a solar panel will depend on the space available for installation. If you have less space on the roof, you may want to choose a more efficient solar panel such as the monocrystalline ones. The higher may be worth it since you will be maximizing the electricity output. If, on the other hand, you are installing it on the ground or have a lot more room on the roof, it may be more economical to choose the polycrystalline solar panel.
What are the climate circumstances in my area?
If you live in the hotter regions and face hot climatic conditions, you may be better off with monocrystalline solar panels as they tolerate more heat. There is a likelihood of a lower lifespan of polycrystalline solar panels in hot regions, especially in a desert climate.
What are the financing options? What are the differences between them?
The best monocrystalline solar panels or the best polycrystalline solar panels may not sometimes fit in your budget. You may need to compare brands and their respective prices before making your choice. Installing solar panels will require an initial investment and there are solar loans available. There are also solar leasing options.
Solar Loans
If your monthly savings on electricity bills is going to be greater than the monthly loan repayment, solar loans will be a good choice. Solar loans will offer a similar structure as in your home improvement loans. You may also have access to subsidized solar loans in certain parts of the country with low-interest rates. Buying your solar panel system outright may get you certain incentives and tax breaks.
Solar Lease or Power Purchase Agreement
You can choose solar or power purchase leases which is similar to renting the solar system. The third-party owner of the solar panel system will accept a below-market rate for the duration. A lease or power purchase agreement (PPA) can help you save up to 30% each month on your electricity bills and there won’t be any upfront cost involved. The third-party owner is also responsible for the maintenance. At the end of the lease period, you may have the option to purchase it at market price or have them remove it from your property.
Other individual preferences
Personal preferences when choosing solar power systems will depend on appearance, brand name, and pricing (solar loans versus solar leases). Best monocrystalline solar panels have a uniform black tint, whereas best polycrystalline solar panels have uneven shades of blue. You may have a favorite brand known for its quality or you may choose a particular brand for its affordability.
Going deep into the solar panel world: What are other technologies?
There are many advanced solar panel technologies that have come into existence in the solar world and innovation in these areas continues.
PERC Cell Solar Panels
PERC (Passivated Emitter and Rear Cell) technology is becoming increasingly popular. PERC cells have an additional layer, the passivation layer under the solar panel. This acts as a mirror and will reflect the sunlight that slips through the panel. PERC technology also allows for higher absorption of radiation making it more efficient.
Bifacial Solar Panels
Bifacial solar panels contain conductive material on both sides of the panel. This, in turn, maximizes the panel’s efficiency in reflecting sunshine. Bifacial collar panels must be mounted in a raised position to make the most of both sides of the panel. It is best if the roofing below the panel contains good reflective material. Currently, the installation of a bifacial solar panel is more expensive.
Half-Cut Cell Solar Panels
The size of the solar cells is cut in half and they are, therefore, smaller in size providing increased efficiency. The size of these cells is half of the conventional solar cells and will produce half of the electrical current, thereby reducing resistance and making them more efficient.
Half-cut solar cells also have a higher tolerance of shade. The cell’s efficiency will be compromised if shade falls on them and will affect the other cells in that series. There will be a considerable loss of production from the solar panel. Since the half-cut cells are differently wired, the production loss can be minimized.
Flexible Solar Panels
Apart from the usual monocrystalline vs. polycrystalline solar panels, there is a solar technology called flexible solar panels. They can be manufactured as crystalline flexible panels or thin-film panels. Thin-film panels have a thin layer of conductive material placed over a glass-based plate or over plastic.
While flexible solar panels are less expensive, they are also considered less efficient. If you do not have any space constraints, flexible solar panels may be the right choice for you.
Solar PV Shingles
Solar photovoltaic shingles or Solar PV shingles are the most practical innovations and are becoming increasingly popular. Solar PV singles can clone the appearance and function of the more traditional roofing materials such as slate or asphalt. They allow you to enjoy the aesthetics as well as the efficiency of solar power. What’s more, such solar roofing may increase the value of your home and at the same time, provide excellent solar energy.
Transparent Solar Panels
Transparent solar panels are an innovation to produce solar power from your glass windows, be it in your homes or offices. This innovation involves a transparent luminescent solar concentrator (TLSC) that transforms glass windows into solar panels.
Transparent solar panels are yet to become commercially viable and therefore, are something to look forward to in the future. Such panels will become a part of homes and offices that have large glass windows replacing the current conventional glass windows. Every building can be transformed into a solar power generator while remaining aesthetically appealing.
Final Word
Solar power has been around for a long time and is likely to continue to be the most sustainable form of energy available on the planet.
With the advanced solar technologies and the continuing research into creating solar panels that are more efficient, resilient, and more affordable which is vital when taxes, gas prices, and food costs are increasing because of current policy, it makes sense to use solar power in homes and offices as far as possible.
Tapping into the available solar energy and using innovative technologies is going to make our world more sustainable. There are already many viable options of solar panels available in the market. All you need is a little research and cost-benefit comparisons among the various brands in terms of efficiency and affordability, and choose a solar panel that matches perfectly with your needs.
