Kemaskini: 17 Sep 2019
There are hundreds of companies manufacturing solar panels today. Most of the solar panel options currently available fit in one of three categories: monocrystalline, polycrystalline (also known as multi-crystalline), or thin-film. These solar panels vary in how they are made, appearance, performance, costs, and the installations each are best suited for.
Which one is the most suitable to my house or business? It depends on how you install it on site. The type of installation is playing a crucial role to assist you to choose a more suitable type of solar panels.
Pros and Cons of Different Type of Solar Panels
Generally, the types of solar panels are monocrystalline, polycrystalline, and thin-film panels. Each type has its own unique advantages and disadvantages, and the solar panel type best suited for your installation will depend on factors specific to your own property and desired system characteristics.
Below, we will break down some common questions and concerns about solar panels and how different types of panels have varying characteristics.
What Are They Made of?
In order to generate electricity, solar cells are made from a semiconducting material that converts light into electricity. Silicon is the most common semiconducting material used during the solar cell manufacturing process.
Monocrystalline & Polycrystalline Solar Panels
Solar cells of both monocrystalline and polycrystalline solar panels, are made of silicon wafers. In order to build a monocrystalline or polycrystalline solar panel, wafers are assembled into rows and columns to form a rectangle, covered with a glass sheet, and framed together.
Even though solar cells of both types of solar panels, are made from silicon, they vary in the composition of the silicon itself. Monocrystalline solar cells are cut from a single, pure crystal of silicon. On the other hand, polycrystalline solar cells are composed of fragments of silicon crystals that are melted together in a mold before being cut into wafers.
Thin-Film Solar Panels
Unlike monocrystalline and polycrystalline solar panels, thin-film panels are made from a variety of materials. The most prevalent type of thin-film solar panel is made from cadmium telluride (CdTe). Manufacturers have to place a layer of CdTe between transparent conducting layers so it can capture the sunlight. This type of thin-film technology also has a glass layer on the top for protection.
Secondly, thin-film solar panels can also be made from amorphous silicon (a-Si), which is similar to the composition of monocrystalline and polycrystalline solar panels. Unlikely, they are not made up of solid silicon wafers as monocrystalline and polycrystalline solar panels. They are composed of non-crystalline silicon placed on top of glass, plastic, or metal.
Lastly, Copper Indium Gallium Selenide (CIGS) panels are another popular type of thin-film technology. CIGS panels have all four elements placed between two conductive layers (i.e. glass, plastic, aluminum, or steel), and electrodes are placed on the front and the back of the material to capture electrical currents.
How to Differentiate The Type of Solar Panels
The differences in materials and production cause differences in appearance between each type of solar panel:
Monocrystalline Solar Panels
If you see a solar panel with black cells, it is most likely a monocrystalline panel. This is because of the way light interacts with the pure silicon crystal. Thus, it appears black in color. However, monocrystalline solar panels have a variety of colors for their back sheets and frames. The back sheet of the solar panel will most often be black, silver or white, whereas the metal frames are typically black or silver.
Polycrystalline Solar Panels
Polycrystalline solar cells tend to have a blue hue to them due to the light reflecting off the silicon fragments in the cell in a different way than it reflects off a pure monocrystalline silicon wafer. Similarly to monocrystalline, polycrystalline panels have different colors for back sheets and frames. The frames of polycrystalline panels usually are silver, and the back sheets are either silver or white.
Thin-film Solar Panels
The biggest differentiating aesthetic factor when it comes to thin-film solar panels is how thin and low-profile the technology is. As their name suggests, thin-film panels are often slimmer than other types of panel. This is because the cells within the panels are roughly 350 times thinner than the crystalline wafers used in monocrystalline and polycrystalline solar panels. It is important to keep in mind that while the thin-film cells themselves may be much thinner than traditional solar cells, an entire thin-film panel may be similar in thickness to a monocrystalline or polycrystalline solar panel if it includes a thick frame. There are adhesive thin-film solar panels that lie as-close-as-possible to the surface of a roof, but there are more durable thin-film panels that have frames up to 50 mm thickness.
What Are The Bifacial Solar Panels?
Bifacial solar panels can capture sunlight from both the front and back of the panel. Therefore, they are able to produce more electricity than comparably sized, traditional solar panels. Many bifacial solar panels will have a transparent back sheet so that sunlight can go through the panel, reflect off the ground surface and back upwards towards the solar cells on the back side of the panel. These solar panels are typically manufactured with monocrystalline solar cells, but polycrystalline bifacial solar panels exist as well.
Solar Panels Power and Efficiency Ratings
Different type of solar panels will vary the amount of power generated.
Monocrystalline and Polycrystalline Solar Panels
Among all types of solar panels, monocrystalline solar panels typically have the highest efficiencies and power capacity. Most monocrystalline solar panels often reach efficiencies higher than 20%, while polycrystalline solar panels usually have efficiencies between 15% to 17%.
Monocrystalline solar panels tend to generate more power than other types of panels not only because of their efficiency because they have come in higher wattage modules as well. Many monocrystalline solar panels come with more than 300 watts (W) of power capacity, some reaching more than 350 W. In contrast, polycrystalline solar panels tend to have lower wattages.
This does not mean that monocrystalline and polycrystalline solar panels are not physically the same size. In fact, both types of solar panels tend to come with 60 silicon cells each, with 72 or 96 cell variants (usually for large-scale installations). However, even with the same number of cells, monocrystalline solar panels are capable of producing more electricity than polycrystalline solar panels.
Thin-film Solar Panels
Thin-film solar panels tend to have lower efficiencies and power capacities than monocrystalline or polycrystalline solar panels. Efficiencies will vary based on the specific material used in the cells, but they usually have efficiencies closer to 11%.
Unlike monocrystalline and polycrystalline solar panels that come in standardized 60 and 72 cell variants, thin-film technology does not come in uniform sizes. As such, the power capacity from one thin-film panel to another will largely depend on its physical size. Generally, the power capacity per square meters of monocrystalline or polycrystalline solar panel will exceed thin-film panel technology.
How Much Are They?
The processes of manufacturing are different between monocrystalline, polycrystalline, and thin-film. As a result, each type of panel comes with a different price tag.
Monocrystalline Solar Panels
Among all types of solar panels, monocrystalline panels are likely to be the most expensive option. This is probably due to the process of manufacturing. Their solar cells are made from a single silicon crystal. Thus, manufacturers have to absorb the costs of creating these crystals. This process, known as the Czochralski process, is energy intensive and results in wasted silicon (that can later be used to manufacture polycrystalline solar cells).
Polycrystalline Solar Panels
Polycrystalline solar panels are typically cheaper than monocrystalline solar panels. This is because the cells are produced from silicon fragments rather than a single, pure silicon crystal. This allows for a much simpler cell manufacturing process. Hence, the cost is lesser for manufacturers and eventually end users.
Thin-film Solar Panels
Thin film solar panels have different price which depends on what materials made of. CdTe is generally the cheapest type of solar panel to manufacture. On the other hand, CIGS solar panels are much more expensive to produce than both CdTe or a-Si.
Regardless of the cost of the panel themselves, the overall cost of a thin-film solar panel installation may be lower than installing a monocrystalline or polycrystalline solar panel system due to additional labor requirements. Thin-film solar panel installations are less labor-intensive because they are lighter weight and more maneuverable. Making it easier for installers to carry panels up onto rooftops and secure them in place. This means reduced labor costs, which can help contribute to an overall less expensive solar panels installation.
Make Your Choice for Your Installation
Monocrystalline, polycrystalline and thin-film solar panels have their own pros and cons. The solution you should move forward with depends on your property and your goals for the solar energy project.
Property owners with a lot of space for solar panels can save money upfront by installing lower efficiency, lower-cost polycrystalline panels. If you have limited space available and are looking to maximize your electric bill savings, you can do so by installing high-efficiency, monocrystalline solar panels.
As far as thin-film panels go, it is the most common to choose this type of solar panel if you are installing on a large, commercial roof that cannot handle the additional weight of traditional solar equipment. These types of roofs can also afford the lower efficiencies of thin-film panels because they have more area to place them on. In additional, thin-film panels can sometimes be a useful solution for portable solar systems, like on floating platform or boats.