Installation cost, aesthetics of your roof and how efficient your energy generation is different from one type of solar to another. Thus, understanding each type of solar panel and what it has to offer will be beneficial in helping you decide which is best suited for your roof. With that in mind, here’s our comprehensive guide to the different types of solar panels in Singapore.
What are the types of solar panels available in Singapore?
There are 3 main types of solar panels available in the Singapore solar market today. They are monocrystalline, polycrystalline and thin-film solar panels.
Each type has its pros and cons and is made in its own unique way. Check your a quick summary of their differences below!
Traditional first-generation solar panels are usually made of monocrystalline and polycrystalline silicon. On the other hand, second-generation ones, made using innovative technology, are thin-film solar panels.
Given the different materials and manufacturing methods, the outer appearance of each type of solar panel is different. While some solar panels are black out-of-the-box, they can often appear to be blue or have a bluish hue when seen from a distance. This colour difference happens when light interacts with the different panels. Let’s take a look at the different appearances of the panels now!
The characteristic appearance of the monocrystalline solar panel is a dark or black exterior. The dark appearance is due to the way that sunlight interacts with the material of the solar panel. When sunlight traps sulfur atoms in the silicon it causes these solar panels to appear dark. Although you can’t change the colour of monocrystalline solar cells, their frames and back sheets are highly customisable. Pick from a range of designs and colours when you get solar panels of this type in Singapore. The most popular solar frame options are black and silver while the back sheets are commonly black, silver or white.
Additionally, monocrystalline panels are square-shaped, with rounded edges and their corners removed, causing small gaps between each cell.
Unlike monocrystalline cells, polycrystalline cells are marbled and blue. During the manufacturing process, the sunlight reflecting off the crystal fragments causes a blue, speckled appearance. Just like monocrystalline cells, you can also choose from various different back sheet and frames for polycrystalline options. Often, the solar frames are silver and the back sheet is silver or white. Polycrystalline cells are also square with no gaps or spaces between them.
Thin-film solar panels tend to be solid black, but can also come in both blue and black shades, dependent on the material used during manufacturing. As the name suggests, they are significantly thinner compared to the other solar panels. Cells within the panels are approximately 350 times thinner than the crystal cells used in both monocrystalline and polycrystalline panels. Being thin is the greatest aesthetic advantage that it has over the other two solar panels.
Material of Solar Panels
The material of solar panels are made from a semiconductor material, to convert light energy into electricity. Silicon is the most commonly used semiconducting material during the manufacturing process.
Monocrystalline & Polycrystalline
Both monocrystalline and polycrystalline solar panels are made from silicon, specifically silicon wafers. These wafers are aligned and assembled forming a rectangular panel. Afterwhich, they are coated with a glass sheet and mounted with a metal frame.
Despite both types of solar panels being made from silicon, the process and silicon composition are different. Monocrystalline panels are formed using the Czochralski method, by setting a pure silicon crystal into a tank of molten silicon at high temperature. The end result of this process is thinly sectioned silicon sheets or wafers. These sheets are then made into the solar cell and put together to form one solar panel.
On the other hand, instead of one raw silicon cell, polycrystalline panels are made from multiple crystals.
Just like monocrystalline cells, a silicon crystal is placed into a tank of molten silicon. However, instead of removing the crystal, the silicon is left to fragment and cool. The cooling process will result in the formation of many crystals in the mold. Once cooled, the new fragmented crystal is sliced into wafers and assembled rectangularly to form a polycrystalline panel.
Thin-Film solar panels are not always made from silicon. Made with a variety of materials, thin-film solar panels are produced by placing a thin layer of one or more films of photovoltaic matter onto a solid substrate surface. Examples of these photovoltaic materials include silicon, cadmium, copper and dye-sensitised solar cells. The most widely available thin-film solar panel is made from cadmium telluride (CdTe). During manufacturing, a layer of CdTe will be placed between layers of transparent conductors to capture sunlight. A glass layer is placed on top of the other layers as protection.
While different types of materials result in different forms of solar panels, they still fall under the category of thin-film solar cells. Due to the simplicity of the manufacturing process, the panels tend to be lightweight and flexible.
Efficiency and Performance
Of all the panels, monocrystalline solar panels have the highest efficiency of approximately 20%. This is due to them containing the highest purity of silicon among all solar panel types. These panels are crafted from a single silicon crystal, thereby allowing for faster electron flow between cells. They are also more durable and can withstand high temperatures, making them one of the most suitable types of solar panels in Singapore. Overall, these panels generally contain 60 to 72 solar cells and are some of the most efficient on the market.
Although polycrystalline solar panels are relatively new in the solar industry, they are increasingly popular and efficient. 60 to 72 solar cells are also needed to form one panel.
Due to the fragmented nature of the silicon crystals, it is more difficult for electrons in each solar cell to flow through. This polycrystalline structure causes it to have an efficiency rate of approximately 15 to 17%, lower than that of monocrystalline panels. However, recent quality improvements have improved a standard 60 cell panelfrom 240 watts to above 300 watts.
The thin-film technology is known for having the lowest efficiency of all solar panel technologies. Thin-film panels tend to have efficiencies between 10-13%, regardless of the material used during manufacturing.
As thin-film technology does not come in uniform sizes, unlike monocrystalline and polycrystalline that comes in the standard 60 to 72 solar cells, the energy capacity is largely dependent on the physical size of the panels. This means that to produce equal amounts of energy as a monocrystalline and polycrystalline panel, more thin-film solar panels will have to be installed.
Due to the manufacturing process of monocrystalline solar panels, the Czochralski process, monocrystalline panels are significantly more expensive than other panels. This is because the entire process is energy intensive and uses a pure silicon crystal which is expensive by itself.
As polycrystalline solar panels are made by melting pure whole silicon crystals, it is a faster and cheaper process compared to the Czochralski method of monocrystalline panels. Thus, it is cheaper to produce. Due to its affordability, polycrystalline panels began making up a large portion of the market share for residential installations from 2012 to 2016.
However, as a result of the shorter lifespan and efficiency of polycrystalline panels, buyers have been increasingly choosing monocrystalline panels over the years.
While they have low performance, Thin-Film panels also have the lowest cost of all solar panels. The ease of installation of these panels compared to the other panels also help to lower installation costs. However, they are known to have shorter lifespans and degrade faster, which results in more frequent maintenance and replacements needed, as well as extra costs.
So, which of these solar panel types are the best for you?
Choosing which panel is best for your installation depends on the type of property you have and your specific needs and situation. With each of these panels having its own pros and cons, it is important to consider the space that you have and the efficiency you require to cover your day time needs.
Among the three types of panels, the monocrystalline panels are most popular among residential solar installations in Singapore. As they are space-efficient, they can be easily installed onto residential rooftops. Also, they often have a long lifespan and function well beyond the given warranty period. This makes it a better value for money option for homeowners looking to embark on the solar journey.
However, if you are on a tight budget, you can consider polycrystalline panels instead, which are less expensive than monocrystalline panels. Polycrystalline panels can be utilised in both small and large scale projects and installations due to the wide range of power capacity that they come in. If you are thinking of installing polycrystalline solar panels onto your rooftops, do take note that due to it being less efficient, you may require a larger surface area as compared to monocrystalline panels to satisfy your energy needs.
Thin film solar panels are completely different from the first generation solar panels. Being an extremely fresh development, they are often not the best option for residential solar. Mostly, they are used in industrial solar installations or other large scale operations, as the residential roof is unable to withstand the weight of the large equipment. Also, as these areas are larger in size, they have sufficient space to install more solar panels to fulfil their energy needs.
Before deciding on which solar panel is right for you, you should also check if your roof is suitable for installing solar panels. If you have a flat roof, thin-film solar panels would be highly suitable as they are flexible and can be modified into automatic panels. Automatic panels follow the sunlight throughout the day, maximising the amount of sunlight being absorbed. Although they are less efficient compared to monocrystalline and polycrystalline solar panels, they may be able to produce more electricity on a flat roof.
This article was first published on 27 October 2020 and last updated on 30 April 2021 to include additional details.
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