There are 3 different types of solar modules that you need to be familiar with. Each one has its own unique advantages and disadvantages that should be taken into account when deciding which type to purchase for your project. The 3 types are:
1) Mono-crystalline Silicon
2) Poly-crystalline Silicon
3) Thin Film
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Mono-crystalline solar modules are created using solid silicon ingots. This is evident in the silicon wafers that make up the energy-producing part of the module. As you can see in the image below, each square is slightly rounded at the edges. This occurs due to the manufacturing process of these highly-pure ingots. The wafers are cut out of the cylindrical ingots to make the wafers. They usually have a much more uniform, dark color to them compared to poly-crystalline modules.
1) The highest efficiency modules on the market. This is due to the wafers being made from the highest, purest silicon.
2) More space efficient. Since these modules have a higher efficiency, they take up less room per watt than any other module type.
3) Great low-light performance
1) More expensive. Since these modules use the highest grade silicon, the price for manufacturing is higher.
2) Most silicon is wasted. The silicon is manufactured in cylindrical ingots and the square wafer is cut out of it. A lot of silicon is wasted but still has to be paid for.
3) Slightly more efficient in warmer weather.
Mono-crystalline vs. Poly-crystalline solar modules
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Poly (Multi) -crystalline
These modules are manufactured slightly differently than mono-crystalline modules. The silicon is first melted into a rectangular form before the wafers are cut into squares. You can see an example of a polycrystalline module above. The wafers have right-angle corners, unlike the mono-crystalline. This is a great indicator of what type of solar module you have. The color is usually lighter and broken up more so than a mono-crystalline solar module.
1) Manufacturing is much simpler and therefore less expensive.
1) Less efficient than mono-crystalline. Since the silicon is melted and re-solidified, the silicon wafer isn't as pure as a mono-crystalline module. Poly-crystalline modules are on average ~5% less efficient than mono-cyrstalline.
2) Not as space efficient. A larger poly-crystalline module is needed to produce the equivalent amount of energy compared to a mono-crystalline module.
Thin-Film Solar Cells (TFSC)
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These modules are manufactured by layering photovoltaic material onto a substrate. The number of layers can vary. The most common photovoltaic materials are categorized by their photovoltaic material:
1) Amorphous Silicon
2) Cadmium telluride
3) Copper indium gallium selenide
4) Organic photovoltaic material
These types of solar modules are less efficient compared to mono and poly-crystalline solar modules in general.
1) Manufacturing is the easiest and cheapest.
2) Can be made for flexible applications, not just rigid solar module applications like roof-top and utility scale solar.
3) Visually appealing. Just like mono-crystalline modules, they have a very uniform look since they are a uniform material throughout.
4) If space is not an issue, these could provide a cheaper option for your solar project.
1) Take up a lot of room. This may not be as ideal for applications where space limitation is a factor.
2) More racking is needed per module. This could drive up racking and other equipment costs.
3) Degrade quicker than mono and poly-crystalline modules.