ith the rise of renewables, we are experiencing a paradigm shift in how our energy is produced. While clean energy is a key to a sustainable future, it is also a great way to save money on electricity bills and improve our quality of life.
Monocrystalline solar panel vs polycrystalline: first thing to consider when going solar
If you are planning to join the global trend switch to solar, you have the challenge of choosing the right solar panels ahead of you. This article is going to give you a clear picture of a monocrystalline solar panel vs polycrystalline panel so that you can decide on which type suits you the most.
Physics behind monocrystalline and polycrystalline solar cells
Solar cells, or photovoltaic cells, are mostly made of monocrytalline silicon - the second most abundant chemical element in the earth’s crust after oxygen, making up 28%. It is a dark gray solid with a blue-gray metallic luster and has a crystal structure that resembles a diamond. Silicon can’t be found in nature in a pure form but rather as a component of silica (silicon linked up with oxygen) or silicates (silicon combined with oxygen and some other elements). It is usually found in rocks, sand, clays, and soils.
Pure silicon is produced by heating silicon dioxide with carbon at around 2200°C to be later used as a semiconductor material for solar cell production. It currently dominates the solar market due to its excellent electronic properties and affordability – around 95% of solar panels sold today are made from silicon.
Monocrystalline solar cells are fabricated from a single crystal ingot. Today monocrystalline panels account for 32% of the global solar energy market.
A polycrystalline solar cell is made by melting multiple ingots of silicon together and pouring this liquid into a mold. It is later cooled, solidified, and sliced into thin plates.
What do monocrystalline and polycrystalline solar cells look like?
As you might have noticed, solar panels come in two colors, black and blue. The color is chosen not for aesthetic reasons, it depends on the type of solar cells.
Monocrystalline panels are usually black and their solar cells have rounded corners. The black color allows a monocrystalline cell to absorb more heat from solar energy and thus operate more efficiently.
The blue solar panels are made of polycrystalline solar cells due to an anti-reflective coating that enhances their light absorption efficiency and capacity.
Is a monocrystalline solar panel more efficient?
The efficiency of a solar panel shows how much sunlight it can convert into electricity. It generally depends on many factors such as temperature, shading, irradiance level, etc. But solar cell type is another important determinant, as the efficiency of monocrystalline and polycrystalline solar cells differs significantly.
Monocrystalline panels have a higher efficiency rate, typically it ranges from 15% to 20%. Polycrystalline panels are less efficient than monocrystalline with a 13-16% efficiency rate. This is because in a polycrystalline solar cell the boundaries of the crystallites decrease the electrical conductivity and create resistance to the flow of electricity. Consequently, the panel loses a portion of the electrical output.
Do monocrystalline solar panels save more space?
Monocrystalline and polycrystalline panels have different space efficiency as well. As fewer monocrystalline panels are needed to reach a certain monthly kilowatt-hour output, you will need fewer mono cells to meet your energy demand. While monocrystalline solar cells generate approximately 190W per one square meter, polycrystalline solar cells will generate nearly 180W.
The lifespan of mono and polycrystalline solar panels
Solar panels lose from 0.3% to 1% in efficiency every year. However, you can considerably increase your PV system’s lifespan by choosing a more durable monocrystalline solar panel. Monocrystalline solar panels have a slower degradation rate, which the yearly decrease in output of a mono cell is lower. This is largely attributed to the monolithic structure of a monocrystalline cell, which makes it less prone to failure. Most monocrystalline panel manufacturers offer 25-30-year warranties, but monocrystalline panels can last for 40 years or even more.
Polycrystalline solar cells usually come with warranties of up to 20 years. However, as with monocrystalline panels, they tend to last longer than their warranty period.
Is monocrystalline solar panel less exposed to temperature changes?
There is a common misconception that the stronger the sun is, the more power a solar panel generates. But that's not actually true. Semiconductors, such as silicon, are temperature-sensitive. The temperatures beyond the optimum range can decrease the voltage of solar cells and their power efficiency. Solar panels are normally designed to function at around 77°F, or 25°C, higher temperatures can reduce the energy output of both mono and polycrystalline panels.
But still, monocrystalline solar panels are considered to be more heat-tolerant than polycrystalline panels. The temperature coefficient of monocrystalline cells typically stands at 0.36-0.40%/°C, which means the efficiency of a mono solar cell can fall by up to 0.4% for every degree above the optimal level. A polycrystalline solar cell handles high temperatures slightly worse than monocrystalline with a temperature coefficient of 0.39-0.43 %/°C.
Why is a monocrystalline solar panel more expensive?
It might seem like we already have a clear winner in the monocrystalline vs polycrystalline battle, but the price is the main cause why many people still prefer polycrystalline panels over monocrystalline ones.
Today, monocrystalline solar panels cost between $1 and $1.50 per watt. So a 6kW monocrystalline solar system will cost from $6,000 to $9,000.
Polycrystalline panels, on the other hand, are considerably more affordable than monocrystalline. The average cost of polycrystalline solar panels ranges from $0.90 to $1 per watt, which means you would pay $5,400 -$6,000 for the whole polycrystalline system.
However, you should keep in mind that higher efficiency of monocrystalline cells might be worth the higher upfront cost. Even though monocrystalline panels are costlier to install, your initial investment can is likely to pay off sooner.
Alternative to monocrystalline and polycrystalline solar panels
While monocrystalline and polycrystalline solar panels still hold the major market share, there is one more solar option that deserves to be mentioned. Thin-film cell is a second-generation solar cell that is made by applying a thin layer of photovoltaic material on top of a substrate, such as plastic, glass, or metal. These panels are flexible and lightweight, which means they can be easily shaped to fit into almost any environment.
They are also cheaper to manufacture than traditional crystalline panels, which leads to a lower selling price. Besides, thin-film solar cells are more environmentally friendly, as their manufacturing requires less silicon, which means it produces less emissions.
The main drawback of these panels is conversion efficiency, although it can greatly vary depending on the type of the basic photovoltaic material. Today it usually ranges from 7% to 18%, however, some newest versions reach over 22% efficiency, which is comparable with monocrystalline panels.
Monocrystalline vs polycrystalline solar panels: which panel type is better?
As you can see, both panel types might work for homeowners. Monocrystalline solar panels are more efficient and require less space, but are far more expensive. Polycrystalline panels are more affordable than monocrystalline options but less energy efficient and take up more space.
Monocrystalline systems can be a perfect choice for limited spaces and areas with non-permanent sunlight. Monocrystalline panels are also the best choice for those who prioritize efficiency over cost.
Polycrystalline solar panels, by contrast, are perfectly suited for larger areas with abundant sunlight. They can be a great alternative for homeowners who are looking for a budget-friendly way to go solar.