Polycrystalline Solar Panel: Definition, How it Works, and Features

Polycrystalline, multicrystalline, or poly solar panels are a type of photovoltaic (PV) panel used to generate electricity from sunlight. They are the second most common residential solar panel type after monocrystalline panels. Polycrystalline panels provide a balanced combination of efficiency, affordability, and durability, making them a popular choice for commercial and industrial uses. The term polycrystalline is derived from its cell structure, which contains multiple (“poly”) silicon crystals (“crystalline”). This contrasts with monocrystalline cells, which use a single (“mono”) silicon crystal.

Polycrystalline panels are easy to distinguish from their blue hue and specked appearance, which is caused by the way that light interacts with fragments within the cell. The fragmentation within the cell structure impacts the efficiency of polycrystalline panels, producing 13-16% efficiency compared to the higher 15-25% efficiency of monocrystalline. This slightly lower efficiency is caused by the polycrystalline manufacturing process, which involves melting silicon fragments into molds rather than the more difficult and expensive process of creating single silicon crystals for monocrystalline panels. The formation of multiple crystal structures within a single polycrystalline cell creates boundaries that impact the free flow of electrons, slightly lowering their efficiency.

One of the main advantages of polycrystalline solar panels is their affordability. Poly panels are cheaper to produce and are in less demand within the residential solar industry. Typically, a polycrystalline panel costs around $0.75-$1 per watt. One of the main disadvantages of polycrystalline panels is that, due to their lower efficiency, they require more space to produce the same output as monocrystalline panels. For this reason, polycrystalline panels are better suited for commercial and industrial applications such as solar farms, where space is typically less limited. Other common applications of polycrystalline panels include integration on boats and campervans. Poly panels are durable and able to withstand harsh weather conditions. They have a lifespan of up to 35 years.

As solar panel prices continue to decline in general, polycrystalline panels are becoming less popular. The residential solar market has primarily switched to monocrystalline panels, and increasingly the industrial market is following suit.

What is a Polycrystalline Solar Panel?

A solar panel is a device used to capture sunlight for conversion into electricity. Polycrystalline panels, the second most common solar panel type, are named for the multiple crystals that make up their cells. Slightly less efficient than monocrystalline panels due to their less uniform cell structure, they offer an affordable alternative to monocrystalline panels and are blue rather than black.

One of the distinguishing features of polycrystalline (poly) solar panels is their unique silicon cell structure. In polycrystalline solar cells, silicon crystals are melted and fused together, resulting in a less uniform structure than monocrystalline solar cells. When light interacts with polycrystalline cells, it reflects off the non-uniform silicon crystal structure, giving the panels a characteristic bluish hue and speckled appearance.

While easier and more cost-effective to produce, polycrystalline cells have a slightly lower efficiency rate of 13-16% compared to monocrystalline ones at 15-25%. This is because the boundaries between the silicon crystals in polycrystalline cells impede the flow of electrons, reducing the overall efficiency of the solar panel.

The main benefit of polycrystalline panels is their affordability. Poly panels are cheaper than monocrystalline in part due to their less demanding manufacturing process. Another factor is that their slightly lower efficiency makes them less sought after for residential photovoltaic (PV) systems, where space is limited and higher-efficiency panels are generally preferred. Typically, a polycrystalline solar panel is priced between $0.75 to $1.50 per watt. For a standard 6kW solar panel system, this translates to a cost of around $4500 to $9000. Their lower price point makes polycrystalline solar panels an attractive option for those looking for a more cost-effective solar solution.

Polycrystalline panels have a range of applications, including residential solar systems, commercial solar systems, solar farms, and off-grid systems. In residential settings, polycrystalline panels are often used as roof-mounted arrays, providing a cost-effective way to reduce reliance on grid-supplied power. In commercial applications, such as office buildings and factories, polycrystalline panels are mounted on rooftops or as part of solar carports, offering both energy and shade for vehicles. Solar farms are an ideal application for polycrystalline panels because they have sufficient space to install a large amount of panels while maximizing their cost efficiency. Some off-grid systems, such as remote communication stations and cabins, use polycrystalline panels to provide reliable and sustainable power in remote locations.

How do Polycrystalline Solar Panels work?

Polycrystalline solar panels work by using multicrystalline silicon cells to absorb sunlight and convert it into electricity. This is a result of the photovoltaic effect, where electrons within the cells of the panel are knocked loose as a direct result of contact with sunlight. The electrons form a direct current (DC) that can be converted to alternating current (AC) with an inverter, powering homes and businesses.

Polycrystalline PV panels are crafted from silicon crystals that are melted together, creating a less uniform structure compared to monocrystalline panels. This production method makes them somewhat less efficient in conducting electricity. Polycrystalline panels typically have a square cell pattern, which doesn’t offer as large a surface area as the pyramid cell pattern of monocrystalline panels. As a result, they don’t collect energy from the sun's rays as efficiently as monocrystalline panels.

The benefit of the polycrystalline manufacturing process is that it is less complex and cheaper compared to the delicate process of creating single crystals for monocrystalline cells. Silicon is a very expensive material, and by requiring lower purity than monocrystalline cells, less wastage is required of the process as well. In some cases, the silicon that’s melted together for polycrystalline cells is sourced from leftover wastage from monocrystalline manufacturing.

What are the Features of a Polycrystalline Solar Panel?

The seven main features of polycrystalline solar panels are their multicrystalline cell structure, speckled blue appearance, 13-16% efficiency, larger space requirement, moderate tolerance to heat, durability, and lower cost.

More information on the seven main features of polycrystalline panels is given below.

• Multicrystalline Cell Structure: Polycrystalline solar panels use multicrystalline solar cells, which are made by melting together multiple silicon fragments. The advantage of this cell structure is that the manufacturing process is cheaper and more efficient. On the downside, the cells produced through this process are slightly less efficient compared to other cell types like monocrystalline.
• Speckled Blue Appearance: Polycrystalline panels have a distinctive blue look, which makes them easy to distinguish from other panel types, like monocrystalline ones, which are black. The blue color of poly panels is a result of their cell structure.
• Efficiency of 13-16%: The efficiency of polycrystalline panels is high, at 13-16%, but is still lower than some other solar panel types. Polycrystalline panels are therefore ideal for larger installations, where a cheaper, but slightly less efficient panel than monocrystalline is ideal for space and budget requirements.
• Greater Space Requirement: Polycrystalline panels require more space, largely because they are less efficient. In other words, more space is required to generate the same amount of energy compared to other panel types. This makes them an ideal choice for industrial applications.
• Moderate Tolerance to Heat: Polycrystalline solar panels demonstrate a moderate tolerance to heat, meaning that their efficiency only slightly decreases if temperatures rise above 77 degrees Fahrenheit (°F). They operate optimally within a temperature range of 90 to 122°F, making them suitable for various climates.
• Durability: Polycrystalline solar panels are known for their strength and long-lasting structure. They are made from multiple silicon cells, which have undergone a process known as solidification, creating boundaries between the crystal fragments. These boundaries prevent cracks in the structure and maintain the structural integrity of the panel. Due to their durability, polycrystalline solar panels usually last for 20-30 years and beyond. However, this lifespan is affected by poor maintenance, inefficient manufacturing quality, and environmental conditions.
• Lower Cost: Polycrystalline solar panels are generally more affordable than monocrystalline panels. The current market price for polycrystalline panels is around $0.50-$1.0 per watt. This implies that a 400-watt panel would cost around $150-$400. The lower price point of polycrystalline panels makes them an attractive option for those seeking a cost-effective solution for solar energy. While the initial cost of polycrystalline solar panels is lower, other factors, such as the cost of installation and efficiency, must be taken into account when assessing the overall value for money of a solar energy system.

What are Some Common Applications of Polycrystalline Solar Panels?

There are four main applications of polycrystalline solar panels. The most common application of polycrystalline panels is residential solar systems. In fact, polycrystalline panels are the second most common photovoltaic (PV) panel type found in households worldwide. The three other main applications of polycrystalline panels are Commercial Solar Systems, Solar Farms, and Off-Grid Systems.

Below is more information on the four main applications of polycrystalline solar panels.

• Residential PV systems: Residential PV systems include the installation of polycrystalline solar panels in homes. Commonly used as roof-mounted solar arrays, polycrystalline solar panels are a popular choice for homes due to their cost-effectiveness. Polycrystalline solar panels in residential properties capture optimal sunlight and convert it into electricity for home use, reducing the reliance on grid-supplied power. Their vibrant blue hue and square shape make them aesthetically pleasing, while their efficiency makes them an ideal choice for residential PV systems. Since they require sufficient space to be effective due to their sizes, polycrystalline solar panels are commonly found on large residential arrays.
• Commercial PV systems: Polycrystalline solar systems are suitable for commercial applications, such as office buildings, factories, warehouses, solar carports, and parking structures. In office buildings, polycrystalline panels are usually mounted on their roofs to serve as a green solution to energy expenses. In factories, polycrystalline solar panels are installed to power machinery and lightning. Polycrystalline solar panels are set atop parking structures to offer shade for vehicles and generate a source of renewable energy. Commercial PV systems usually install polycrystalline solar panels on large rooftops to generate substantial energy to power business operations and possibly contribute to the grid's power needs.
• Solar Farms: Large solar farms often employ polycrystalline solar panels to capture optimal amounts of energy on a significant scale due to their durability and cost-effectiveness. These farms are usually expansive areas, and the power generated by these expansive areas is subsequently distributed to surrounding regions, contributing to the renewable energy supply of the grid. This energy distribution decreases the dependence on fossil fuels by transforming sunlight into electricity on a large scale.
• Off-Grid Systems: Standalone systems like remote communication stations or cabins use polycrystalline solar panels to transform sunlight into usable power through the photovoltaic effect, where solar energy causes electrons in a solar cell to move. In remote forest-based cabins, polycrystalline solar panels power lights, charge devices, and even run small appliances. In remote communication systems, polycrystalline solar panels provide the necessary power to keep the communication equipment running. In water pumping systems, polycrystalline solar panels are used to provide a reliable and sustainable solution for irrigation.

Other smaller applications of polycrystalline panels include powering street lights, water pumps, and other standalone systems that require reliable and renewable energy sources.

Are Polycrystalline Solar Panels Good for Campervans?

Yes, polycrystalline solar panels are good for campervans, producing a respectable conversion efficiency of 13-16%. Whilst not as efficient as monocrystalline panels, meaning they require more space, poly panels are a budget-friendly and durable option to install on your camper roof.

Monocrystalline panels are usually the best choice for a campervan overall. While more expensive than polycrystalline panels, they produce a higher efficiency of between 15-25%, meaning that fewer of them are required for the same output. This is an important consideration for a campervan or RV roof where space is usually limited. Ultimately, choosing solar panels for campers comes down to balancing cost, space availability, and efficiency requirements.

Are Polycrystalline Solar Panels Good for Residential Homes?

Yes, polycrystalline solar panels are suitable for residential installations. In fact, polycrystalline is the second most common panel type used in homes. Polycrystalline panels have a moderate efficiency of 13-16%, which is less than monocrystalline (meaning they require more space to produce the same power). However, the major benefit of poly panels is that they are highly affordable.

The major drawback of using polycrystalline panels for your home is that their lower efficiency translates to a greater space requirement. In contrast, monocrystalline panels offer higher efficiency, meaning they provide more power using less space for the panels. However, polycrystalline panels have the advantage of being highly affordable at $0.75-1.50 per watt, compared to monocrystalline panels at $1.0-$1.50 per watt.

Whether you choose between polycrystalline or monocrystalline panels for your home solar panel system depends on your exact needs. In most cases, it’s best to consult with your solar installer to determine what best suits your needs. While thin-film panels are becoming more prevalent, their limitations make them less likely to be used for residential purposes.

Is Polycrystalline the Most Efficient Type of Solar Panel?

No, polycrystalline is not the most efficient solar panel type. Polycrystalline panels have around 13-16% efficiency, which is less than some other types like monocrystalline, which are the most efficient panel at 15-25% efficiency. This means that more poly panels are required to produce the same amount of energy as mono ones. Poly panels require more space but are cheaper.

Like most solar panel types, the efficiency of polycrystalline PV panels declines with increasing temperatures. A panel's temperature coefficient (measured in % per °F) refers to how the efficiency of a panel is reduced by each degree Fahrenheit over a specific reference point. Polycrystalline panels have a -0.3% to -1% temperature coefficient range, which is slightly higher than monocrystalline panels. This means that polycrystalline panels are slightly more affected by increases in temperature compared to monocrystalline panels.

What are the Advantages of Polycrystalline Solar Panels?

The four main advantages of polycrystalline solar panels are outlined below.

• Affordability: Polycrystalline solar panels offer a cost-effective solution for harnessing solar energy. At an average cost of $0.75 to $1.50 per watt, poly panels are a cheaper alternative to popular alternatives like monocrystalline panels, at $1-$1.50 per watt. This is owed to the differences in manufacturing processes involved. Polycrystalline panels are simply made by melting and pouring raw silicon into molds, whereas monocrystalline panels are complex and costly to manufacture due to the high purity of silicon required, which creates silicon wastage.
• Lower Waste: Polycrystalline panels require less energy and silicon to manufacture, and often use recycled material from the monocrystalline panel manufacturing process. This makes poly solar panels an environmentally conscious choice because of their ability to harness renewable energy and promote overall waste reduction.
• Versatility: Another advantage of polycrystalline panels is that they are suitable for a wide range of applications, from residential solar installations to commercial and industrial projects. Poly panels are commonly used to power solar farms and standalone devices such as traffic lights in remote areas and off-grid devices. In addition, polycrystalline solar panels are durable, cost-effective, long-lasting, and perform under various conditions, making them a suitable option for industrial, commercial, and residential applications.
• Durability: Polycrystalline solar panels are highly durable due to the quality of the materials employed in their manufacturing process. Made from silicon, they can withstand harsh weather conditions such as snow, rain, and hail. In addition, polycrystalline panels typically have a lifespan of around 25 years and more, making them a cost-effective green energy solution.

What are the disadvantages of Polycrystalline Solar Panels?

The three main disadvantages of polycrystalline solar panels are below.

• Space Requirements: Due to their larger size, polycrystalline solar panels require more roof space than other solar panel types. Specifically, polycrystalline solar panels are available in a variety of sizes, with the most common being 65x39 inches or 66x40 inches, with 1.5 inches thickness corresponding to a 60-cell panel layout for residential installation. However, the size of polycrystalline panels varies based on their specific power output and applications. For instance, commercial installation usually requires larger solar panels, measuring around 77 by 39 inches, indicating a 72-cell panel layout. This means many homeowners and business owners are not likely to have enough space on their roofs to install the number of panels they need to power their home or business efficiently.
• Lower Temperature Coefficient: The temperature coefficient of a solar panel is a measure of how much its efficiency decreases with each degree increase in temperature above 25°C (77°F). Polycrystalline panels have a lower temperature coefficient than monocrystalline panels, making them slightly less effective beyond a certain temperature threshold. Polycrystalline solar panels generally have a temperature coefficient in the range of -0.3% to -1% per degree Fahrenheit. This means that their efficiency drops more significantly as temperatures rise, compared to the -0.3% to -0.5% per degree Celsius of monocrystalline panels. Furthermore, prolonged exposure to high temperatures shortens the lifespan of multicrystalline panels.
• Lower Efficiency: Polycrystalline panels capture sunlight at an efficiency of 13-16%. This energy conversion rate is still respectable, although less than monocrystalline at up to 25% efficiency. This difference between monocrystalline and polycrystalline is due to the lower silicon purity and less ordered structure used in poly panels. However, this means that polycrystalline solar panels offer a good balance between budget and energy efficiency.

What is the Average Price of a Polycrystalline Solar Panel?

The average price of a polycrystalline solar panel ranges from $0.75 to $1.50 per watt. For a typical residential solar system in the United States, which requires between 5 and 7 kilowatts (kW), this translates to a total system cost ranging from $3,750 to $10,500. However, the cost of polycrystalline panels varies based on factors such as the manufacturer, the size and wattage of the panel, the quantity purchased, any additional features or certifications, and the location of purchase. Other factors that impact the cost of polycrystalline panels include the complexity of the installation, any additional hardware needed, and local incentives or rebates.

What is the Difference Between Polycrystalline and Monocrystalline Solar Panels?

There are a number of significant differences between monocrystalline and polycrystalline panels. Monocrystalline panels are made from single-crystal silicon, giving them a higher efficiency level and black appearance. Polycrystalline panels are made from multiple silicon fragments, making them slightly less efficient but more cost-effective, with a blue hue. The underlying difference between polycrystalline and monocrystalline solar panels is their cell structure. Other key differences include their efficiency level, cost, lifespan, space requirement, manufacturing process, and appearance. More information on the seven main differences between polycrystalline and monocrystalline panels is below.

• Cell Structure: Polycrystalline panels use multiple silicon fragments to make up a single cell, whereas monocrystalline panels use a highly pure, single-cell structure. This underpins other differences between these two panel types, such as their differing appearance, efficiency, and manufacturing process.
• Efficiency: Monocrystalline panels have an efficiency rate between 16-23%, whereas polycrystalline panels operate at an efficiency of 13-16%. Because monocrystalline panels are made of pure silicon, they are more efficient than polycrystalline panels.
• Cost: Polycrystalline solar panels typically cost around $0.40 per watt, making them a cheaper alternative to monocrystalline panels, which usually cost around $0.75 per watt. Monocrystalline panels, however, offer a quicker return on investment because of their higher efficiency rating.
• Lifespan: Both monocrystalline and polycrystalline panels have a similar lifespan, usually around 25 years. Monocrystalline panels are usually more durable than polycrystalline panels and withstands harsh weather conditions and high temperatures better.
• Space Requirement: Monocrystalline and polycrystalline solar panels are similar in size. The typical residential solar panel size for both types is approximately 165 cm by 99 cm. However, due to higher efficiency, more polycrystalline panels are required to match the equivalent energy of monocrystalline solar panels, meaning that inevitably, more panels and space for those panels are required.
• Manufacturing Process: Monocrystalline panels are made from a single, pure silicon crystal structure. This way, the electrons, which generate electricity, are given more freedom to move. Polycrystalline panels, however, contain multiple crystal structures, which restrict electron movement and reduce their efficiency.
• Appearance: Monocrystalline solar cells are typically black due to the way light interacts with the pure silicon crystal, while polycrystalline solar cells are usually colored blue or even slightly purple due to the light reflecting off the multifaceted silicon crystals inside. Additionally, black absorbs more light than blue, enhancing the efficiency of monocrystalline solar panels.

It is important to carefully consider the pros and cons of each panel type. The choice of monocrystalline vs multicrystalline solar panels is ultimately up to the buyer, depending on individual requirements and budget. These days, residential solar is more than 95% constituted of monocrystalline panels.