History

Since their inception, solar PV panels have been a beacon of hope in the quest for sustainable and renewable energy sources. The concept of harnessing the sun’s power for clean energy dates back to the early 19th century, but it wasn’t until 1954 that the first practical photovoltaic (PV) cell was developed by Bell Laboratories. This marked a significant turning point in our ability to convert sunlight directly into electricity.

For decades, solar panels were expensive and largely used for specialized applications such as space exploration. The technology made headlines in 1958 when it powered the Vanguard 1 satellite, the first-ever object to use solar PV cells for energy. However, as technology advanced and manufacturing processes improved, solar panels became more affordable and accessible.

How do we use solar panels today?

Today, they are an integral part of our lives, powering a multitude of appliances. From small devices such as calculators and watches to larger installations like homes, offices, and even entire solar PV farms, solar panels are transforming the way we consume energy.

Solar panels are widely used in residential solar panels installations, not only reducing energy bills by generating renewable power for household use but also allowing homeowners to send excess solar energy back to the grid, resulting in additional savings and an even lower energy bill.

In addition to solar panels, having a solar battery in your home can be beneficial, as many energy supplier offer attractive plans (eg. smart export guarantee) for battery owners, enabling you to store excess solar energy and further reduce your energy bills.

Harnessing the power of the sun with solar panels significantly on electricity bills and reduces energy bills by generating free, renewable electricity for your home or business. It also helps reduce our carbon footprint.

Like most technologies, solar panels have evolved over the years. There are several different types and technologies available on the market, each with its unique characteristics, efficiencies, and price points. These diverse options can make it difficult for consumers to choose which type is best suited for their needs.

What’s in this article?

In this article, we aim to demystify this technology. We will delve into the most popular types of solar panels currently on the market, examining their advantages and disadvantages.

We’ll also provide guidance on what to consider when deciding which solar panels technology is the best fit for your home. Whether you’re new to renewable solar energy or considering an upgrade, this article will provide the insights you need to make an informed decision.

Polycrystalline and Monocrystalline – what is the difference?

Monocrystalline and polycrystalline solar panels are two of the most common types of solar panels on the market, each with unique attributes that make them suitable for different applications.

Polycrystalline Solar Panels: These panels are made from multiple crystals and have a distinctive blue hue due to the light scattering off the different crystal formations. They are produced by pouring molten silicon into a cast, which is then cooled and cut into squares.

As a result, their manufacturing process is relatively simple and cost-effective. However, because of the multiple crystal structures in each cell, there is less space for electrons to move, which results in slightly lower efficiency compared to monocrystalline panels.

Monocrystalline Solar Panels: As the name suggests, these panels are made from a single, pure crystal structure, giving them a uniform dark black color. They are created through a more complex process known as the Czochralski method, where a silicon crystal ‘seed’ is placed in a vat of molten silicon and drawn out to form a solid crystal structure.

This process results in higher-purity silicon, which leads to higher efficiency rates. Monocrystalline panels also tend to have a longer lifespan and perform better in low-light conditions compared to polycrystalline panels.

While both types of panels have their merits, monocrystalline solar panels are becoming increasingly popular due to their higher efficiency and aesthetic appeal. The black color of monocrystalline panels is often preferred for residential installations for its sleek, uniform look.

Furthermore, as the technology and manufacturing processes for monocrystalline panels continue to improve, they are slowly displacing polycrystalline solar panels in the market.

What solar panels to choose from?

When choosing between polycrystalline and monocrystalline panels, it’s essential to consider your specific needs and circumstances. Factors such as your budget, space availability, aesthetic preference, and energy requirements all play a role in determining the best choice for your solar PV system installation.

N-type or P-type: What to choose?

P-type Solar Panels: P-type (Positive-type) solar PV cells are currently the most widely used in the photovoltaic industry. They are created by introducing an element, such as boron, that has fewer electrons than silicon into the silicon wafer.

This creates ‘holes,’ or positive charges, within the structure. P-type solar PV cells are popular due to their lower manufacturing costs and satisfactory performance under most conditions.

However, P-type cells are more susceptible to light-induced degradation (LID), where exposure to sunlight can cause a slight decrease in power output. They also have a higher susceptibility to high-temperature performance loss and can be slightly less efficient than n-type cells.

N-type Solar Panels: N-type (Negative-type) solar PV cells are made by introducing an element with more electrons than silicon, such as phosphorus, into the silicon wafer. This creates a negative charge within the cell. The key advantage of n-type cells is their higher efficiency: they can convert a larger percentage of sunlight into electricity, which means you get more power output for the same surface area.

N-type cells are also less susceptible to the effects of light-induced degradation and high-temperature performance loss, making them more durable and reliable in the long term. They have a higher initial cost than P-type cells, but the improved performance and lifespan can make them a better investment over time.

In recent years, n-type solar panels are becoming more popular and are poised to gain a larger market share. With their superior efficiency and durability, they are increasingly considered the better option, especially for high-demand applications or locations with space constraints.

N-Type and P-Type solar panels

As always, the choice between n-type and p-type solar panels will depend on your specific needs and circumstances, including budget, space, and energy requirements. But if efficiency and long-term performance are your main concerns, n-type panels would be a strong contender.

Is N-Type and P-Type solar panels the same as PERC and TOPCon?

N-type and p-type are not the same as PERC and TOPCon. N-type and p-type solar panels refer to the kind of doping (introduction of impurities into a semiconductor) that is done on the silicon wafers to create the photovoltaic (PV) effect.

On the other hand, PERC (Passivated Emitter and Rear Cell) and TOPCon (Tunnel Oxide Passivated Contact) solar panels are specific advanced cell technologies that can be applied to both n-type and p-type cells to enhance their efficiency.

PERC (Passivated Emitter and Rear Cell): PERC is an advanced solar cell technology that adds a passivation layer to the backside of a standard solar cell. This passivation layer allows for the reflection of light back into the cell for a second absorption chance, increasing the cell’s efficiency.

It also reduces the electron recombination, further improving power output. PERC cells are a significant development in solar technology, delivering higher efficiencies at a relatively low additional cost.

TOPCon (Tunnel Oxide Passivated Contact): TOPCon is another advanced solar panels cell technology, designed to reduce surface recombination and increase efficiency. TOPCon cells feature a passivation layer similar to PERC cells, but they also include an additional tunnel oxide layer and a doped polysilicon layer.

This structure minimizes electron recombination, maximizes the capture of light, and allows for better conductivity. TOPCon technology is often used in conjunction with n-type silicon cells, contributing to their high efficiency.

PERC vs. TOPCon

In conclusion, PERC and TOPCon are methods of enhancing the efficiency of solar cells, and they can be applied to both n-type and p-type cells. They represent advancements in solar technology that can help to maximize the power output of a solar panel.

Half-cut and Shiegled solar cells

Half-cut Cells: Also known as half-cell modules, this technology involves cutting a standard solar cell in half using a laser. The benefit is primarily in reducing the power loss caused by resistive heating, which occurs as electricity passes through the cell.

When you cut the cell in half, the current is also halved, so the power loss (which goes up with the square of the current) is cut to a quarter of what it was. This leads to an overall increase in efficiency for the panel. Additionally, half-cut cell modules are less affected by shading because each half operates independently.

Shingled Cells: Shingled cell modules use an innovative approach where solar cells are cut into thin strips and overlapped, similar to roof tiles and shingles. This increases the panel’s surface area exposed to sunlight and reduces unused space, boosting efficiency. Furthermore, shingling can reduce resistive losses since current paths are shorter, and the overlapping design allows the panel to better withstand thermal expansion and contraction.

When comparing the two, it’s important to note that both technologies aim to increase efficiency and power output. Half-cut cells have an advantage in shaded conditions due to their independent operation, and they reduce resistive losses significantly.

Shingled modules maximize the active area exposed to sunlight and can better handle temperature changes due to their unique design. The choice between the two often comes down to the specifics of the installation site and the performance needs of the solar system.

What about the look – how to get better-looking solar modules?

Standard Solar Modules: Standard solar modules typically consist of bluish or dark-colored solar cells with a grid-like metal pattern on the top, enclosed in a clear or white backsheet and an aluminum-colored metal frame. This traditional look is recognizable and common in many solar installations.

Full Black Solar Modules: Full black solar panels, on the other hand, use black solar cells, a black backsheet, and a black frame. This gives them a sleek, uniform appearance that many homeowners find more aesthetically pleasing. Full black solar panels work and are particularly popular for residential installations, especially on homes with dark-colored roofs, as they can blend in better with the roof aesthetics.

In terms of performance, the color of the solar cells, backsheet, or frame does not inherently impact the efficiency or power output of the panels. However, it’s worth noting that full black panels can potentially absorb more heat due to their dark color, which may cause a slight reduction in efficiency during peak sunlight hours, as solar panels tend to perform less efficiently at higher temperatures.

Despite this, the difference in real-world performance between full black and standard solar modules is typically negligible.

In conclusion, the choice between full black and standard solar modules mostly comes down to personal aesthetic preferences and the design considerations of your specific installation. If you’re seeking a sleek, uniform look for your solar installation, full black panels might be a suitable choice.

What is double-glass or Glass-Glass modules: are they worth the deal?

Double Glass Modules: As the name suggests, double glass solar panels, also known as glass-glass or dual-glass solar panels, are a type of solar module that encases the solar cells between two layers of tempered glass, instead of the traditional glass on front and plastic backsheet configuration.

What is the key advantage glass-glass solar panels?

The key advantage of double glass modules is their enhanced durability. Because glass is more robust and weather-resistant than the plastic used in backsheets, double glass modules can better withstand harsh environmental conditions such as heavy rain, snow, high humidity, and extreme temperatures. This makes them an excellent choice for installations in challenging climates or demanding applications such as large-scale commercial or utility projects.

Another advantage of double glass modules is their potential for bifacial solar cell implementation. Bifacial solar cells can capture sunlight from both sides, and when used in a double glass module, they can increase energy yield by up to 30% depending on installation conditions.

Standard Modules: Standard solar modules, on the other hand, use a single glass layer on the front to protect the solar cells and a plastic (often a polymer material like polyvinyl fluoride) backsheet on the rear. This design is lighter and less expensive than double glass modules, making it a popular choice for a wide range of applications.

However, plastic backsheets may degrade faster than glass, especially in harsh environmental conditions, potentially reducing the module’s lifespan. They are also not suitable for bifacial solar cell implementations, as the backsheet is opaque.

In conclusion, the choice between double glass and standard solar modules depends on your specific needs. Double glass modules can offer enhanced durability and the potential for higher energy yield (with bifacial cells), making them a good choice for challenging environments or large-scale projects. Standard modules, being lighter and less expensive, can be a more cost-effective option for less demanding applications.

Bifacial solar panels: how to use their potential?

Bifacial solar panels, as the name implies, are designed to generate electricity from both sides of the module. While the front side captures direct sunlight, the back side captures diffused and reflected light. Bifacial solar cells are typically sandwiched between two layers of glass, which allows sunlight to reach the back of the cells.

Compared to traditional (monofacial) panels, bifacial panels can significantly increase energy production – by up to 30%, depending on the conditions. The boost in production comes from the ability to capture additional light reflected off the surface underneath the panel.

How to fix bifacial solar panels?

However, to take full advantage of this, bifacial panels need to be installed in a way that maximizes exposure to reflected light. This makes them ideal for installations where there’s a highly reflective surface underneath, such as light-colored roofs, bodies of water, or snow-covered ground. They are also a great fit for ground-mounted systems, especially when mounted on a light-colored or reflective surface like white gravel or a specialized solar reflector.

In addition, bifacial panels are typically more durable because they are often made with double-glass construction. This makes them better suited to withstand harsh environmental conditions.

However, it’s worth noting that bifacial panels are typically more expensive than monofacial panels due to the increased complexity of the cells and the double-glass construction. Also, they may require specific racking systems to allow light to reach the back of the panels and to prevent them from casting a shadow on each other.

In summary, bifacial solar panels can be a great choice for specific situations where conditions allow for the capturing of reflected light. They provide increased energy production and are especially effective in large ground-mounted installations, installations with highly reflective surfaces, and in environments with plenty of light, like snowy areas or near bodies of water.

What about the power: how to reduce your energy bills?

Solar modules are typically classified according to their power output, which is measured in watts peak (Wp). This measure represents the maximum energy production under ideal sunlight conditions. Let’s explore three categories based on their power output: up to 400 Wp, 400-450 Wp, and above 450-500 Wp.

Solar panels up to 400 Wp

Solar panels in this category were widely used for many years, especially for residential installations due to their compact size and adequate performance. They were the standard for most installations and had the advantage of being more flexible for roofs with space constraints or complex designs.

However, as technology has advanced, panels with higher power outputs have become more prevalent and affordable. While panels up to 400 Wp are still being used and are more than sufficient for many installations, they are slowly being phased out in favor of higher power output panels.

Solar panels between 400-450 Wp

Solar panels in this power output range are increasingly becoming the preferred choice for residential and small commercial installations. They offer a good balance between size and energy production.

The higher power output means fewer panels are needed to reach the desired energy production level, which can save space, save money, reduce installation complexity, and potentially lower costs. Panels in this range are ideal for homeowners looking to maximize their solar investment and are a perfect fit for the average-sized rooftop.

Solar panels above 450-500 Wp

These high-power solar panels are typically used for large-scale commercial, industrial, and ground-mounted solar installations. They deliver excellent efficiency and the highest power output, allowing these large projects to maximize their energy production.

Despite their size and weight, which may pose installation challenges, these panels are the best option for maximizing space utilization in large areas. It’s worth noting, however, that due to their dimensions and weight, they may not be suitable for residential rooftops, and not every mounting system can accommodate these larger panels.

In conclusion, the choice of solar panel system power output depends largely on the installation process and the specific needs of the project. While higher power output panels can produce more energy and save space, they might come at a higher cost and may be more challenging to install. It’s always recommended to consider the specifics of the installation site and the energy needs of the project when selecting solar panels.

What are busbars: are they needed and how do they affect efficiency?

Busbars are thin wires or ribbons running through each solar cell that conduct the electrons – the electric current – generated when sunlight hits the cell. They play a critical role in the efficiency and performance of a solar panel.

The main function of busbars is to collect and carry the electric current from the cell to the panel’s junction box and then out to the external circuit. They also interconnect the cells within the module, forming an electrical network.

Traditionally, solar cells used to have around 2-3 busbars. However, as solar technology has advanced, the number of busbars has been increasing. Today, it’s not uncommon to find solar cells with 5, 6, 9, or even 12 busbars.

Increasing the number of busbars has several benefits:

1. Reduced Resistance: More busbars mean shorter paths for the electrons to travel, reducing electrical resistance, which can increase the cell’s efficiency.
2. Reduced Power Loss: Having more busbars can also reduce power loss due to cell breakage or micro-cracks because there are more paths for the electricity to flow.
3. Increased Durability: More busbars can provide additional structural support to the cells, making the panel more resistant to mechanical stresses and reducing the risk of cell breakage.

However, adding more busbars also comes with challenges. More busbars can create more shading on the cell, which can reduce the amount of sunlight hitting the cell and potentially offset the efficiency gains. Solar manufacturers have to balance the number of busbars and the shading they create to optimize the performance of the solar panels.

In conclusion, busbars are an essential component of solar panels that directly influence their efficiency and durability. Advancements in solar technology have led to an increase in the number of busbars per cell, which, when done right, can significantly enhance the performance of the solar panels.

What is IBC, i.e. the top achievement of technology at the moment?

IBC, or Interdigitated Back Contact, is a sophisticated solar cell technology where all the electrical contacts are located on the back side of the cell. Traditional solar cells have metal contacts or ‘busbars’ on the front side, which partially block sunlight from reaching the cell. By moving these contacts to the back, IBC cells can capture more sunlight and therefore produce more electricity.

The structure of IBC solar cells is more complex than that of standard cells. The front surface is purely dedicated to light absorption, while the back surface hosts both the n-type (negative) and p-type (positive) contacts, which are interdigitated, or interlocked like fingers. This unique design reduces electron travel distance, which minimizes energy loss and increases efficiency.

Furthermore, because the front side is free of metal contacts, IBC cells have a uniform, sleek appearance, which can be a desirable aesthetic feature for some homeowners.

However, the complex structure and manufacturing process of IBC cells make them more expensive than traditional solar cells. As such, they are often used in premium, high-efficiency solar panels.

Do busbars improve panel performance similarly to optimizers? Are optimizers needed then?

Busbars and power optimizers are both components that can improve the overall performance of a solar power system, but they operate in very different ways and at different stages of electricity generation.

Busbars

Busbars are physical components within each solar cell that help collect and transport the electrical current generated within the cell. They play a critical role in the initial conversion of sunlight into electricity. As explained earlier, increasing the number of busbars can enhance the performance of individual cells and thus, the entire solar panel.

Power optimizers

On the other hand, power optimizers are electronic devices connected at the solar module level that optimize the power output from each panel and mitigate any power loss due to shading or other factors. They work by constantly tracking the maximum power point of each module and adjusting the module’s voltage and current accordingly. This helps to maximize the power output of each module and, therefore, the entire array.

While busbars enhance the internal functioning of solar cells, power optimizers work to improve the performance and efficiency of the battery storage overall system after electricity generation.

Whether or not power optimizers are necessary when installing solar panels depends on your specific installation. In a system with no shading and all panels facing the same direction, power optimizers may not significantly improve the system’s performance.

However, in a system where panels are installed at different orientations, or where partial shading might occur, power optimizers can be beneficial in maximizing power output.

In summary, while both busbars and power optimizers improve the performance of a solar system, they do so in different ways and at different stages of the solar electricity production process. The decision to use power optimizers should be based on the specific conditions of your solar installation.

Summary

Today, we delved into the fascinating world of solar panel system technologies, discussing various types of solar cells and panels. This summary aims to clarify key distinctions and guide decisions about what solar panels to choose based on your specific needs.

Polycrystalline vs. Monocrystalline Solar Panels

Polycrystalline panels, identifiable by their bluish hue and square cells, were once more popular due to their lower cost. However, with technology advancements and cost reductions, monocrystalline panels, known for their high efficiency and sleek black appearance, have become a popular choice for both residential and commercial installations.

N-Type vs. P-Type Solar Cells

We examined n-type and p-type cells, highlighting that n-type cells, though slightly more expensive, offer superior efficiency and durability, making them a better long-term choice.

PERC and TOPCon Technology

PERC and TOPCon aren’t types of cells like n-type or p-type, but rather enhancements that can be applied to either n-type or p-type cells. These technologies boost efficiency by minimizing electron loss.

Half-Cut and Shingled Modules

We discussed how half-cut and shingled modules increase efficiency by reducing electrical resistance and increasing the surface area exposed to sunlight.

Full Black vs. Standard Solar Modules

Full black panels offer a sleek, aesthetically pleasing appearance, and blend seamlessly into darker rooftops, whereas standard modules are more cost-effective and widely used.

Double Glass and Bifacial Modules

Double glass modules, known for their durability, and bifacial modules, capable of harnessing sunlight from both sides, are perfect choices for specific installation environments.

Busbars and Power Optimizers

We discussed the role of busbars in solar cells and the potential benefits of power optimizers for enhancing solar system efficiency.