If you're looking to buy bifacial solar panels, you may have come across this increasingly popular solar technology and wondered how it differs from traditional solar panels. Bifacial modules are designed to generate electricity from both the front and rear of the panel, allowing them to make better use of available sunlight.
For the right installation, this can provide additional electricity generation and potentially improve the overall performance of a solar system.
What Are Bifacial Solar Panels?
Bifacial solar panels are photovoltaic modules designed to capture sunlight from both sides.
Traditional monofacial solar panels primarily generate electricity from sunlight hitting the front of the module. Bifacial panels can also capture useful light reaching the rear of the panel.
The rear side can make use of reflected and scattered sunlight from the surrounding environment, allowing additional light to reach the photovoltaic cells.
How Do Bifacial Solar Panels Work?
The basic photovoltaic process is similar to conventional solar panels.
When sunlight reaches the solar cells, the cells convert that light into electrical energy. With a bifacial module, this process can occur from both the front and rear surfaces.
The front typically receives direct sunlight, while the rear can capture light reflected from surfaces underneath and around the panel.
Potential sources of reflected light include:
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Light-coloured ground
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Concrete
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Gravel
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Reflective roofing
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Snow
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Other suitable surfaces
The amount of useful light reaching the rear will determine how much additional energy the bifacial panel can generate.
What Is Bifacial Gain?
The additional electricity produced by the rear side of a bifacial panel is known as bifacial gain.
Bifacial gain isn't a fixed percentage because it depends on the conditions of the installation.
Factors that can influence it include:
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Surface reflectivity
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Panel height
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Panel spacing
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Orientation
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Tilt angle
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Shading
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Local sunlight conditions
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Mounting configuration
This means a bifacial panel can perform differently depending on where and how it is installed.
Why Are Bifacial Panels Becoming More Popular?
The main attraction of bifacial technology is the potential to generate additional electricity without simply increasing the number of panels.
Instead of allowing reflected sunlight to go unused, bifacial modules can capture some of that light with their rear surface.
This can make them particularly attractive for larger solar installations where the mounting structure and surrounding environment can be designed to maximise rear-side exposure.
Where Are Bifacial Solar Panels Used?
Bifacial panels can be used in several different types of solar installation.
Ground-Mounted Solar
Ground-mounted systems can provide favourable conditions for bifacial panels because the modules can be elevated above the ground, giving reflected light an opportunity to reach the rear.
Commercial Solar
Commercial installations can benefit from bifacial technology where the mounting system provides sufficient rear-side exposure.
Solar Car Parks
Solar car parks use elevated structures, potentially allowing sunlight to reach both sides of the panels.
Residential Solar
Bifacial panels can also be installed on residential properties. However, the potential additional generation depends on factors such as the roof surface, panel elevation and mounting arrangement.
Bifacial vs Monofacial Solar Panels
The main difference between the two technologies is the number of surfaces capable of generating electricity.
Monofacial solar panels primarily generate electricity from the front.
Bifacial solar panels generate electricity from the front while also being capable of generating additional electricity from light reaching the rear.
However, bifacial panels don't automatically produce significantly more electricity in every situation. If there is very little useful light reaching the rear, the additional generation may be limited.
What Should You Consider Before Buying?
If you're planning to buy bifacial solar panels, don't focus solely on the panel's wattage.
Important specifications to compare include:
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Power output
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Module efficiency
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Bifaciality factor
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Panel dimensions
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Product warranty
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Performance warranty
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Degradation rate
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Temperature coefficient
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Mounting requirements
It's also important to make sure the panels are compatible with your chosen inverter and mounting system.
Does Installation Affect Performance?
Yes. Installation design can have a major impact on bifacial performance.
A panel mounted very close to a dark surface may receive little useful reflected light from behind. An elevated panel installed above a more reflective surface can provide much better conditions for rear-side generation.
Panel spacing and shading should also be considered when designing the system.
Are Bifacial Solar Panels Right for You?
Bifacial panels can be a strong option for installations where the rear of the modules has good access to useful light.
However, they aren't necessarily the best choice for every project. The installation conditions, expected energy generation and total system cost should all be considered before making a purchase.
A professional solar assessment can help determine whether bifacial technology is suitable for your property or project.
Conclusion
Bifacial solar panels provide a modern approach to solar generation by allowing photovoltaic cells to capture sunlight from both the front and rear of the module.
When installed in suitable conditions, they can potentially produce additional electricity and make better use of available sunlight.
If you're looking to buy bifacial solar panels, understanding how the technology works is the first step towards choosing the right equipment for your system.
In the next article in this series, we'll explore how much energy bifacial solar panels can generate and the factors that have the biggest impact on their performance.
