When choosing solar panels for a UK property or commercial installation, one of the biggest decisions is whether to use traditional monofacial panels or newer bifacial solar panels.
Both technologies can provide reliable renewable electricity, but they work differently. Bifacial modules are designed to generate electricity from both the front and rear of the panel, while traditional monofacial panels primarily use the front surface.
So, which is better for the UK?
The answer depends on the type of installation, available space, mounting system and how much useful light can reach the rear of the panels.
What Are Traditional Solar Panels?
Traditional solar panels are generally known as monofacial solar panels.
They are designed to generate electricity primarily from sunlight reaching the front of the module. The rear of the panel is mainly there to provide protection and structural support.
They have been used extensively across UK homes, businesses and large solar projects and remain a popular choice because they are relatively straightforward to install and work effectively in a wide range of conditions.
What Are Bifacial Solar Panels?
Bifacial solar panels are designed to generate electricity from both sides.
The front captures direct sunlight, while the rear can capture reflected and scattered light from the surrounding environment.
For example, sunlight can hit a light-coloured surface underneath an elevated panel and reflect towards the rear of the module.
The additional electricity produced from the rear is commonly referred to as bifacial gain.
Bifacial vs Traditional Solar Panels
| Feature | Bifacial Solar Panels | Traditional Solar Panels |
|---|---|---|
| Front-side generation | Yes | Yes |
| Rear-side generation | Yes | Generally no |
| Potential additional generation | Yes | Limited |
| Benefit from reflective surfaces | High | Low |
| Installation complexity | Can be higher | Generally simpler |
| Ground-mounted suitability | Excellent | Excellent |
| Residential rooftop suitability | Depends on installation | Generally excellent |
| Potential lifetime energy yield | Higher in suitable conditions | Standard |
The main difference is therefore the ability of bifacial panels to make use of light reaching the rear.
Which Produces More Electricity?
In suitable conditions, bifacial solar panels can produce more electricity than comparable monofacial panels.
However, this doesn't mean that every bifacial installation will automatically generate significantly more energy.
The rear of the panel needs access to useful light.
Factors such as:
- Surface reflectivity
- Panel height
- Panel spacing
- Tilt
- Orientation
- Shading
- Mounting design
can all affect the additional energy generated.
A bifacial panel mounted very close to a dark roof may have little opportunity to benefit from its rear surface.
How Does the UK Climate Affect the Comparison?
The UK has a mixture of direct and diffuse sunlight throughout the year.
While the UK receives less solar irradiation than many southern European countries, solar panels can still produce substantial amounts of electricity.
Bifacial modules can also make use of diffuse light when conditions allow.
However, the UK's frequently cloudy conditions mean that system design remains important. The rear of the panel needs to receive enough useful light for bifacial technology to provide a meaningful advantage.
The Importance of Surface Reflectivity
Surface reflectivity is one of the biggest differences between a well-designed bifacial installation and a standard installation.
A light-coloured or reflective surface can send additional light towards the rear of the panel.
A darker surface will generally absorb more light.
This can make a significant difference in certain applications.
For example, an elevated bifacial system above a suitable reflective surface could have greater rear-side generation potential than the same panel installed directly above a dark surface.
Bifacial Solar Panels for UK Homes
For many UK homeowners, traditional monofacial panels remain a practical option.
Residential panels are often installed relatively close to the roof. This can restrict the amount of sunlight reaching the rear of a bifacial panel.
If there is very little rear-side light available, paying more for bifacial technology may not provide a worthwhile return.
However, bifacial panels can still make sense for certain residential installations where there is suitable clearance and favourable surface conditions.
The key is to assess the actual roof and mounting arrangement rather than assuming one technology is always better.
Bifacial Solar Panels for UK Businesses
Commercial and industrial properties can provide better opportunities for bifacial technology.
Large rooftops, ground-mounted systems and solar carports can all potentially provide the space and clearance required for rear-side generation.
For a business with significant electricity consumption, additional solar generation can potentially reduce the amount of electricity purchased from the grid.
When the system is large, even a relatively small increase in energy generation can become significant over its lifetime.
Ground-Mounted Solar
Ground-mounted solar is one of the strongest applications for bifacial panels.
The modules can be elevated above the ground, allowing light to reach the rear.
The ground surface can also reflect sunlight upwards.
When designing a UK ground-mounted system, factors such as ground conditions, vegetation, row spacing, panel height and orientation should all be considered.
Traditional monofacial panels can still perform very well in ground-mounted systems, but bifacial technology provides another opportunity to increase energy yield.
Solar Carports
Solar carports can also be particularly suitable for bifacial panels.
Because the modules are raised above parking spaces, there is naturally an open area underneath them.
This allows light to reach the rear while the surface below can provide additional reflected light.
For UK businesses, shopping centres, workplaces and car parks, bifacial solar carports can therefore be an interesting option.
Installation Considerations
Traditional panels are generally simpler to install because the rear doesn't need to receive sunlight.
With bifacial solar panels, the mounting structure becomes more important.
Installers need to consider:
- Clearance beneath the panels
- Mounting components
- Cable positioning
- Panel spacing
- Surface reflectivity
- Potential shading
The objective is to minimise unnecessary obstruction behind the module.
Cost Comparison
Another important consideration is price.
Depending on the manufacturer, bifacial panels can have a higher upfront cost than some traditional panels.
The mounting system may also need to be designed differently to take advantage of rear-side generation.
However, the cheapest panel isn't necessarily the cheapest system over its lifetime.
A better comparison looks at:
Total installation cost → expected energy generation → long-term savings → return on investment.
If bifacial panels generate substantially more electricity under the specific site conditions, the additional cost could potentially be justified.
Durability
Many modern bifacial panels use glass-glass construction.
This can provide strong protection for the solar cells and make them suitable for long-term applications.
However, construction and specifications vary between manufacturers.
When comparing bifacial and traditional panels, it is worth looking at:
- Product warranty
- Performance warranty
- Module efficiency
- Temperature coefficient
- Mechanical load rating
- Degradation rate
- Manufacturer reputation
When Are Bifacial Solar Panels Better?
Bifacial panels can be particularly attractive when:
- The rear receives plenty of useful light.
- The panels can be elevated.
- The surface underneath is reflective.
- There is sufficient space between rows.
- The project prioritises maximum energy generation.
- The additional cost can be justified.
These conditions are more commonly found in ground-mounted, commercial and solar-carport installations.
When Are Traditional Panels Better?
Traditional monofacial panels may be the better option when:
- Panels are mounted close to a dark roof.
- Very little light reaches the rear.
- The installation needs to be as simple as possible.
- The additional cost of bifacial technology isn't justified.
- Available space makes a conventional layout more practical.
For many standard UK residential rooftops, monofacial panels can therefore remain an excellent choice.
So, Which Is Better?
There is no universal winner.
Bifacial solar panels are potentially better when the installation is specifically designed to take advantage of rear-side generation.
Traditional solar panels can be better when the rear of the module receives little useful light or when keeping the system simple and cost-effective is the priority.
The best technology should be selected based on the specific site rather than simply choosing the newer option.
Final Thoughts
The choice between bifacial solar panels UK installations and traditional monofacial panels ultimately comes down to the conditions of the project.
Bifacial technology can provide additional energy generation where the rear of the modules has good access to sunlight and reflected light. This makes it particularly interesting for ground-mounted systems, solar carports and some commercial installations.
For many conventional UK rooftops, however, traditional monofacial panels may still provide excellent performance and value.
In the next article in this series, we'll examine how much energy bifacial solar panels can generate in the UK and the factors that determine their real-world bifacial gain.
