Solar technology has come a long way since French physicist Edmond Becquerel discovered the photovoltaic effect in 1839. Today, innovative bifacial solar panels are helping homeowners and businesses generate more electricity from sunlight.
Unlike traditional solar panels that capture sunlight from one side, bifacial solar panels generate electricity from both the front and back. They use direct sunlight along with light reflected from the ground and surrounding surfaces, potentially producing 5% to 20% more electricity under suitable conditions.
But that extra energy doesn’t come automatically. Factors such as surface reflectivity, mounting height, and panel placement can affect performance. Before investing, it’s worth understanding how bifacial solar panels work, what influences their energy gains, and how to choose the right panels for your property.
Are Bifacial Solar Panels Better Than Monofacial Panels?
Bifacial solar panels can generate approximately 5% to 20% more electricity than conventional monofacial models, with even higher gains possible under favourable conditions. Although they may require a greater upfront investment, their additional energy output can make them a cost-effective choice over the long term.
Their advantage comes from the ability to capture more than direct sunlight. In addition to the light reaching the front surface, bifacial panels collect sunlight reflected from the ground and surrounding surfaces, as well as scattered light reaching the rear.
This makes albedo, a measure of how much sunlight a surface reflects, particularly important. The more reflective the surroundings, the greater the potential contribution from the rear side of the panel.
Construction is another key difference. While conventional panels typically feature an opaque backsheet that prevents light from entering through the rear, bifacial models use transparent backsheets or dual-glass construction. The latter can also improve durability and provide additional protection against environmental exposure.
Installation is generally more demanding, but bifacial panels offer greater flexibility in how they can be positioned. Besides traditional tilted arrangements, they can be installed vertically, allowing them to capture sunlight at different times of day.
Vertical configurations can be particularly useful in locations where morning and evening electricity generation is a priority. With appropriately engineered mounting systems, they can also withstand challenging weather conditions, including strong winds.
What Affects the Additional Energy Gain?
Although bifacial panels can generate considerably more electricity than monofacial alternatives, choosing this technology doesn’t automatically guarantee a 20% increase in output.
Actual performance depends on several factors, including the surrounding surfaces, mounting height, panel spacing and orientation. Understanding these conditions before installation is essential for getting the most from your investment.
Surface Reflectivity
The surface beneath and around the panels plays a major role in determining how much additional energy they can generate.
Dark materials, such as asphalt and dark soil, absorb more sunlight and reflect less towards the rear of the panels. Light-coloured surfaces, including concrete and pale gravel, generally offer better conditions for bifacial energy generation.
Shading is equally important. Trees, nearby buildings and other obstructions can reduce the sunlight reaching either side of the panel, limiting potential gains.
For this reason, elevated ground-mounted systems and solar carports are often particularly suitable for bifacial technology. They provide more opportunities for reflected light to reach the rear surface than a typical flush-mounted residential rooftop installation.
Panel Height
Mounting height influences how much reflected light can reach the underside of a bifacial panel.
Panels positioned too close to the ground may receive less rear-side illumination, reducing the additional electricity they can generate. Raising them creates more space for reflected and scattered light to reach the rear cells.
Depending on the installation, ground-mounted systems may use clearances of around 1 to 2 metres, while some elevated flat-roof arrangements may require approximately 1.8 to 3 metres.
However, these figures are not universal requirements. The ideal height depends on panel dimensions, mounting design, surrounding surfaces, structural limitations and project economics. Greater elevation can improve rear-side exposure, but it can also increase installation costs.
Panel Spacing
Spacing is another important consideration, particularly when installing multiple rows of bifacial panels.
If the rows are positioned too closely together, neighbouring panels may cast shadows and restrict the amount of reflected sunlight reaching the rear surfaces.
Depending on the system design, inter-row spacing of approximately 2.5 metres may be considered, while larger installations with sufficient available land may benefit from wider spacing, potentially up to 6 metres.
The optimal distance depends on panel tilt, height, latitude and available space. Wider spacing can improve light exposure, but it also reduces the number of panels that can fit within a given area. Finding the right balance is therefore essential.
Panel Direction and Tilt
The orientation of bifacial panels affects both direct sunlight exposure and the amount of energy collected from the rear.
In the UK, south-facing panels installed at a tilt of approximately 30 to 40 degrees are often a practical starting point for maximising annual solar exposure.
However, this isn’t the only effective configuration.
Vertical, east-west-facing bifacial panels can capture more sunlight during the morning and evening, potentially producing electricity at times when demand is higher.
The best arrangement depends on the property’s location, surrounding environment, available installation space and intended energy-use patterns. Panel height, spacing and surface reflectivity should all be considered alongside orientation.
What to Consider When Buying Bifacial Solar Panels
With a growing selection of bifacial solar panels available in different sizes, designs and technologies, choosing the right model involves more than comparing advertised wattage.
Cell technology, technical specifications, construction and total installation costs can all influence long-term performance and value.
Cell Technology
The type of solar cell used in a bifacial panel affects its efficiency, rear-side performance and overall cost.
PERC (Passivated Emitter and Rear Contact) technology has been widely adopted thanks to its established reliability and relatively affordable production costs.
However, newer options such as N-type TOPCon (Tunnel Oxide Passivated Contact) and HJT (Heterojunction) technology can offer improved efficiency and higher bifaciality.
A higher bifaciality factor means the rear side can produce a greater proportion of the power generated by the front under comparable conditions.
While advanced cell technologies may cost more initially, their improved performance can make them attractive for installations where maximising electricity generation is a priority.
Technical Specifications
When comparing bifacial solar panels, look beyond the headline power rating. Several specifications can make a significant difference to real-world performance:
- Bifaciality factor: Indicates the rear side’s power output relative to the front under comparable conditions. Higher values suggest greater potential to benefit from rear-side illumination.
- Testing conditions: Check whether advertised output figures refer only to front-side performance or include additional rear-side gains under specified conditions.
- Wattage: Consider the panel’s rated power alongside its potential additional output from reflected sunlight.
- Temperature coefficient: Shows how performance changes as the panel temperature rises. A lower temperature-related power loss is generally preferable.
Weight and structural compatibility are also important, particularly with dual-glass models, which can be heavier than conventional alternatives.
Before purchasing, make sure the panels are compatible with the intended mounting structure and can be safely supported without unnecessary modifications.
It’s also worth checking product and performance warranties, along with relevant safety and quality certifications. These provide reassurance about durability, long-term output and compliance with installation standards.
Total Investment and Installation Costs
The purchase price is only one part of the overall investment in bifacial solar technology. Because these panels often perform best when elevated and properly spaced, installation may require specialised mounting systems, additional structural support and more detailed planning.
Dual-glass panels can also add weight, potentially increasing the cost of racking and reinforcement. Other expenses may involve preparing reflective ground surfaces, determining the optimal row spacing and calculating the correct clearance for rear-side light exposure.
Professional design and installation are especially important for more complex systems, including elevated ground-mounted arrays, commercial rooftops and solar carports.
While these requirements can increase upfront costs, they should be weighed against the additional electricity the system is expected to generate throughout its operating life.
Ultimately, the value of bifacial solar panels comes down to more than their ability to capture sunlight from two directions. Their performance depends on choosing the right technology, installing it in suitable conditions and balancing the additional energy yield against the total cost.
Are Bifacial Solar Panels Worth It?
In short, the main advantages of bifacial solar panels are their higher potential output, their flexibility to be mounted vertically or in elevated systems, and the added durability of dual-glass construction. The main drawbacks are the higher upfront and installation costs, the extra weight of dual-glass panels, and smaller gains on flush-mounted rooftops.
Bifacial solar panels can be a smart investment when the installation allows both sides to capture enough sunlight. They work particularly well in elevated ground-mounted systems, solar carports, and other locations with reflective surfaces and minimal shading.
For homeowners with limited roof space or panels mounted close to the roof, the additional energy gains may be smaller. Higher installation costs can also offset some of the long-term savings.
Before choosing bifacial panels, compare their expected energy output, installation requirements, and total cost with those of conventional solar panels. A professional solar installer can help assess your property and determine whether the extra electricity generation justifies the investment.
