Bifacial solar panels: how they boost energy output

The global transition towards cleaner and more sustainable energy sources is well underway, and the United Kingdom is increasingly investing in renewable energy solutions. Among the most promising technologies in the solar energy sector, bifacial solar panels stand out due to their ability to generate electricity from both the front and rear surfaces. This unique capability allows them to produce more energy per square metre, without increasing the physical footprint of the installation.

Bifacial solar panels represent an evolution in photovoltaic design. By harnessing both direct sunlight and reflected light from the surrounding environment, they outperform traditional solar modules under the right conditions. As this technology becomes more widespread, it is poised to play a key role in improving the efficiency and effectiveness of solar power systems across the UK and beyond.

What Are Bifacial Solar Panels?

Bifacial solar panels are photovoltaic modules designed to absorb sunlight from both sides — the front and the rear. Unlike traditional solar panels, which typically have an opaque backsheet, bifacial panels use transparent materials such as tempered glass on both sides. This enables light to reach the solar cells from multiple directions, boosting energy production.

The rear side of the panel captures ambient light and sunlight that reflects off surfaces such as rooftops, pavements, or the ground. Although the front face contributes the majority of the energy, the rear side can add a significant percentage to the overall output, especially when installed above highly reflective surfaces like white membranes, concrete, snow, or sand.

How Bifacial Solar Panels Work

The operating principle behind bifacial solar panels is the same as that of any photovoltaic system: solar cells convert sunlight into electricity via the photovoltaic effect. What sets bifacial panels apart is their dual-sided exposure to light, allowing them to harness more energy without additional space.

Typically, bifacial panels are installed on raised mounting structures that permit light to reach the underside of the module. The more reflective the surface beneath the panels, the greater the benefit. This additional captured light, known as albedo, increases energy generation from the rear, particularly in installations where reflective surfaces are planned or naturally present.

Bifacial panels also perform better in diffuse light conditions, such as on overcast days — which are frequent in the UK. By absorbing light from multiple angles, they help maintain steady output even when direct sunlight is limited.

Key Advantages of Bifacial Solar Panels

One of the primary advantages of bifacial solar panels is their ability to produce more electricity compared to conventional monofacial modules. Under optimal conditions, they can deliver 10% to 30% more energy, thanks to the contribution of rear-side light capture.

These panels are also more durable. Made with tempered glass on both sides, they resist harsh weather, mechanical stress, and degradation more effectively than traditional panels. This robust construction can lead to longer service life and reduced maintenance over time.

Another advantage is their versatility. Bifacial panels are suitable for a wide range of applications — from commercial rooftops and ground-mounted systems to solar carports and architectural integrations like canopies and façades. Their semi-transparent appearance also offers aesthetic benefits for installations where visual design matters.

Comparing Bifacial and Traditional Panels

Compared to traditional solar panels, bifacial solar panels offer greater energy efficiency due to their dual-surface functionality. While conventional panels rely solely on direct sunlight hitting the front face, bifacial modules benefit from additional reflected light captured by the rear, resulting in a notable increase in energy yield.

In terms of thermal performance, bifacial panels often operate at lower temperatures due to their design, which allows better air circulation and natural cooling. This feature can be particularly beneficial during warmer months, helping to mitigate efficiency losses caused by overheating.

Although the upfront cost of bifacial panels may be higher due to more complex materials and mounting systems, the long-term benefits often outweigh the initial investment. When measuring energy cost over the system’s lifespan — known as the levelised cost of electricity (LCOE) — bifacial panels frequently emerge as the more economical choice.

Optimal Installation Conditions

To maximise the performance of bifacial solar panels, specific installation conditions must be met. The most critical factor is ground reflectivity (albedo). Surfaces such as white gravel, light concrete, metal rooftops, or specially designed reflective coatings enhance the amount of light reaching the rear face.

Another crucial aspect is elevation. Raising the panels above ground level allows more reflected light to reach the rear surface while improving airflow around the panels. This configuration reduces shading and contributes to more consistent output.

Orientation and tilt angle also influence performance. Although bifacial modules work well in both fixed and tracking systems, they are particularly effective when paired with solar trackers that follow the sun’s path throughout the day. These systems optimise light capture from both faces and enhance energy production throughout different seasons.

Applications in the UK Context

In the UK, bifacial solar panels are gaining attention as part of a broader shift towards more efficient renewable energy systems. Although the country experiences less direct sunlight than some other regions, bifacial technology offers distinct advantages in environments where diffuse and reflected light are prevalent.

Urban installations — such as on white or light-coloured flat rooftops — can particularly benefit from bifacial panels, as can solar canopies in public spaces and carports in business parks. These settings often feature surfaces that naturally reflect light, making them ideal candidates for bifacial systems.

There is also growing interest in using bifacial panels in agricultural contexts. So-called agrivoltaic systems involve installing solar panels above crops or livestock areas. The see-through design of bifacial panels allows light to filter down while generating power, creating a synergy between food and energy production — an increasingly important approach for sustainable development.

Economic Impact and ROI

From a financial perspective, bifacial solar panels can initially be more expensive due to material costs and installation complexities. However, the enhanced energy output means that they often offer a better return on investment (ROI) over time.

When installed in favourable conditions, such as high-reflectivity environments with good solar exposure, bifacial systems can recover their initial cost in as little as five to seven years. Over the lifetime of the panels — typically 25 to 30 years — this results in significant cost savings compared to traditional systems.

In the UK, government schemes such as the Smart Export Guarantee (SEG) and regional grants for renewable installations help make solar power more accessible. These programmes can further improve the financial viability of bifacial systems by offering payment for excess electricity fed into the grid or supporting initial capital costs.

Recent Technological Developments

Recent years have seen rapid advancements in bifacial solar panel technology. Manufacturers have refined solar cell designs to increase rear-side efficiency, enhanced anti-reflective coatings, and developed lightweight yet durable glass compositions.

New generation solar tracking systems have also become more sophisticated, integrating with bifacial panel setups to optimise sun exposure on both sides. These trackers adjust the panel orientation throughout the day, significantly improving energy harvest compared to static mounts.

Additionally, monitoring technologies have improved. Today’s bifacial systems can be equipped with sensors and smart analytics tools that track the performance of each panel face. This data enables better maintenance, faster fault detection, and long-term optimisation of system output.

Future Prospects for Bifacial Panels

Looking ahead, bifacial solar panels are expected to become a central feature in the global solar market. Their ability to generate more energy without increasing land use or installation footprint makes them an ideal choice for densely populated or space-constrained areas.

As more solar developers seek to maximise system efficiency and reduce environmental impact, bifacial technology is likely to become the default option for new installations. Falling production costs, combined with mounting expertise and favourable policy frameworks, will further drive adoption across residential, commercial, and utility sectors.

In the UK, where renewable energy is playing a growing role in energy policy and infrastructure planning, bifacial panels offer a practical way to enhance solar productivity, especially in challenging weather conditions. As a result, they are set to be a key contributor to the country’s low-carbon future.

Frequently Asked Questions (FAQ)

What is the main difference between bifacial and traditional solar panels?
Bifacial panels capture light from both the front and rear sides, whereas traditional panels only absorb light from the front-facing surface.

Are bifacial solar panels suitable for homes?
Yes. They can be used in domestic settings, particularly on rooftops or pergolas where rear-side light can be reflected effectively.

Do bifacial panels need reflective surfaces underneath?
While not essential, reflective surfaces such as gravel, concrete, or metal increase rear-side efficiency and improve energy yield.

Are they more difficult to install?
Installation requires attention to mounting height and potential shading, but professional installers can easily adapt to these requirements.

How much more power do they generate?
Depending on installation conditions, bifacial panels can produce 10% to 30% more energy than monofacial panels, making them highly efficient.