Bifacial Solar Panels: What Are They & How Do They Work?

When it comes down to installing solar panels, the goal is always to design your system to generate as much solar energy as possible. The technology used in solar panels has come a long way. One particularly exciting technology development, is bifacial solar panels. Despite bifacial modules being around since the 1960’s, through the development of PERC (passivated emitter rear cell) technology they have since become a disruptor in the solar PV market. So what are bifacial solar panels and why are they worth considering? Read on to find out!

What are Bifacial Solar Panels?

Solar PV panels are made up of one of two different types of crystalline cells; monocrystalline or polycrystalline cells. The majority of bifacial solar panels are made from monocrystalline cells. As monocrystalline cells are more efficient, despite being more expensive. Solar cells in bifacial solar panels are exactly the same as in monofacial solar panels. The only real difference is how the panel is made. Whereas traditional monofacial solar panels have an opaque backsheet, Bifacial solar panels have a reflective back or dual panes of glass holding the solar cells in place. Exposing the solar cells to sunlight at the back as-well as the front. As a result, bifacial solar panels have a higher efficiency, as they are capable of capturing sunlight on both sides. Since they’re made to be completely transparent, they are usually frameless without metal gridlines. This makes them stronger in structural integrity and easier on the eye.

So what is a Monofacial Solar Panel?

The majority of solar panels that we install across the UK are monofacial panels. A monofacial module, unlike a bifacial module, can only generate energy from the front of the solar panels.

How do Bifacial Solar Panels Work?

Bifacial solar panels work just like normal solar panels. There is a potion of sunlight that is directly absorbed by the solar cells and converted into electricity. Along with a portion of sunlight that is trapped inside the glass that bounces around until it is absorbed by a solar cell. And finally there is a portion of light which passes right through. However this is where bifacial panels and monofacial panels are different. In a bifacial panel this loss light then has a chance to be reabsorbed by the panel. In this instance, where the light passes right through and collides with a highly reflective surface, this then bounces back towards the panels, to be converted into solar energy. As a result of exposing both sides of the solar cells to sunlight, bifacial solar panels are capable of generating more solar energy.

How much more energy can bifacial solar panels generate?

Bifacial solar panels perform best when installed near highly reflective surfaces. Such as swimming pools glass, sandy, stoney or snowy areas. Although the front of the panel still absorbs the majority of the sunlight, some bifacial models are capable of increasing energy production by up to 30%. The exact amount of extra energy will depend on the environment surrounding the solar panels themselves.

Pros & Cons of Bifacial Solar Panels

Bifacial solar panels are becoming increasingly popular, gaining attention due to both their affordability and efficiency. More homes and businesses are choosing to install bifacial over monofacial panels to reap the rewards, but do the advantages truly outweigh the disadvantages?

The Advantages of Bifacial Solar Panels

Increased Efficiency. As bifacial modules can produce powers from both sides of the panel, there is an overall increase in energy generation. Some manufacturers claim that bifacial solar panels can generate up to 30% more energy than conventional monofacial solar panels. This higher efficiency translates into less space per watt, so homeowners can install fewer panels to meet their needs.
More Durable. As bifacial panels are frameless, and are covered both sides by tempered glass, they're often more durable. The tempered glass is weather-resistant, UV resistant and can withstand high temperatures and strong winds. As a result of their durability, bifacial solar panels are expected to have longer lifespans.
Aesthetically Pleasing. Bifacial modules come in many designs, including frameless. Many see the complete glass frame more aesthetically pleasing compared to monofacial solar panels.
Works Well in Diffuse Light. The extra surface area also means that bifacial panels perform better in diffuse light. Making the long-term costs lower than monofacial panels.
Reduced PID. In the instance of a frameless bifacial panel, the solar cells are less likely to suffer from potential-induced degradation (PID). This is where electrical currents stray from their intended path and as a result corrodes the solar panels. Furthermore, bifacial panels without a metal frame don’t require grounding, as there are no metal contacts on the exterior.
Longer Warranties. Bifacial solar panels often come with a longer warranty of up to 30 years.

The Disadvantages of Bifacial Solar Panels

Can you use bifiacial panels on a roof?

Bifacial solar panels work best when they lie around four metres from the ground. This is because the higher up the panel sits, the more light is able to get underneath them. For this reason bifacial solar panels are unlikely to suit a residential setting, but work well in solar farms, off-grid systems, or commercially.

BIFACIAL SOLAR PANEL MANUFACTURERS

There are a small handful of manufacturers that currently have bifacial solar panels in the UK market. Current Bifacial manufacturers include: LG, Canadian Solar, Longi, Trina Solar, and Yingli Solar. However, with increasing popularity we expect this to rise as bifacial modules become more mainstream.