Bifacial solar modules

""Australian National University researchers claim to have set a world record for bifacial solar cell efficiency that they say could boost the energy output of solar farms by 30%.""

 Bifacial modules produce solar power from both sides of the panel. Whereas traditional opaque-back sheeted panels are mono facial, bifacial modules expose both the front and backside of the solar cells. When bifacial modules are installed on a highly reflective surface (like a white TPO roof or on the ground with light-colored stones), some bifacial module manufacturers claim up to a 30% increase in production just from the extra power generated from the rear.

Bifacial solar panels perform best when they’re mounted near reflective surfaces, such as swimming pools, glass, or areas where the ground is reflective. That way the solar panel can capture energy from above and below. Sandy and snowy areas are high-performing environments for bifacial solar panels. They also do well when mounted on pergolas and open walkways, and can be a great aesthetic choice to help create a shady overhang.

Installation of bi facial modules

The way a bifacial module is mounted depends on its type. A framed bifacial module might be easier to install than frameless, just because traditional mounting and racking systems are already adapted to framed models. Most bifacial module manufacturers provide their own clamps to mount their specific brand, taking away any installation hesitations.

For frameless bifacial modules, the module clamps will often feature rubber guards to protect the glass, and special care must be taken to prevent over tightening bolts and damaging the glass.

The higher a bifacial module is tilted, the more power it produces from its bifacial properties. Bifacial modules mounted flush to a rooftop block any reflected light from reaching the backside of the cells. That’s why bifacial modules perform better on flat commercial rooftops and ground-mounted arrays, because there is more room for tilt and bouncing reflected light to the rear of the modules.

The mounting system itself can affect the performance of the bifacial modules. Racking systems with support rails usually covered by a mono 

facial module’s back sheet will shade back rows of bifacial cells. Junction boxes on bifacial panels have become smaller or separated into multiple units positioned along the panel’s edge to prevent shading, too. Mounting and racking systems specially formatted for bifacial installations take out the question of backside shading.

How do they work?a

Bi facial solar panels work just like normal solar panels. They use the same semiconductor material which generates power by converting light energy into electricity. When sunlight hits the bifacial panel, a portion of the sun’s light is absorbed by the solar cells and converted into electrical energy. Some of the light is caught in the glass and is reflected throughout the interior of the panel until it strikes a solar cell and gets absorbed. Some of the light passes right through the glass panel and strikes the ground. Assuming the ground has a high reflectance, this light then bounces back toward the panel and is converted into electricity.

Since they are made to capture energy on both sides, they are constructed differently. They don’t have the metal grid lines that are seen on a normal panel. Instead, the solar cells are held in place by the glass structure. They also don’t require a metal frame. The tempered glass helps make them more durable and weather resistant and the lack of a frame reduces corrosion and efficiency losses due to potential induced degradation, also called PID.

Solar cells in bifacial solar panels are exactly the same as in mono facial solar panels. The only real difference is that the solar cells are made to be two-sided, so the silicon p & n layers are exposed on the backside. Depending on the configuration, extra conductors may be added to the backside of the panel.