Bifacial Solar Panels
As their name suggests, bifacial solar panels are solar panels that absorb light from both sides. This means that at the right angle, the top of a panel could absorb light like normal while the bottom could absorb light reflected from other nearby surfaces increasing the power output of the panel.
When bifacial modules are installed on a highly reflective surface (like a white thermoplastic polyolefin (TPO) 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 modules come in many designs. Some are framed while others are frameless. Some are dual-glass, and others use clear back sheets. Most use monocrystalline cells, but there are polycrystalline designs. The one thing that is constant is that power is produced from both sides. There are frameless, dual-glass modules that expose the backside of cells but are not bifacial. True bifacial modules have contacts/busbars on both the front and back sides of their cells.
How are bifacial modules installed?
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 overtightening bolts and damaging the glass.
The higher a bifacial module is installed, 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. Junction boxes on bifacial panels have become smaller or separated into multiple units positioned along the panel’s edge to prevent shading. Mounting and racking systems specially formatted for bifacial installations take out the question of backside shading.