Solar PV technology trends: Moving towards the Bifacial modules
Bifacial PV modules have gained increasing attention in recent years due to their higher power output and potential for cost savings. Bifacial modules are designed to capture sunlight from both sides, resulting in higher energy production compared to traditional modules. This blog article will explore the drivers and benefits of bifacial PV modules, as well as the potential risks associated with their use.
Drivers & Benefits Bifacial modules are enabled by new(er) cell technologies, such as passivated emitter and rear cell (PERC) and heterojunction technology (HJT). These new cell technologies allow for higher power output and improved efficiency, which translates into a lower levelized cost of electricity (LCOE) and a higher return on investment (ROI) for the end user.
In addition, bifacial modules can take advantage of reflected sunlight from the ground or other surfaces, further increasing their power output. As the cost gap between mono- and bifacial modules decreases, bifacial modules are becoming a more attractive option for solar projects of all sizes.
Potential Risks One potential risk associated with bifacial modules is their increased weight due to their glass-glass construction with large format modules, which can lead to a higher risk of damage during shipping, handling, and installation. Corrosion is also a concern, as acetic acid can form from the ethylene-vinyl acetate (EVA) encapsulant used in the modules.
Another potential risk is cell fracture, as the benefits of putting cells into the neutral axis might be offset by residual stresses introduced during lamination. Thinner glass front sheets can also make cells more prone to cracking during hail events.
Rear-side potential induced degradation (PID) is another concern, which is degradation due to depolarization of the passivation layers (PID-p) or corrosion of the silicon (PID-c) below the passivating layers. Rear-side light-induced degradation (LID) is also a potential risk.
Bifacial Technologies There are different types of bifacial modules, including glass-glass and glass-backsheet modules. There are also different mounting options for bifacial modules, such as raised or tilted mounts, which can improve their energy production.
The following table summarizes the different bifacial technologies and their characteristics:
| Technology | Characteristics |
|---|---|
| Glass-glass | More durable and less prone to degradation than backsheet |
| Glass-backsheet | Lighter and cheaper than glass-glass modules |
| Transparent backsheet | Allows for light to be captured from both sides and below |
| Tilted mount | Increases energy production through better albedo |
| Raised mount | Increases energy production by reducing shading effect |
Conclusion Bifacial PV modules are a promising technology that can increase energy production and reduce the LCOE of solar projects. However, there are also potential risks associated with their use, such as weight, corrosion, cell fracture, and degradation. As the cost gap between mono- and bifacial modules continues to decrease and new technologies are developed to address these risks, bifacial modules are likely to become an increasingly popular option in the solar industry.