Bifacial PV panels are the hot topic trending in the PV world since 2019. This year, in 2020, we get asked about bifacials in almost every meeting with our clients — because everyone always wants to have the latest technology. But are bifacials actually worth all the hype?
What are bifacial PV panels?
Bifacial PV panels are solar panels that have the ability to produce electricity from both sides of the panel. A typical PV panel has a backsheet that is made of polymer. On the other hand, bifacials have both the front and rear sides of the solar cells exposed.
How do bifacial PV panels work?
On a highly reflective surface, some manufacturers claim to have up to 30% (with solar tracking system) production increase coming from the rear side of the panels. However, there has to be sufficient gap between panel and reflective surface for any sun irradiance to bounce back.
As such, bifacials are most suitable for solar farms, as there will be significant gap between panel and ground. However, the ground has to be at best sandy and white to reflect sun irradiance. Grass does not reflect sun irradiance well. On the other hand, bifacials are least suitable for rooftop systems. There is very little gap between panel and rooftop, although some rooftops may be highly reflective.
Advantages of bifacial PV panels?
- Bifacial PV panels are made with glass on both sides. As such, bifacials are more durable compared to a conventional PV panel. Some manufacturers even offer an extended warranty because of this.
- It is possible to install bifacials vertically. This arrangement is especially useful for installations where space is limited, as the sky has no limits. Vertical installation will instead have 2 peaks — sunrise and sunset — which is not entirely ideal as compared to 1 peak during the afternoon sun.
- Some bifacials are made of glass without any aluminium frames. This will make the panels more durable to any chemical erosion. Having said this, conventional panels with aluminium frames are already considered to be very durable.
- Because there are no aluminium parts, bifacials do not need grounding.
Disadvantages of bifacial PV panels?
- As of now, the technology is still considered to be expensive, especially when the rear side is also made of glass. Furthermore, the unreliable production from the rear side of the panel does not justify the added cost.
- Bifacial PV panels are heavy because of the additional glass panel.
- Special mounting system is needed for bifacials as they are not framed with aluminium. This mounting system is expensive and is currently not widely available.
- Bifacial PV panels are still in the initial phase of development, and just like any new technology, will be very costly. However, there will come a time in future that prices for bifacials will drop and make more economical sense.
- Bifacials are most useful for solar farms as there is a significant gap between reflective surface and panel. With similar logic, bifacials are least useful on rooftops.
- Even when used for solar farms, the added costs for using bifacials will likely not make economical sense.
- All in all, for any PV systems, it all comes down to cost vs returns. Currently, conventional PV panels are most viable due to its affordable low cost.
If you have any questions, kindly Our SEDA certified Solar PV Engineers will be glad to answer them for you. Simply get in touch with us here for more info.