Bifacial modules: The two sides of a solar module
Bifacial solar modules use both direct irradiation on the front side and indirect light on the back side to generate electricity. In our blog post we take a closer look at how bifacial modules work.
In general, we can think of a bifacial module as a standard module. A glass panel on the back side of the module allow both unused light passing through the module and reflected light from the environment to be captured by the cells on the back side as well.
In a bifacial solar cell, the full aluminum back surface array is replaced by an aluminum grid. This grid brings high transparency to the back surface of the module. Indirect light can thus be captured by the solar cell on both sides.
Source: SoliTek
Factors to influence the additional yield:
Factors such as the so-called albedo value (reflectivity) and the type of installation of the module have a significant influence on how high the additional yield generated by the rear side turns out to be. The albedo value indicates what proportion of the incident radiation is reflected: the higher, the greater the reflected irradiation.
For example, the albedo is about 10% for high sun over deep water, 10% - 30% for meadows, and up to 75% - 95% for fresh snow.
Another factor is the so-called bifaciality, which expresses the quality of the back side in terms of power generation compared to the front side. Bifacial modules usually have a bifaciality between 70 and 95%. For example, a bifaciality of 95% means that under the same conditions, the back side generates only 95% of the front side power.
The distance of the module from the ground also have a significant impact on how much additional yield is generated by the rear side.
With the right conditions, an additional yield of between 5% and 30% can be achieved compared to conventional monofacial PV modules. Especially in the mornings and evenings, the rear side makes the greatest contribution.
Further advantages at a glance:
- Ideal for flat roofs and outdoor installations
- Better low-light performance, as diffuse light can be absorbed by the back of the module
- Better performance than monofacial modules, reduces electricity generation costs
- Lower annual degradation (0.05% less than monofacial modules)
- Excellent temperature coefficient
There are many possibilities for the use of bifacial solar modules:
- Module elevations on flat roofs
- Vertically mounted ground-mounted systems
- Terrace and balcony railings
- Soundproof walls
- Glass canopies on terraces
- Facade glass constructions
Are you looking for bifacial modules?
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