In the race to develop the most efficient type of solar panels, manufacturers have developed bifacial solar panels. This type of panel has solar cells on both sides which allows the technology to capture more sunlight leading to greater solar cell efficiency compared to traditional solar arrays.
How Do Bifacial Solar Panels Work?
Lets first dig deep into how bifacial solar panels function. The top and bottom solar cells on a bifacial solar array function differently. The top solar cells function like a conventional solar panel array. They face the sun, so they capture incident sun rays directly, absorbing only certain wavelengths.
On the other hand, the bottom solar cells absorb light that is reflected off the ground. Since white or light colors reflect better than dark colors, painting a white or silver surface on the roof or driveway under the panels is encouraged. According to a study by Burns & McDonnell, white surfaces reflect more than 80% of this light while grass only reflects 23%.
How Is Bifacial Solar Panels Installed to Increase Efficiency?
To understand the difference, let’s first uncover how a monofacial solar array is set up. A monofacial solar panel system, or a group of one-sided solar panels, are placed in racks parallel to a surface such as a rooftop. Unlike single-sided panels, bifacial solar panels are installed on a tilt because they produce more energy when they are angled off of the roof or ground at varying degrees.
Below are three benefits of the titled installment of the bifacial solar array.
1. More sunlight to absorb
In these types of titled installations, there is a great amount of reflection. Because sunlight bounces off of all objects reflectively at many different angles, bifacial solar panels are able to capture more of it.
2. Productive on cloudy days
Because of the point above, bifacials can be productive on cloudy days while monofacial solar cells are at a greater disadvantage when there isn’t direct sunlight. Also, bifacials are less susceptible to weather damage because they are more durable. According to the Solar Magazine, because they are more durable than conventional solar panel systems, warranties for bifacial solar panels are typically 5+ years longer (that is, 30+ years versus 20–25 years).
3. Two energy peaks a day
A titled installation can also produce two energy peaks throughout the day based on their placement. For example, half of the bifacials in an array can be tilted toward the east to capture sunrise and morning rays. The second half can then be tilted to the west to soak up afternoon intensity and sunset rays.
Another installation that can achieve this is a vertical installation. During each peak, the reflection of sunlight on the other side of the solar panels will also contribute to energy production.
How Much More Efficient is a Bifacial Solar Array?
When we say efficiency, we are referring to how a solar cell takes the amount of solar energy it received and converts it into electrical energy. Although bifacials produce more electricity than monofacial panels, it definitely isn’t double the efficiency although solar panel manufacturers are working to make that happen in the future. Bifacials can increase energy efficiency by 11% compared to a conventional solar panel system, according to our study. And with a solar tracking system that tilts solar cells continuously toward the sun, the bifacial solar cell efficiency can be as high as 27%.