Usually the solar cells we see are single-sided solar cells, which can well accept direct sunlight and convert light energy into electricity. However, they can't do anything about some reflected sunlight. To take advantage of the reflected sunlight, double-sided solar panels must be used.

Bifacial solar panels can generate more electricity than conventional solar panels, but only if they have room for reflected light to reach the back of the panel. This means that they work best in a specific location, rather than placing them right on the roof. If you're mounting your solar panels on a pergola or ground mounted system, a double-sided panel might make perfect sense.

How do double-sided panels work?

A new thermodynamic formula shows that double-sided solar panels generate an average of 15 to 20 percent more solar energy than today's single-sided solar panels, taking into account different terrains such as grass, sand, concrete and dirt. This formula, developed by two physicists at Purdue University, can calculate in minutes the maximum amount of electrical energy a bifacial solar cell can generate in a variety of environments (as defined by thermodynamic limits).

It is understood that there is also enough light reflection on the back of the panel to generate electricity. To get the most out of double-sided panels, there are several key factors to consider.

First, the more reflective the environment around the panels, the more energy they generate. Light-colored environments will reflect more light and improve performance. "We found that when grass turns brown, it becomes more reflective and snow is very reflective," one researcher said in a report from the National Renewable Energy Laboratory. Consultancy Wood Mackenzie It also means that desert countries like Australia, which have a lot of reflective sand, can make better use of double-sided panels than their neighbors, the report said.

Second, there needs to be room for the reflected light to reach the back of the panel. This means that the double-sided panels don't make sense on the roof, as they are almost clinging to the roof. They're best used in large commercial installations, where they're suspended from poles with plenty of room for light to bounce off the back.

Double-sided panels outperformed traditional single-sided panels throughout the year. Under ideal conditions, double-sided panels can generate 27% more energy.

Double-sided panels can be used at home

Bifacial solar PV panels don't cost much more than other solar panels, so if you have the right place, they're an attractive option. Even if there is no benefit to installing them on the roof, in some cases homeowners may still opt for double-sided panels.

Bifacial panels may be a good option if the solar panels are installed on the ground rather than on the roof. This is especially true if you live in a snowy area, or if you can mount it on a more reflective surface like sand.

It may also be beneficial if a double-sided panel is used to build a covering on the exterior area. A pergola or awning with open space below will be far enough from the ground to allow reflected light to reach the back of the panel. Creative people may find other better ways to deploy double-sided panels.

Although not helpful in most residential applications, double-sided panels are another tool that can help you absorb more energy from the sun. Using them in the right circumstances can help you reach your energy goals for a fraction of the extra cost.