Bifacial modules, which date back to the 1960s, are an older advancement of solar panel technology. It is also one of the most recent breakthroughs. However, several analysts believe it is now on track to become the new solar industry trend and will soon become the norm. Bifacial modules’ high energy production has revolutionized the solar power industry. Not all revolutions, however, mean large-scale events that change and shake foundations. Some revolutions are subtle, tend to be small, and can be difficult to detect and execute at times. Their results, on the other hand, can be overwhelming. This is how bifacial technology is influencing the design of PV fixed tilt and tracker systems, as well as PV power plants.
Understanding Bifacial Solar Module
Solar power is created from both sides of the panel in bifacial modules. Bifacial modules display both the front and backside of the solar cells, whereas conventional opaque-backsheeted panels are monofacial. When bifacial modules are mounted on a highly reflective surface, similar to a white TPO roof or light coloured stones laid on the ground, some bifacial module manufacturers say that the extra power produced from the rear will result in an increase in output by 30%.
Bifacial modules are available in a number of types. Some of them are framed, while others are not. Some have dual-glass backsheets, while others have flat backsheets. The majority of the time, monocrystalline cells are used, but polycrystalline designs are also available. One thing remains constant, that is, power is created from both the sides. Modules that are frameless and dual-glass that expose the backside of cells but are not bifacial are also available. Contacts or busbars are present on both the front and back sides of true bifacial modules’ cells.
The sum of the energy produced by the module’s front and back sides can be used to measure the power output of a bifacial module. The front side of conventional monofacial modules is responsible for all of the module’s energy generation. This energy production can be calculated with precision. The energy production of bifacial modules is also influenced by the irradiance that strikes the module’s back side.
To comprehend the Bifacial Gain, we must assume two things, first, the sunlight that reaches the rear side of a module behaves differently than the sunlight that reaches the front side. And second, that the rear side power conversion efficiency varies from the front side power conversion efficiency. For better understanding, the following two concepts have been introduced.
- The bifacial ratio is the proportion of irradiation reaching the rear side of a module to the irradiation reaching the front side.
- The ratio of the energy conversion efficiencies of the rear and front sides of a module is known as module bifaciality.
It is important to remember that bifaciality is a module trait, while the bifacial ratio is directly proportional to the irradiation on the module’s back and front sides. This implies that by placing a module in such a way that the irradiation on the back side of the module is maximized, the Bifacial Gain of the module can be increased.
To optimize the energy output of the backside of a module in a PV power plant, we must first consider the factors that can increase the amount of irradiation that enters the module’s back side. The rear modules comprise diffuse irradiation that is present in the atmosphere and the irradiation that is available on the ground and other surfaces. The albedo of a surface is the percentage of incident irradiation that is reflected by it.
The issue is that energy forecasting tools designed for monofacial power plants do not accurately predict the output energy of a power plant using bifacial modules. To estimate the energy output and determine which elements affect module rear-side power generation, actual plant measurements must be used. After doing a comprehensive analysis of all the factors that impact the irradiation that reaches the rear modules are albedo, module heights and the distance between the different module rows and the various elements that are a part of the rear side of the tracker structure.
When determining whether or not a bifacial solar tracker setup is right for your next location, do a lot of research on the albedo and seasonal changes. Maybe do some calculations to see if changing or improving the site’s albedo would pay off over time. With the lower cost of bifacial modules, all of those small performance advantages could add up to a significant difference in expected results. Bifacial modules are the industry’s future because they have a high power density, resulting in substantial cost savings, a high energy yield, and a lower temperature coefficient. Furthermore, bifacial modules extract energy from the back side as well, resulting in a higher energy yield.