Necessity is the mother of invention, and also of innovation. What greater necessity could there be the need for a safe planet to live upon. Climate change has driven no end of technological advancements, including the subject of this article: the bi-facial solar panel.
Figure 1: Solar panels atop a car port [1]
Mono- vs. Bi-Facial, What’s the Difference?
Most solar panels that we can see anywhere, from solar farms spanning across acres, to mini panels on an automated radar speed sign, are mono-facial. In mono-facial panels, semiconductors within the panel generate electricity from photons within sunlight which hits the front of the panel. These semiconductors can only absorb light from the front of the panel, however. The back of the panel is made of an opaque layer, meaning that light inside the panel that is reflected is wasted.
The bi-facial panel innovates on this design by replacing the opaque backing with a reflective surface and semiconductors which can absorb sunlight coming from both in front, and behind [2]. This means that the same amount of sunlight, a greater amount of energy can be produced. A greater percentage of the sunlight within the panel can be utilised, and further to this, sunlight that reflects off the surface below the panel and hits the underside of the panel can also be absorbed.
The Advantage of Being Two-Faced
Bi-facial solar designs first arose around fifteen-years after mono-facial designs. Bi-facial panels have remained a minority among the panels used within solar developments due to their higher cost when compared to the simpler design and reduced maintenance required. In 2020, only 20% of solar cells globally were bi-facial, however the International Technology Roadmap for Photovoltaics predicted that bi-facial panels would overtake mono-facial panels in popularity by 2027 [3].
The higher energy efficiency of bi-facial panels makes them a good option for developments where space is at a premium, such as rooftop developments where the scope for installation is constrained by the architecture of the building. The dual-glass design tends to lead to greater durability and thus longer life spans before panels need to be replaced. As such, one can see why this innovation has been popular.
But are Bi-Facial Panels Worth It?
As any good economist will tell there is no free lunch, and bi-facial panels have their draw backs. Alongside a higher upfront cost, due to a more complex design, the installation process can also be more costly [4]. Whether this can be offset via the increased energy generation of the panel design, is an economic decision that must be decided upon on a case-by-case basis. However, as technology advances and the production process becomes more efficient, costs will reduce, allowing greater uptake.
The path to a green energy future will not be simple, but will be hastened by technological innovations that make our systems more efficient. The bi-facial solar panel is just one example of necessity driving innovation further.
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References
[1] Kindel Media (October 2021) on Pexels.com. Last accessed on 14th August 2024. Available at: https://www.pexels.com/photo/cars-parked-on-parking-lot-under-the-solar-panels-9799756/
[2] https://freyrenergy.com/bifacial-vs-monofacial-solar-panels-which-solar-panel-system-reigns-supreme/
[3] https://resources.solarbusinesshub.com/images/reports/248.pdf
[4] https://www.renogy.com/blog/bifacial-solar-panels-disadvantages-and-advantages/
