echnological development has allowed, and continues to do so, the evolution of photovoltaic solar panels. There are different types of panels depending on the material used in the photovoltaic cells, and cost and efficiency may be the fundamental factors when choosing the most advantageous option. Undoubtedly the initial investment is the most important effort, and what is expected to be recovered with the economic savings obtained . What types of plates does the market offer? Which is the best option? What do you think will be the evolution, in terms of prices and technology, of photovoltaic panels? Participate with your comments.
What type of photovoltaic panels are the most efficient and profitable?
In the previous post, we saw what the photovoltaic effect consists of: moving electrons when the light hits, thus generating an electric current, thanks to the electric field that is generated in the photovoltaic cell, because it is made up of two sheets of a semiconductor material, but of opposite charges each. Therefore, the photovoltaic cell will be the main element of the photovoltaic module, capable of converting the light energy captured by the panel into electricity, in the form of a photon.
What materials are used in the manufacture of plates?
Although the most widely used material for the manufacture of photovoltaic cells is Silicon, there are other alternatives. But in order to choose the most suitable option, it is important to take into account certain factors when choosing the semiconductor material of the panels:
Firstly, the absorption coefficient , which determines the cell’s ability to absorb the solar radiation that falls on it, and therefore its efficiency or performance . Remember that solar radiation is an electromagnetic wave, which propagates through a vacuum and through matter. Therefore, whether solar radiation is absorbed to a greater or lesser extent depends, on the one hand, on the wavelength of light that the material absorbs; and on the other, the absorption capacity of said material.
The ordering of the crystalline structure of the cell material is also a determining factor. The arrangement of the atoms determines the structure of the material, and has to do with the moving electrons that generate the electric current.
Finally, the production of the panels , from the point of view of its cost and how it is manufactured, that is, if the process is more or less complex, depending on the selected material.
Image: solar panel manufacturing chain; www.solar-world-usa.co
The weight of the panels is an aspect that has evolved over time (the evolution of photovoltaic cells for energy). Technological development has made it possible, over time, to manufacture lighter panels, and on the other hand, it is also possible to include, as raw material, recycled content from other panels already used, in the composition of the photovoltaic cells.
Types of plates used
As we have commented at the beginning of this post, the main element in the manufacture of photovoltaic panels is the photovoltaic cell. We have also seen that it depends on several factors, therefore, what alternatives do I have when choosing the most suitable type of plate?
Well then, when the selected material is Silicon , three types must be differentiated, depending on their crystalline structure: monocrystalline, polycrystalline and amorphous . The yield of the cells for any of the three options is relatively similar, ranging between 6% and 17%. Of the three options, the panels formed by monocrystalline silicon cells , are the ones with the highest performance (13-17%), although their production is the most complex, since it requires more time and energy consumption in its manufacture, and it is also expensive. By contrast, amorphous silicon panels, they are simple to manufacture and cheaper than the other two, they are in the form of a thin sheet of silicon, which is deposited on another sheet of glass, metal or plastic, but the yield is much lower (6-8%). There are currently companies trying to improve the performance values of thin amorphous silicon cells. In this article he explains it: What is amorphous silicon? Why is it so interesting now?
The manufacturing process of polycrystalline silicon cells differs from that of monocrystalline silicon cells, and less material is wasted in their manufacture. The cells are square and their color is not uniform, since it presents different shades of blue. Its absorption capacity is good due to its blue color, and its yield reaches values between 11% and 15%.
Cost and efficiency are the decisive parameters when choosing one type or another , and in this sense, monocrystalline silicon panels can win the game , followed by polycrystalline ones. The reason is that monocrystalline cells have higher performance and need less space (capture surface), while thin cells, despite being cheaper, are less efficient, and therefore more space needs to be covered. , and therefore ultimately more material has to be used, to produce the same amount of energy ( Why choose monocrystalline technology , www.thesolarco.com).
Image: left and central cell of monocrystalline silicon, uniform dark blue or black color; right cell of polycrystalline silicon, blue-gray color. uksolarcontact.com
Image: Amorphous silicon cell, brown color
Other types of materials such as sulfur and arsenium can also be used . The first material is used in combination with either copper or cadmium in the production of thin-film cells , although other materials can also be used to manufacture this type of cell. Its performance is similar to that of amorphous silicon cells: very low.
The material with which the best yields are obtained by far is arsenium in combination with gallium. The reason is that it is a stable material, which works despite the fact that the cells are thin. On the contrary, it has a high cost, since it is not easy to have this material.
What technology convinces you the most? What is your opinion? How do you see the future of photovoltaic solar energy in Spain, and its application in residential use, for example? Participate with your comments, and if you found it interesting, share it among your contacts.