Looking at a solar panel from afar and imagining how it is made is very difficult. What materials are used to create them? Where are they produced? What is the environmental impact of solar panels? I will decipher all of this with you.
Materials used to make a solar panel
For most solar panels, silicon is the raw material used to manufacture photovoltaic cells. This material has two fascinating characteristics: it is photosensitive and semiconductor.
There are two essential things to know about silicon:
1. It is the second most common element on Earth. The first is oxygen. The earth’s crust is made up of 28% silicon!
2. It does not occur naturally in its pure state. To obtain silicon, it is therefore necessary to go through a refining stage to exploit it. It is generally extracted from quartz or sand.
China is the country that manufactures the most silicon in the world. Nearly 71% of world production comes from this country.
The manufacture of silicon requires a reduction process at very high temperatures. The ingots obtained by cooling are then cut into thin slices. They make it possible to create photovoltaic cells.
Other materials are needed to manufacture solar panels:
An aluminum frame;
A protective glass plate;
Plastic to encapsulate cells;
Copper or silver connections.
Panel manufacturing is generally automated.
The stages of manufacturing the panels
The manufacturing of photovoltaic panels follows a set of steps. The formation of silicon is the first of these. The manufacture of silicon requires a reduction process at very high temperatures. Thanks to this chemical reaction, “ingots” can be formed and then cut into thin slices to obtain the desired shape to create photovoltaic cells.
Later, a chemical treatment is applied to the ingots so that they do not reflect light. The panel’s surface is no longer wholly smooth but comprises tiny pyramids. They will allow a greater quantity of light to be absorbed.
Phosphorus is then deposited on the front of the panel at a very high temperature. A circuit is printed on the surface so that current can be transferred into the electrical circuits inside your home.
Finally, the different photovoltaic cells created are connected by welding. They are encapsulated under tempered glass and surrounded by an aluminum frame. A junction box is placed over the polyester film on the back of the panel. The inverter can be connected to it at this location.
The main countries producing solar panels
The main producer of solar panels today is China. This country invested massively in solar energy in the early 2000s. This bet paid off because 70% of producers are now of Chinese origin.
Other countries like South Korea, the United States, and Germany are starting to emerge in panel production. France is manufacturing more and more panels on its soil, with companies such as Voltec Solar, Systovi, and DualSun.
The environmental impact of solar panel manufacturing
The manufacturing itself
Many questions arise about the ecological impact of the manufacturing of solar panels. The first concerns the energy deployed for the creative process.
Indeed, transforming quartz into silicon requires a very high temperature and, therefore, a significant amount of energy. It is estimated that it takes 12,000 kWh to produce one ton of silicon. It must be added that this electricity comes mainly from fossil fuels used by most Chinese factories.
The manufacture of solar panels is indeed very energy-intensive. However, it must be considered that once produced and installed, a panel has green electricity for 30 to 40 years. Its overall impact is, therefore, largely positive.
End of life of panels
This is excellent news: a solar panel is 95% recyclable once it no longer works. A large part of its components are used to manufacture new photovoltaic panels. Thus, the ecological impact of panel manufacturing is further reduced, and the circle is virtuous.
Solar panels are mostly made from silicon, glass, plastic, copper, and silver connections. China remains the world’s largest producer of panels, although more and more manufacturers from other countries are beginning to compete with them seriously. It should be remembered that even if their manufacturing is energy-intensive, their overall results are mainly positive because they make it possible to produce green electricity for 30 to 40 years. They are also 95% recyclable at the end of their life.
What temperature is needed to transform silicon?
The carbon reduction process, essential for the transformation of silicon, requires a temperature of more than 2,000°C. After this process, the purity is 98% to 99%. Further refining steps are then required to increase its purity to 99.9999%.
What is the average weight of a solar panel?
A panel weighs between 10 and 12 kg, depending on its size and components. The weight of the bindings must be added to this. So, count between 15 kg and 20 kg for a complete installation.