What kind of material do solar panels form? What is their average lifespan and what kind of impact do they have on the environment?
Each of these questions brings us back to a fundamental theme: are solar panels recyclable?
Considering the increased production of new renewable energy systems, it is fair to ask how they interact with the environment. We know that the panels are designed to withstand up to twenty years, and that they allow us to fight climate change.
All we need to know is if solar panels can be considered as actually recyclable and, above all, how the disposal process works. Let's find out together, starting from the set of materials that allows them to be built.
What are solar panels made of?
To actually understand how much solar panels can be defined as recyclable, it is important to start from their basic constitution.
In general, each panel is produced using: glass, silicon cells and metal structures. In turn, the silicon cells can be monocrystalline or polycrystalline.
- Monocrystalline silicon is often considered to be more efficient, because it manages to create more resistant systems. The final color of the panel is quite dark. Their degree of efficiency ranges from 15% to 20%.
- Polycrystalline silicon is cheaper, and relies on different crystals. Typically, this type of solar panel has a blue tint. Their degree of efficiency ranges from 13% to 16%.
Speaking instead of the average duration of these materials, we can say that most solar panels last about twenty years. Several manufacturers guarantee buyers a resistance of 25 years, with a slight loss of efficiency in the last years of activity.
What are the damage to the environment?
One of the most dangerous elements regarding the environmental impact of solar panels is directly related to their production.
The creation of solar panels begins with the extraction of silicon, which is derived from silica - itself derived from quartz sand.
Almost all major extractions take place in China, and involve a high production of carbon (Carbon is not exactly good for the environment, but it is essential for mining. To release the silicon, we need to bring the coal to a high temperature so that we can combine the carbon with the silica).
Thankfully, the latest silicon manufacturing methods have succeeded reduce by 12 times the carbon footprint. However, the amount of carbon produced is still too high to be ignored.
At the end of its life, a solar panel releases cadmium, lead, indium, molybdenum and tellurium into the ground. However, the quantities are too low to constitute a concrete environmental risk. (an interesting one was conducted in this regard search)
If manufacturers manage to lower their carbon footprint even further, solar panels could turn into an even more beneficial element for environmental health.
Thanks to the work of the designers, we know that solar panels can be recycled, and that they can be transformed into new polycrystalline panels.
It is necessary to reconstruct the metals, but the process is not very aggressive and manages to make them maintain their degree of purity. The same also applies to silicon, which is basically a nonmetal (a material that has some aspects of metals).
Lately, Europe has forced manufacturers to supply recycling options for their solar panels. The goal is to reduce the environmental impact and encourage a more "green" style of production.
Unfortunately, the United States has not made the same step. This means, that still 76% of producers does not recycle or reuse its panels.
The recycling process
There is still no "official" method for recycling solar panels.
A project carried out in collaboration with the Fraunhofer Institute for Solar Energy Systems was able to increase the efficiency of a solar panel after going through the recycling process. However, it did not provide unique answers for all panels.
To deal with the recycling process, it is necessary to identify the individual modules that are still usable, to take care of the extraction of the individual components, of the extraction of certain raw materials, taking care not to damage anything.
Each process brings with it additional costs, which must then be taken into account. Basically, recycling solar panels is quite difficult. There is a need for increased incentives and research into the best recycling methods, especially considering how many solar panels there are still to be built.