The energy industry has been undergoing fundamental changes, with the gradual shift towards renewable energy sourcing being readily apparent. However, not everything that appears sustainable remains so at the end of its life cycle. At least, that's the most common concern about photovoltaic (PV) solar panels. They are a sustainable energy source that relies solely on solar radiation and can power our homes. But what happens if solar panels fail to function effectively? Explore their journey through the recycling process in the infographic below:
Lifespan of solar panels
How long do solar panels last? This is a question that most people consider when thinking about solar panels. According to research, the lifespan of a solar panel is approximately 30 years.
Over the lifespan of a photovoltaic panel, its power capacity may decrease by 20%. The maximum efficiency decline is 10% in the first 10 to 12 years, and up to 20% by the time it reaches 25 years. These figures are guaranteed by most manufacturers.
Nevertheless, experience shows that, in reality, efficiency only decreases by 6% to 8% after 25 years. Therefore, the lifespan of solar panels may be longer than officially stated. High-quality photovoltaic panels can even last 30 to 40 years, and although efficiency decreases, they can still function normally afterward.
Disposal of solar panels
From a regulatory perspective, solar panel waste still falls under the general waste category. The only exception is at the EU level, where photovoltaic panels are defined as electronic waste under the Waste Electrical and Electronic Equipment (WEEE) Directive. Therefore, this directive, among other legal frameworks, also regulates the management of photovoltaic panel waste.
Solar cell manufacturers are legally bound to meet specific legal requirements and recycling standards as technologies for recycling solar panels begin to emerge, to ensure that solar panels do not burden the environment.
Solar panel waste
In fact, without recycling processes, 60 million tons of solar panel waste will end up in landfills by 2050. Since all solar cells contain some amount of toxic substances, this will truly become a less sustainable energy source.
Therefore, the widespread belief that solar panels are not recyclable is a myth. However, this is a process that requires time and widespread implementation, and further research is needed to fully realize the potential of recycling all solar panel modules. Therefore, close collaboration between design and recycling companies is essential to ensure recycling capacity through thoughtful eco-design.
Solar panel recycling process
There are two main types of solar panels that require different recycling methods. Both types—silicon-based and thin-film-based—can be recycled using different industrial processes. Currently, silicon-based panels are more common, but this doesn't mean that the materials used in thin-film batteries have little value.
Research on the recycling of solar panels has yielded numerous technologies. Some of these technologies have even achieved an astonishing recycling efficiency of 96%, but the future goal is to raise the standards even higher.
Silicon-based solar panel recycling
The recycling process for silicon-based photovoltaic panels begins by disassembling the actual product into aluminum and glass components. Almost all (95%) of the glass can be reused, while all external metal parts are used to reshape the cell frames. The remaining materials are processed in a 500°C thermal processing unit to loosen the bonds between the cell elements. Due to the extreme heat, the encapsulating plastic evaporates, allowing the silicon cells to be further processed. Accompanying technologies ensure that even this plastic is not wasted; it is reused as a heat source for further thermal processing.
After heat treatment, the green hardware is physically separated. 80% of it can be easily reused, while the remainder is further refined. Silicon particles, known as silicon wafers, are etched away with acid. The fragmented silicon wafers are melted down and reused to manufacture new silicon modules, achieving a silicon material recycling rate of 85%.
Thin-film solar panel recycling
In contrast, the processing of thin-film-based panels is more drastic. The first step is to put them into a shredder. Then, a hammer is used to ensure that all particles are no larger than 4-5 millimeters, which is the size at which the laminate holding the internal materials together breaks and can therefore be removed. Unlike silicon-based photovoltaic panels, the remaining material consists of solid and liquid materials. To separate these materials, a rotating screw is used, which essentially spins the solid portion inside a tube while the liquid drips into a container.
The liquid undergoes precipitation and dehydration processes to ensure purity. The resulting material then undergoes metal processing to completely separate the different semiconductor materials. The final step depends on the specific technology used in panel production; however, on average, 95% of the semiconductor materials are reused.
The solid material is contaminated by a so-called intermediate layer material, which is lightweight and can be removed by vibrating the surface. Finally, the material is rinsed. What remains is pure glass, saving 90% of the glass elements and facilitating remanufacturing.
Future Benefits of Solar Waste Management
Now that we know solar panels can be recycled, the question is what other economic benefits (if any) they bring. Clearly, a proper solar panel recycling infrastructure will be needed to manage the large volume of photovoltaic modules that will be disposed of in the near future. Once implemented, we will see some positive factors and new opportunities in the economy.
By 2050, solar recycling will not only create more green jobs, but also generate approximately £11 billion in recycling value. This massive influx will enable the production of 2 billion new panels without the need for investment in raw materials. This means that approximately 630 GW of energy could be generated simply by reusing previously used materials.
As solar energy prices continue to decline, more and more households and businesses are choosing to invest in solar power systems. As a result, more economic opportunities will emerge in the solar cell recycling sector.
