Waste Photovoltaic Panels Expected to Be 100% Recycled？

Energy research organization Wood Mackenzie released a report that since 2020, the world's annual new installed capacity has reached 125GW. As the global photovoltaic installed capacity continues to rise, the number of photovoltaic panels (hereinafter referred to as PV panels), which are the core components of photovoltaic power generation, is increasing day by day. In 2025, my country's photovoltaic panels began to enter a period of intensive scrapping, and the total amount of scrapped PV panels is expected to reach 20 million tons in 2050. It is understood that photovoltaic panels contain glass (about 70%), aluminum (about 10%), adhesive sealant (about 10%), silicon (about 5%), silver, gallium, indium and other rare metals (about 1%), etc., which have extremely high recycling value. In addition, photovoltaic panels also contain heavy metals such as lead and cadmium and organic matter such as adhesive sealant, which will pose a great threat to environmental safety if not handled properly.

In order to efficiently recycle available resources and protect the environment, the recycling and reuse of scrapped PV panels has become a hot topic of research at home and abroad. At present, the pretreatment technologies that have been developed include thermal decomposition, mechanical treatment, chemical treatment, acid leaching, vacuum distillation, etc., but they all have certain limitations. For example, the thermal decomposition method can only process cells with a thickness of ≥ 400μm, the mechanical treatment method has problems such as unstable purity of recycled products, high energy consumption, and large land area, and the chemical method does not consider the removal of the frame and the recycling of silicon wafers, and the collection and treatment of a large amount of waste liquid after treatment is difficult. Since 2006, companies in developed countries such as the United States and Germany have gradually started the industrialization of PV panel recycling, such as First Solar in the United States and GeltzUmelt-Technology in Germany. In order to regulate the recycling of scrapped PV panels, the EU has issued a series of regulations such as the Waste Framework Directive (2008/98/EC) and the Waste Transportation Regulations ((EC) No1013/2006). The EU Regulation on Waste Electrical and Electronic Products, revised in 2010, took the lead in including photovoltaic panels in the management scope. Compared with developed countries, the recycling of scrapped photovoltaic panels in my country is still in the stage of technical exploration, and relevant laws and policies are also in a blank period.

In 2018, the first solar panel recycling plant in Europe and even the world was officially put into operation. It is capable of disassembling, sorting, processing and recycling 95% of the materials in crystalline silicon photovoltaic panels: 2/3 of the glass is recycled into broken glass and sent to glass manufacturers; aluminum frames are sent to aluminum refineries; waste plastics can be used as fuel in cement plants; recycled silicon can be reused in the precious metal industry; the remaining cables and connectors are crushed and sold in the form of copper beads. However, some scholars have pointed out that the world's first scrapped PV panel recycling plant uses a method of burning and decomposing the adhesive layer between the glass and the backplane. It is not only energy-intensive and low-capacity, but also has a carbon footprint. At the same time, due to cross-contamination during recycling, the recycled glass can only be used for laying floors, so the recycling rate of materials is not very high; and the Japanese recycling plant uses chemical cleaning methods, which also causes high pollution.

The National Tainan University in Taiwan, China, has collaborated with the industry to develop a method for 100% physical recycling of photovoltaic panels, which is low-cost and pollution-free, and the recycled materials can also be made into new photovoltaic panels. Once this industry-university cooperation result is released, large-scale recycling operations can be realized. Taiwan estimates that 15.3 million tons of scrapped photovoltaic panels will be produced in 2050, and recycling becomes particularly important. The National Tainan University team studied recycling and utilization, taking the circular economy as the starting point, making full use of the excellent stability of photovoltaic panel materials, and using a physical slightly heated method to destroy the surface affinity of the material, so that the adhesive layer between the glass and the back panel can be disassembled and separated, and then recycled separately by grinding. The team said that although there is also heating during the processing of scrapped photovoltaic panels, the temperature is low, and it only takes 2.5kW•h to recycle an average photovoltaic panel, which is much more energy-efficient than the European combustion method, and the materials in the photovoltaic panels can also be recycled separately, without cross-contamination problems, and 100% reuse can be achieved. The team proposed a more comprehensive recycling plan: since photovoltaic panels contain more than 70% high-transmittance glass, they can be processed and made into grooved glass, which can be used as photovoltaic wall building materials or laid on sidewalks to continue generating electricity; silicon wafers can be recycled into powder and used as Heat Dissipation materials, and the precious metal silver contained in them can also be reused; the PVDF poly vinylidene fluoride in the backplane can also be made into Teflon, thereby maximizing the recycling value.

Key words: PV, photovoltaic panel