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Analysis of material recovery from silicon photovoltaic panels

Analysis of material recovery from silicon photovoltaic panels
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Abstract: 
Lifecycle impacts of photovoltaic (PV) plants have been largely explored in several studies in the scientific literature. However, the end-of-life phase has been generally excluded or neglected from these analyses. It is expected that the disposal of PV plants will become a relevant environmental issue in the next decades. An Italian company is currently developing the project FRELP - Full Recovery End of Life Photovoltaic- as part of the European “LIFE” programme. The FRELP project focuses on the development of an innovative process based on a series of mechanical and chemical treatments to recycle/recover waste crystalline-silicon (C-Si) photovoltaic (PV) panels. Thanks to the FRELP processing several materials can be sorted from 1 tonne of PV waste including: glass (98%), aluminium (99%), silicon metal (95%), copper (99%), and silver (94%) for a total quantity of 908 kg. Some of these materials (e.g. silicon metal, antimony, chromium and fluorspar) are considered as Critical Raw Materials for the European economy, having high economic importance and high risk of supply. The present report describes the application of Life Cycle Assessment (LCA) methodology to analyse the innovative process developed within FRELP project. The system boundaries of the LCA were set from the PV waste collection until the production of recyclable materials. Environmental benefits (i.e. credits) due to the potential productions of secondary raw materials have been accounted by expanding the system boundary. The benefits of the recycling process were compared to impacts due to the production of raw material and manufacturing of the PV panels. The report shows that, when waste materials are recycled to produce secondary raw materials, relevant environmental benefits can be obtained. The LCA methodology was also applied to assess the environmental performance of the innovative recycling process in comparison with the current treatment of PV waste in generic Waste of Electric and Electronic Equipment (WEEE) recycling plants. The results proved that this innovative recycling implies higher impacts for the processing but much higher benefits in terms of recycled materials. Relevant net benefits have been estimated. The LCA identified some hot-spots of the recycling process. Transport has been found to have an important contribution to all life cycle impacts. Finally, the high efficiency and quality of glass separated through the FRELP processes could be used for high quality application (i.e. glass for the production of new PV panels). This process would allow the recycling of antimony used in the glass and currently dispersed in the secondary glass production. In particular, this scenario would allow an overall benefit of 2,274 kg CO2 eq avoided per tonne of recycled PV (20% higher than the FRELP PV waste treatment base case scenario).