Recycling end-of-life silicon PV panel with molten salt bath

Abstract: Solar energy is recognized as a clean way to produce electricity. Solar PV's installed capacity is increasing in recent years. However, a PV panel has a 25-year lifespan on average. In actuality, 95% of the mass of PV components can be recycled. Recycling of end-of-life PV hence becomes significant. The primary aim of this research endeavor is to propose a recovery methodology for enhancing the thermal treatment of crystalline silicon (c-Si) photovoltaic (PV) panels through the utilization of molten salt immersion. This study seeks to determine the optimal treatment conditions in terms of temperature and duration for this innovative approach, and additionally, to evaluate the economic viability of implementing this recovery technique within an industrial context. The study is structured into distinct phases. Firstly, an in-depth review of existing literature is conducted, focusing on areas encompassing PV recycling, polymer pyrolysis experiments and the utilization of molten salts. Subsequently, the experimental phase is initiated, involving the conceptualization, design, and execution of the experiments. The experimentation comprises two main components: Thermogravimetric Analysis (TGA) testing and PV recycling with molten salt bath experiment. Once the experimental data is acquired and analyzed to identify the optimal temperature and duration, an economic assessment is conducted. The findings from the conducted experiments reveal that the optimal operational conditions entail subjecting the PV panels to a temperature of 430 °C over a duration of 30 minutes with molten salt bath. Following this thermal treatment, the resultant outputs include separated, clean glass, silicon components, and copper ribbons. In conjunction with the experimental outcomes, the economic evaluation is performed. The financial analysis indicates that the proposed recycling of end-of-life PV panels through molten salt immersion yields a net present value (NPV) of 49832.1 Euros, accompanied by a payback period of 6.2 years. Furthermore, the net revenue generated 0.026 Euros per kilogram of processed PV panels. Sensitivity analysis demonstrates that increasing the daily processing weight of PV panels augments the potential profitability. Additionally, as the quantity of adhered salt per panel escalates, both NPV and net recycle revenue experience a decrease. Among the recycled materials, namely aluminum, junction box, copper ribbon, and flat glass, fluctuations in the prices of aluminum and flat glass emerge as the most influential parameters impacting the project's key economic performance indicators. Notably, a rise in the prices of these four materials correlates with a linear increase in NPV and a reduced payback duration.