Cleaning Up Clean Energy: Sustainable End-of-Life Practices for Photovoltaics

Abstract

As the first generation of large-scale solar installations begins to reach the end of their 25-year lifespan and solar power becomes more prevalent, solar waste is becoming an increasingly pressing global issue. Solar panels are difficult to disassemble and often end up in landfills, where they leach toxic metal compounds into the environment after disposal. Solar panel recycling can help ameliorate these environmental impacts, but existing recycling techniques often employ harmful chemicals or thermal treatments, which produce undesirable byproducts. This project aims to address environmental concerns associated with ethylene vinyl acetate (EVA) removal, one of the most challenging aspects of solar cell recycling. EVA is an adhesive polymer that joins the glass, silicon solar cell, and backsheet layers together. In this work, we investigate the effect that five chemical alternatives to toluene have on EVA. Gasification and pyrolysis are also explored as an alternative to chemical dissolution methods. Mass loss data and qualitative observations of post-treatment indicate that the chosen solvents can effectively aid in panel disassembly, with some demonstrating results similar to toluene. This project identifies multiple solvents that are promising candidates for the chemical treatment of solar cells for recycling purposes, whose environmental impacts are lower than those currently used in industry. However, the findings also underscore the difficulty of developing a solar panel recycling process free from harmful chemical waste and demonstrate the need to design panels with recycling in mind, especially through the use of alternative encapsulant and backsheet materials.