(120b) Dynamic Material Flow Analysis of Crystalline Silicon Solar Cells for Circular Economy Transition

Solar photovoltaics (PV) are the fastest growing renewable energy technology for clean, inexpensive, and sustainable electricity generation. Along with numerous technical roadmaps to improve system cost, performance and reliability, the PV industry should also plan to handle large volumes of silicon panel waste, which is initially estimated to be ~13 million metric tons (MT) by 2050 in the U.S. alone. Understanding the magnitude of material needs and how material flows throughout the PV panel life cycle could change with different design, operational, and end-of-life (EOL) choices will help transition into a circular, resource-conserving economy. Herein, we introduce a computational framework for dynamic material flow analysis (DMFA) based on electricity generation to quantify time-series stocks and flows of bulk PV materials (e.g., solar glass and aluminum frames). We apply this PV DMFA model to evaluate cradle-to-cradle life cycles of utility-scale silicon PV systems in the United States in the years 2000 - 2100. We modeled a range of scenarios to understand how material demands depend on selected PV-related parameters, different material circularity strategies, and recent module design trends (e.g., bifacial or high power). We found that cumulative float glass and aluminum needed for PV installations would likely reach 100 million MT and 12 million MT by 2100, respectively, in the baseline scenario. The most influential parameters for PV installation and subsequent waste reduction include module lifetime, module efficiency, annual degradation rate and material intensity. Ongoing trends to produce larger power frameless modules could save 10 million MT of glass and ~9 million MT of aluminum. Module recycling and component remanufacturing were found to be potentially the most effective material circularity strategies for waste minimization if challenges to their implementation can be overcome. Standardization of module size, minimally intrusive recycling, and careful scrap handling and cleaning could facilitate improved material circularity and reduced waste. The model will be publicly available, and the framework serves as a sustainability support tool for efficient material management of PV energy systems in the circular economy.