Recyclability Challenges in “abundant” Material-based Technologies

Much current research in photovoltaic technology is directed towards using “abundant” base metals like copper and zinc (e.g., CZTS or more recently CZTSSe) to overcome the the challenges of material scarcity posed by the use of tellurium, indium, germanium, and gallium in current generation products (e.g., CdTe, CIGS, aSi/thin-film Si). The supply of these materials is limited because they are minor byproducts of the production of copper, zinc, lead. and aluminum, so that their economic production inherently is linked to that of the base metals. But, although the base metals currently are abundant, their reserves are not inexhaustible. In addition to concerns on resource availability, the main sustainability metrics for large-scale PV growth are low cost and minimum environmental impact. As the numbers of photovoltaic installations grow, greatly displacing traditional powergeneration infrastructures, recycling will play an increasingly important role in managing their end-of-life fate, so relieving pressure on the prices of critical materials. Identifying the potential issues in current technologies can help implement a take-backor recycling-program ahead of time. Our work explores the potential for material recycling of various established commercial photovoltaic technologies, along with those under development. It sheds light on a dimension of sustainability that has not been investigated before. Based on entropy analyses, documented by the experience of recycling electronic products, we show that recycling some types of PV modules based on “abundant” materials could be burdened by complexity and lack of value, thereby creating concerns about end-of-life environmental impacts, and resource availability.