Environmental impacts of recycling crystalline silicon (c-SI) and cadmium telluride (CDTE) solar panels

Sci Total Environ. 2020 Sep 15;735:138827. doi: 10.1016/j.scitotenv.2020.138827. Epub 2020 May 11.

Abstract

There has been a substantial growth in the deployment of solar photovoltaic (PV) panels in the past couple decades. Solar PVs have a life span of about 25 years and much of the deployed PVs will soon reach their end of life (EoL). It is now timely to plan for the EoL of PVs to recover valuable materials and recycle PV modules sustainably. The goal of this study was to analyze the environmental impacts of different recycling methods for crystalline silicon (c-Si) and CdTe panels. A life cycle assessment (LCA) was performed for delamination and material separation phases of recycling solar panels. The LCA results showed that the recycling of c-Si and CdTe PVs contribute 13-25% and 3-4%, respectively to the entire PV lifecycle impacts. Also, for both c-Si and CdTe PVs, the thermal-based recycling methods resulted in lower environmental impacts than chemical and mechanical methods, except for pyrolysis. Nitric acid dissolution used for c-Si PV recycling had the highest impacts among all methods since the material consumption for this method has not been optimized for industrial use. Results from this study suggested that current techniques used in recycling of PVs, produce higher impacts than extraction of Al, Si and glass for c-Si and extraction of glass for CdTe. Lastly, this study identified which materials to prioritize for highest economic and environmentals benefits from recycling. These will be Ag, Al, Si, and glass in c-Si modules, and Te, Cu, and glass in CdTe modules.

Keywords: Delamination; Life cycle assessment; Material separation; PV end of life; Photovoltaic recycling.