Future recycling flows of tellurium from cadmium telluride photovoltaic waste

Abstract

According to the European Photovoltaic Industry Association, photovoltaic energy has the potential to contribute up to 13% to the global electricity supply by 2040. A part of this electricity production will come from thin-film photovoltaic technologies. From various thin-film technologies available on the market today, low-cost cadmium telluride photovoltaics (CdTe-PV) can be considered the market leader with a market share of 5% at annual production. There are however two major concerns about this technology: first, the potential negative environmental impacts of cadmium contamination from CdTe-PV; and second, the possible shortage of the metal tellurium in the future. Because of these concerns, the recycling of production scrap and end-of-life PV modules is essential. In this paper we estimate how much tellurium will be recovered from PV scrap to substitute for primary tellurium. In order to estimate global tellurium flows until 2040, we have created a dynamic material flow model for the life-cycle of CdTe-PV modules. Three scenarios, which describe different market developments and technology trajectories, show how material efficiency measures – higher material utilization in production, decrease of material content in PV modules, and recycling of production scrap and end-of-life modules – will affect demand, waste flows, and recycling flows of semiconductor grade tellurium. The results depict that efficiency measures at process and cell level will reduce the specific tellurium demand per watt peak such that total tellurium demand starts to decline after 2020 despite further market growth. Thus, the CdTe-PV industry has the potential to fully rely on tellurium from recycled end-of-life modules by 2038. However, in order to achieve this goal, material efficiency must be substantially improved and efficient collection and recycling systems have to be built up.