Environmental impact of tellurium: From copper mining to thin film solar modules

Cadmium-telluride (CdTe) is the leading thin-film solar technology, holding 21 % of the US market. The demand for tellurium will rise in the US as domestic CdTe production is expected to reach 14 GW by 2027. Over the past decade, the US has begun domestic tellurium production and reduced import reliance from 95 % to less than 25 %. This shift presents an opportunity to minimize the environmental impact of tellurium production. Tellurium is primarily recovered from copper anode slimes via chemical- or heat-based extraction methods. Previous studies use life cycle assessment to evaluate the environmental impact of tellurium. However, these studies model anode slime treatment using electronic scrap processing data as a proxy, which does not accurately reflect commercial processes, and as a result, offers misleading insights for decision-makers. To address this gap, the current study uses life cycle assessment to estimate the environmental footprint of tellurium production via hydro- and hydro-pyrometallurgical processing in China, Canada, Japan, and USA. This work highlights the effect of the tellurium production method and location on the environmental impact of tellurium and CdTe solar modules. The results show that previous estimates underestimate the carbon footprint of semiconductor-grade tellurium by up to 46 %. The literature also underestimates freshwater toxicity and the abiotic depletion potential of CdTe solar modules by 35 % and 50 %, respectively. Finally, producing tellurium via anode slime hydro-pyrometallurgical treatment in the US leads to the lowest environmental impact of US-made CdTe solar modules.