J
jeremy
3 minutes
Tellurium Supply for Thin-Film Solar: A By-Product of Copper Refining
Tellurium supply for thin-film solar sets a ceiling on how far CdTe panels can grow. Tellurium is one of the rarest elements in Earth's crust. It is almost never mined on its own. Most of it comes from anode slime, the sludge left in the tanks when copper is refined by electrolysis. Because it is a by-product, its supply follows copper output, not solar demand. A jump in panel orders cannot quickly raise tellurium output. Getting tellurium out of the slime takes roasting and acid leaching, which add their own fumes and wastewater. Since it rides on copper mining, part of that mine's impact is shared with solar in a life-cycle report. Makers stretch the supply in three ways. They make the CdTe film thinner, they waste less during deposition, and they recover tellurium from old panels. The same by-product problem hits indium and gallium in CIGS cells. When you read that thin-film solar could replace all silicon, check the metal supply first. After this Concept you can explain why tellurium limits CdTe growth and how thinner films and recycling ease it.