Life cycle inventory analysis of the production of metals used in photovoltaics

Material flows and emissions in all the stages of production of zinc, copper, aluminum, cadmium, indium, germanium, gallium, selenium, tellurium, and molybdenum were investigated. These metals are used selectively in the manufacture of solar cells, and emission and energy factors in their production are used in the life cycle analysis (LCA) of photovoltaics. Significant changes have occurred in the production and associated emissions for these metals over the last 10 years, which are not described in the LCA databases. Furthermore, emission and energy factors for several of the by-products of the base metal production were lacking. This review article aims in updating the life cycle inventories associated with the production of the base metals (Zn, Cu), and defining the production paths and emission and energy allocations for the minor metals (Cd, Ge, In, Mo, Se, and Te) used in photovoltaics.