Solar cell metals and their hosts: A tale of oversupply and undersupply

Several scenarios have been proposed recently for the future electricity generation approaches that include a substantial share of renewable technologies. The proposed increase in the market share of these technologies has led to increasing concern regarding the availability of the metals required for these technologies, as well as for the impacts associated with their production. In this regards, it is of interest that most of the metals that are essential for renewable technologies are coproduced with other metals: indium, germanium, and cadmium with zinc, and tellurium and selenium with copper, for example. An increase in the demand for the companion metals can be met either by increasing the recycling of these metals, the efficiency of their recovery, or their extraction from primary resources, the latter of which will lead to an increase in the production of the host metals with possible implications on their supply and demand. In this paper we develop a "green energy" scenario to investigate these metal-related issues in detail. Among the results of interest are the following: (1) More Se and Te may require mining more copper than can be used, while extracting more arsenic than can conveniently be sequestered; (2) more In and Ge may require mining more zinc than can be used, while extracting more cadmium than can conveniently be sequestered; (3) oversupply mining of copper and zinc will decrease their virgin metal prices, and thereby discourage end of life recycling of those metals; (4) the greenhouse gases produced by mining oversupplies of the host metals zinc and copper will, in some case, exceed the greenhouse gases savings produced by a fossil fuel to solar cell transition; (5) these challenges can be minimized, but probably not avoided, by increasing the recovery rates of Se, Te, In, and Ge from the host metal ores, and by more efficient end of life recycling. (C) 2015 Elsevier Ltd. All rights reserved.