In response to the ongoing debate on climate change and cleaner power technologies several scenarios for the future electricity generation have been recently proposed. All of them include a substantial share of photovoltaic solar technologies. However, these technologies are more material intensive than traditional methods of power generation. There is a growing concern about the availability of critical metals including In, Te, Se, Cd, Ge, and Ga that are required for the large scale implementation of new technologies. These elements are companion metals recovered mainly from copper and zinc ores and bauxite. In this paper possible natural constraints on the use of rare elements resulting from the impact of increasing demand for companion metals on the supply of host metals are examined.