Abstract Of the materials of current research interest in thin-film photovoltaics, Ru and Te are amongst the nine rarest elements in the earth's crust, with In and Se in positions 11 and 14, raising the issue as to what constraints, if any, are placed on future thin-film photovoltaic manufacturing volumes by such scarcity. Te provides an interesting case study since more than 600 t has been incorporated into CdTe modules fielded to-date, with CdTe technology recently consolidating its position as the most successful commercial thin-film technology. The origin and impacts of recent fluctuating Te market conditions are discussed as are new insights into long-term supply from Cu refining.