Material requirements and availability for multi-terawatt deployment of photovoltaics

Abstract

This study investigates growth rates and material flows required to reach and sustain multi-terawatt installed capacity of photovoltaics (PV). The dynamics of material flows over time are captured, taking account for the life expectancy of PV technology. Requirements of solar grade silicon and silver for crystalline silicon (c-Si) technology, as well as indium, gallium, selenium, tellurium, and cadmium for currently commercial thin film (TF) technology are explored, accounting for different technology choices and potential improvements in material intensities. Future availability of these materials from primary resources, as well as secondary resources from end-of-life recycling, is also analyzed. Rapid deployment of c-Si technologies would require a major expansion of solar grade silicon production, and significant quantities of silver. Availability of materials such as indium and tellurium could become problematic for major implementation of TF technology, unless production can be scaled up significantly, or material intensities radically decreased. Availability of secondary resources from end-of-life recycling have little impact on material availability during the growth phase, but could be important for sustaining a low-carbon energy system over longer time perspectives. Material availability could cause problems for rapid PV growth, but does not necessarily limit total PV deployment, especially if material intensities are decreased.