A Silicon learning curve and polysilicon requirements for broad-electrification with photovoltaics by 2050

Abstract

This paper investigates the current and future projected silicon demand for the photovoltaics industry towards broad electrification scenarios with over 60 TW of PV installed by 2050. The current silicon consumption contained in cells/modules is 1510-1900 tonnes/GW. However, this does not account for silicon losses during purification, ingot growth and wafering. The global polysilicon demand by the PV industry in 2020 of 452 kt equates to a silicon consumption of approximately 3150 tonnes/GW, suggesting a current utilization factor of 48-60%. Depending on physical constraints determining the lower limit for future silicon consumption, (eg. 1550 tonnes/GW for 30% tandems made on 100 μm thick wafers, with 50% silicon utilization), the cumulative silicon demand to 2050 could be in the range of 45-123 Mt, with an annual demand of 2-9 Mt in 2050. To reduce the environmental impact of silicon wafers, we must increase efficiencies, use thinner wafers, reduced kerf-loss and explore alternative purification methods with low emissions intensities.