Critical material requirements and recycling opportunities for US wind and solar power generation

The deployment of renewable energy generation technologies, driven primarily by concerns over catastrophic climate change, is expected to increase rapidly in the United States. Rapid increases in the deployment of wind and solar energy will translate to increases in critical material requirements, causing concern that demand could outstrip supply, leading to mineral price volatility and potentially slowing the energy transition. This study presents a detailed demand-side model for wind and solar in the United States using dynamic material flow analysis to calculate the requirements for 15 elements: Cr, Zn, Ga, Se, Mo, Ag, Cd, In, Sn, Te, Pr, Nd, Tb, Dy, and Pb. Results show that transitioning to a completely decarbonized US energy system by 2050 could require a five-to-sevenfold increase in critical material flow-into-use compared with business as usual (BAU), with some materials requiring much larger increases. Rare earth elements (REEs) could require 60-300 times greater material flows into the US power sector in 2050 than in 2021, representing 13%-49% of the total global REE supply. Te requirements for reaching net zero by 2050 could exceed current supply, posing challenges for widespread deployment of cadmium-telluride solar. We also investigate several strategies for reducing material requirements, including closed-loop recycling, material intensity reduction, and changing market share of subtechnologies (e.g., using crystalline silicon solar panels instead of cadmium telluride). Although these strategies can significantly reduce critical material requirements by up to 40% on average, aggressive decarbonization will still require a substantial amount of critical material.