The United States Geological Survey (USGS) has released the 2025 Critical Minerals List, which includes silicon and tellurium. These two minerals are key raw materials for producing n-type and thin-film cadmium telluride (CdTe) solar modules, respectively.
Silicon is the foundational mineral for most current solar technologies, used to produce polysilicon, which in turn is used to manufacture silicon wafers. According to the USGS report on silicon, there are currently four companies producing polysilicon in the United States.
Silicon and tellurium are essential minerals for manufacturing solar modules.
The report summary cited examples of companies building silicon-based solar supply chains without explicitly naming them, though some clearly pointed to Hanwha Qcells (mentioning its vertically integrated factory in Georgia) and REC Silicon (mentioning its halted production of electronic-grade polysilicon in Montana).
Furthermore, the summary highlighted that nearly 80% of the estimated global production of silicon materials (not limited to solar products) in 2024 originated from China.
Regarding tellurium and its application in CdTe thin-film solar technology, First Solar is the most well-known company using this technology. The company recently announced plans to build another US manufacturing plant next year, expected to reach a nameplate annual capacity of 3.7 GW upon full ramp-up in the first half of 2027.
The USGS Critical Minerals List helps identify minerals vital to the US economy and national security, and whether their supply chains are vulnerable to disruption. In the case of silicon, the majority of solar manufacturing capacity across the supply chain remains concentrated in China, particularly in the wafer segment.
The Solar Energy Manufacturing for America Coalition (SEMA), a trade group for US solar manufacturers, welcomed the addition of silicon and the continued inclusion of tellurium. The coalition had called for silicon’s inclusion and tellurium’s retention last September.
Mike Carr, Executive Director of SEMA, stated: “The United States leads the world in cadmium tellurium technological innovation and manufacturing. This continued recognition will help strengthen the domestic tellurium refining and recycling supply chain, supporting American solar manufacturing and innovation.”
The inclusion of silicon comes just days after the US solar industry celebrated the onshoring of the entire supply chain, with Corning’s ingot and wafer factory scheduled to commence operations in the third quarter of 2025.
Carr added: “Together, these actions signal that the administration recognizes that energy security depends on a strong and resilient supply chain from raw materials to finished solar modules. We look forward to working together to ensure these critical designations translate into meaningful policy tools that reduce supply chain risk, create American jobs, and enhance US energy leadership.”
However, solar manufacturing in the US that uses silicon remains scarce, with the combined annual nameplate capacity for polysilicon and wafer manufacturing insufficient to meet current market demand. Projected market demand for 2025 is less than 50 GW, according to the latest data from the Solar Energy Industries Association (SEIA).
