Looking back on 2025, three companies made headlines for their efforts, and failures, to produce polysilicon in the US. Now, with supply constraints and restrictive legislation looming in 2026 and beyond, polysilicon is emerging as a real choke point for US solar supply.
New solar supply chains are built backwards. Module producers come first, as they need to sell to developers, which is a straightforward pitch. Once you have module production, cell manufacturers can have some assurance of selling their product, and they set up shop, a little slower and at greater expense than the module companies.
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So it continues up the supply chain through silicon wafer slicing, ingot pulling and polysilicon production, getting more intensive and expensive as it goes. In 2025, we saw the green shoots of new US polysilicon production, though it’s unlikely to be plain sailing.
REC Silicon
The year started with bad news for the US polysilicon sector. REC Silicon, the Norway-headquartered firm with two bases in the US, abandoned polysilicon production at its Moses Lake facility in Washington. The decision was apparently due to failing purity tests for its product, which threw its supply deal with Korean-owned solar manufacturer Hanwha Qcells into question.
This decision has since been questioned and triggered a tense battle between minority shareholders in the company and Hanwha—the same company that owns Qcells and has a significant stake in REC Silicon. Some polysilicon industry experts also announced You can read PV Tech’s coverage of the fallout of the Moses Lake closure here.
The shutdown did come as a significant blow to the US solar industry, as Moses Lake was the only operational facility producing solar-grade polysilicon in the US at the time. It produced its polysilicon using the fluidised bed reactor (FBR) method, an alternative to the industry standard Siemens process, and a deal with Qcells for its planned wafer and cell production in the state of Georgia would have marked a significant moment in onshoring the US solar supply chain.
Since REC abandoned solar-grade polysilicon production, the Trump administration has come into office and turbocharged the US’ already quite protectionist trade policies. Of biggest concern is the Section 232 polysilicon tariff, which is currently investigating polysilicon imports from overseas producers into the US to assess their impact on national security and industries. Industry analysts have said that Section 232 could be the biggest “vulnerability” in the US solar supply chain.
REC’s shutdown was likely due to issues with the company itself and its relationship with Hanwha, rather than a bad omen for the prospects of a US polysilicon industry. But it shows the vulnerability at the foundation of the US solar supply chain, as barriers like Section 232 and the upcoming Foreign Entity of Concern (FEOC) laws threaten to raise prices and squeeze supply for the essential raw materials needed for solar manufacturing.
If Moses Lake were operational now, it would be a valuable—if limited—source of domestic polysilicon for Qcells, which is the only company slated to be producing silicon wafers besides Corning, and could have been a beacon for the industry.
But other companies have had more success.
Highland Materials
In 2024, there was a lot of buzz about Highland Materials, the Tennessee firm with plans for 20,000MT of US polysilicon production capacity, which was touted as a “game changer” for the industry.
The company secured US$255 million in tax credits to back its plans for a polysilicon plant and has since announced the lease of a former nuclear site to host the facility. It says it will begin construction on the polysilicon plant in the second half of 2026.
The company is fairly unproven so far, and opinions on it are split. Its plans are ambitious, building out polysilicon capacity at a time when the industry is oversupplied and prices are incredibly low, as well as being the first announcement of a greenfield polysilicon site outside China in years. Some have said it shows the potential of polysilicon production in the US, while others have questioned the wisdom of such ambition in an industry where the legacy Western firms—Germany’s Wacker and US-based Hemlock—have not expanded capacity in a decade.
But things might be changing. The US market could benefit from domestic polysilicon supply if the Section 232 and FEOC rulings are particularly strict, and over in China the sector is being brought into line by Beijing after “cutthroat” competition and overproduction has pushed companies to the brink. On the other hand, we have seen Chinese companies building out capacity in other parts of the world to diversify their operations, which creates more competition and pressure on domestic producers.
Richard Rast, the head of Highland Materials, told PV Tech Premium earlier this year that the company wants to set itself apart with technology. He said a preparatory new technology could bring the innovations needed to compete with China on polysilicon production, where the overwhelming majority of the global supply is produced. Those innovations include recycling kerf—the waste from polysilicon cutting—and reducing production costs and capital expenditure compared with the Siemens process, which is notoriously energy-intensive and pricey.
There are some questions still to be answered, notably about the purity of products made from material including recycled kerf, when advanced solar cells need very high-purity polysilicon to function. But the company seems set on its course, and could prove to be the shot in the arm the US sector needs.
Corning and Hemlock Semiconductor
Chemical giant Corning and its subsidiary Hemlock Semiconductor are building hyper-pure polysilicon and silicon wafer plants in the US. The company began producing wafers earlier this year, at a site in Michigan where it also has a captive polysilicon supply.
“With a collocated polysilicon source on our Michigan campus, our logistics are measured in minutes, not months, making us resilient to trade disruptions,” Corning’s division vice president and commercial director for solar, Phil Rausch, told PV Tech Premium in November.
This operation is the most successful US wafer and polysilicon production project today, and could pave the way for more capacity to come online in the future. While most of the solar cell manufacturers which are due to come online next year will still need to use imported wafers, as Corning is estimated to have only around 2.5GW of annual nameplate production capacity, the impact is still significant.
Corning has deals in place with T1 Energy, a solar module and cell producer that bought Chinese manufacturer TrinaSolar’s assets when it left the US last year, and Canadian module manufacturer Heliene and cell producer Suniva. Should they come off, these deals will mean fully US-made solar modules on the market.
Big players like Corning could lead the sector with their institutional and financial muscle able to manage the cost and long investment times of polysilicon production. For firms big enough to manage the risk, the Trump administration’s penchant for tariffs and trade restrictions could ultimately make the case for US polysilicon production, as established cell and module manufacturers may well see the upside in a more secure, long-term, US-labelled supply chain even at a higher price tag.
