President Donald Trump signed a proclamation on August 6, 2026, imposing new tariffs on imports of polysilicon and certain downstream polysilicon derivatives under Section 232 of the Trade Expansion Act of 1962. The measures take effect for goods entered for consumption on or after 12:01 a.m. ET on December 4, 2026. Raw polysilicon is subject only to the minimum import price-based duty, while downstream derivatives face both the price floor and the 15% ad valorem tariff. The order’s most commercially consequential feature is not the tariff rate itself but a tiered price-floor program that forces every importer of solar wafers, cells, and modules to certify that their product clears a federally set minimum price, or face rejection at the border.
What the price floors require
The minimum import price program sets price floors of $21 per kilogram for polysilicon, $100 per kilogram for ingots and wafers, $0.22 per watt for solar cells, and $0.38 per watt for solar modules.
To comply with the minimum import price program, importers must submit documentation showing either that the first arm’s-length sale of the imported product in the US will occur at or above the applicable minimum import price, or that the sale is covered by a contract with fixed terms signed before August 6, 2026.
Imports of silicon photovoltaic cells and modules were previously subject to a safeguard action under Section 201 of the Trade Act of 1974, under which the United States had imposed tariff-rate quotas from January 2018 to February 2026. The Section 232 proclamation replaces those safeguard measures and broadens coverage, reaching further upstream to include polysilicon, ingots, and wafers, precisely the stages where US domestic capacity is thinnest.
According to the proclamation, the US share of global polysilicon production capacity had fallen from 50 percent in 2005 to under 2 percent in 2024.
Materially inaccurate certifications trigger a permanent import ban, a penalty designed to deter companies from submitting false pricing documentation to clear the price floors.
A supply chain that still skews toward assembly
The proclamation lands against a US solar manufacturing base that has grown dramatically in module assembly but remains thin at earlier production stages. Module manufacturing grew more than 50 percent in 2025, with 65.5 gigawatts of capacity online, up from 42.5 gigawatts at the end of 2024.
SEIA reported that US solar module manufacturing capacity reached approximately 65.5 gigawatts in 2025. Domestic module manufacturers currently rely heavily on imported cells, and the US has only 3 gigawatts of solar cell manufacturing capacity.
That imbalance, which GCN has tracked in cell manufacturing lagging far behind modules, now sits directly in the crosshairs of the wafer and ingot price floor. Because so few wafers are made in the US, virtually every crystalline silicon module assembled domestically still depends on imported wafers to fill its cells, meaning even American-assembled panels are exposed to the new compliance burden.
According to PV Tech Market Research’s latest manufacturing and shipment data, US polysilicon capacity stands at 36 gigawatts, but only 15.5 gigawatts is currently allocated to PV production. That gap exists because US polysilicon capacity is shared with semiconductor-grade production, meaning a significant portion of the ceiling is unavailable to solar from the outset.
Differentiated country rates and the onshoring incentive
The proclamation includes special treatment for covered products originating from Japan, South Korea, Taiwan, Switzerland, Liechtenstein, and European Union member states, for which the combined total of the new Section 232 tariff and the existing column-1 duty rate is capped at 15 percent. For covered products of the United Kingdom, the additional duty will be 10 percent.
Products from countries not on the preferential list, most notably China, the dominant global supplier, face the full rate on top of existing duties.
The new tariffs and minimum import prices are poised to have a significant impact across solar supply chains, from polysilicon producers and cell manufacturers to project developers and engineering, procurement and construction firms sourcing modules for utility-scale and distributed generation projects.
With the December 4, 2026 effective date approaching, industry participants will need to begin evaluating their existing supply agreements and assessing exposure to the MIP certification requirements, and to consider whether the onshoring incentive program may present strategic opportunities.
The proclamation directs the Commerce Department to administer a separate onshoring incentive program, details of which have not yet been published in the Federal Register. Companies considering US manufacturing investments have been advised to monitor forthcoming Commerce guidance regarding that program.
Industry context heading into December
The action is described by industry analysts as one of the more consequential trade moves the US solar industry has seen since the One Big Beautiful Bill was signed into law on July 4, 2025, officially ending the Section 25D federal solar tax credit for homeowners on December 31, 2025. Commercial credits under Section 48E remain available but must meet new construction deadlines and equipment sourcing rules that were not part of the original Inflation Reduction Act.
The $100-per-kilogram floor on ingots and wafers is the threshold analysts flag as most disruptive, because global spot prices for wafers have traded well below that level for much of 2025 and 2026.
The push toward domestic cell production is already visible on the factory floor. In June 2026, Qcells announced that it had begun manufacturing solar cells at its Cartersville, Georgia factory. The Cartersville plant is the first and only US factory to produce the major parts of a solar photovoltaic module under one roof, from ingot to finished panel. Suniva, meanwhile, announced a new US cell factory investment earlier this year.
Whether that buildout can close the gap before December 4, and before importers are forced to certify compliance with prices the market has rarely seen, is the defining question now facing the industry’s procurement desks.
