President Donald Trump signed a proclamation on August 6, 2026, imposing a 15% ad valorem tariff and minimum import prices on polysilicon and its derivatives under Section 232 of the Trade Expansion Act of 1962, effective December 4, 2026. The minimum import price program sets price floors across the supply chain, while the 15% ad valorem tariff applies to downstream derivative products, not to raw polysilicon itself, to incentivize onshoring of value-added processing. The action, grounded in national security law, marks a significant expansion of federal trade intervention across the solar supply chain.
What the proclamation does
The proclamation was signed on August 6, 2026, following the Secretary of Commerce’s finding that such imports threaten to impair U.S. national security under Section 232 of the Trade Expansion Act of 1962. According to the accompanying White House fact sheet, the proclamation aims to strengthen U.S. supply chains, support domestic polysilicon production, and address national security concerns related to imports. The order establishes a minimum import price program on imports of polysilicon and polysilicon derivatives to create a level playing field for American producers, and imposes a 15% ad valorem tariff on derivative products that are downstream of polysilicon to encourage onshoring.
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 U.S. 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.
The proclamation provides differentiated country treatment: for covered products of the United Kingdom, the additional duty will be 10%. The proclamation includes special treatment for covered products originating from Japan, South Korea, Taiwan, Switzerland, Liechtenstein, and European Union member states, for which the additional Section 232 tariff and the applicable HTSUS Column 1 duty rate will generally equal a combined rate of 15%.
Why the administration acted now
The United States’ share of global polysilicon production capacity has fallen from 50 percent in 2005 to less than 2 percent in 2024.
Polysilicon is a critical input for semiconductor and solar product manufacturing, supporting virtually every sector of the modern economy, including defense, cybersecurity, communications, artificial intelligence, renewable energy, and advanced manufacturing.
The new measures replace the expired solar safeguard tariff under Section 201 of the Trade Act of 1974 that lapsed in February 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 new action expands coverage to the full polysilicon supply chain.
Industry analysts noted the breadth of the change. The new rules were described as “one of the biggest events in the US solar landscape” by Moustafa Ramadan, head of market research at PV Tech Research. “It will change how module procurement works in the US entirely,” he added.
Onshoring incentives built into the order
The proclamation authorizes the Secretary of Commerce to establish an incentive program for companies that will invest in building, expanding, or refurbishing facilities that produce polysilicon and polysilicon derivatives.
A company with an approved plan may be permitted to import necessary production equipment and covered products without paying applicable Section 232 duties, in volumes the Secretary considers commensurate with the company’s newly committed investment. The benefits will be tied to the facility’s construction period, contingent on sufficient progress under the approved plan and subject to monitoring and enforcement.
T1 Energy operates a 5GW solar module facility in Dallas, Texas, and has a 2.1GW solar cell fab, G2_Austin, under construction. Dan Barcelo, Chairman and CEO of T1 Energy, said the proclamation is “a win for advanced American manufacturing and investment in domestic energy supply chains,” adding that it “helps companies like ours that are creating thousands of high-quality American jobs.”
The onshoring carve-out is likely to accelerate existing factory plans. Domestic solar manufacturers have been expanding rapidly, with several multi-gigawatt assembly facilities already under construction across Texas and the Southeast, and upstream supply chain gaps remaining the sector’s most acute constraint heading into late 2026.
What comes next for solar buyers and developers
With a four-month window between the August 6 signing and the December 4 enforcement date, importers have strong incentive to accelerate procurement. That dynamic could create a temporary increase in panel supply in the U.S. market, followed by a price adjustment once the tariffs take effect.
Many U.S. factories still depend on imported wafers and solar cells, meaning the minimum price floors could ripple through project budgets even for domestically assembled modules.
The procurement calculus has already grown more complex since January 1, 2026, when Foreign Entity of Concern rules took effect, splitting the commercial solar market into two tiers. Panels with FEOC-compliant, domestically sourced supply chains command a premium and unlock the additional Domestic Content Bonus credit, while non-compliant panels are cheaper but ineligible for the bonus.
The Section 232 action layers a hard price floor and an additional duty on top of that existing incentive structure, further pressuring project developers to lock in supply agreements before December. Those cost pressures sit alongside broader rate concerns already reshaping power bills; residential electricity costs have climbed nearly 40% since 2021, making the downstream pricing implications of any supply-chain shock politically sensitive as well as financially significant.
The White House published a fact sheet on the proclamation on August 6. The measures take effect at 12:01 a.m. Eastern Time on December 4, 2026, giving the Commerce Department roughly four months to stand up the minimum import price certification system and begin reviewing company onshoring plans.
