The White House has set firm numbers for its new solar import restrictions: starting Dec. 4, imported polysilicon enters the U.S. at a minimum of $21 per kilogram, polysilicon ingots and wafers at $100 per kilogram, solar cells at 22 cents per watt, and solar modules at 38 cents per watt. The decision, announced Thursday following a Section 232 investigation under the Trade Expansion Act of 1962, also imposes a 15% ad valorem duty on polysilicon derivatives.

For context on where those floors land: the median U.S. module price currently sits at 27.1 cents per watt, according to Anza Renewables' pricing database, reflecting a mix of domestic and imported product. The new import floor is roughly 40% above that median. Modules assembled in the U.S. from imported materials cost 30 cents per watt today — and the cells feeding them will now carry a 22-cent-per-watt minimum import price. Domestic modules built with domestic cells already command 47 cents per watt. Raymond James cleantech analyst Pavel Molchanov notes the new floor will sit at nearly five times the global benchmark price.

The statute behind the action gives the president broad authority to restrict trade in strategic industries after a Commerce Department investigation — the same mechanism used for the steel and aluminum tariffs that have held up legally. That footing is stronger than the across-the-board tariffs Trump imposed in April 2025, which the Supreme Court ruled he lacked authority to levy.

The supply-chain math explains where the price pressure will concentrate. The U.S. became self-sufficient in module assembly within a few years of the Inflation Reduction Act's 2022 manufacturing incentives combining with earlier tariffs, but progress upstream has been far more modest. As of this summer, the country operates 10.6 gigawatts of cell capacity, according to the Solar Energy Industries Association. Qcells, ES Foundry, Suniva and Silfab are the only domestic cell producers, and tens of gigawatts of annual installations will still need imported cells at the new floor prices.

"The U.S. will remain dependent on importing cells, wafers, ingots, and/or raw polysilicon for the foreseeable future," Molchanov said.

The U.S. lacks capacity to produce polysilicon, ingots and wafers anywhere near current domestic demand — the stages where the cost impact will be most pronounced. A cohort of module assemblers faces a squeeze: their finished product gains protection from foreign modules, but their input costs rise unless cell capacity expands.

The built-versus-announced distinction matters here. Qcells, the Hanwha subsidiary that invested more than $2 billion in a combined ingot, wafer, cell and module plant in Georgia, started rolling cells off the line in June, with ingots and wafers scheduled to enter production later this year. Hanwha's stock surged 17% on the announcement before settling back. First Solar, whose cadmium-telluride thin-film technology bypasses the silicon supply chain entirely, gains a competitive cushion; CEO Mark Widmar called the outcome "one of the most strategically significant trade measures in decades."

The ruling includes an exemption mechanism with its own deadline: companies can escape the tariffs if they secure Commerce Department sign-off on factory construction plans by Jan. 20, 2029. Supporters frame that window as the lever that pulls ingot, wafer and cell capacity toward demand.

The Dec. 4 start date has already drawn fire from the tariffs' own supporters. "It gives importers a window to surge product into the U.S. market before duties take effect, which is precisely the kind of behavior our trade laws are designed to prevent," said Tim Brightbill, a partner at Wiley Rein LLP who has petitioned for solar tariffs for years. "It will be critical that the government rigorously enforce the rules against stockpiling so that importers cannot undermine the remedy before it is even in place."

Because the Section 232 action applies globally, it addresses the transshipment pattern that has undercut earlier remedies. "Every time U.S. cell and module producers seek trade relief, the Chinese companies shift their unfair trade practices to other countries," Brightbill said. "We are hopeful that if this Section 232 action is done right, it could be an important step toward addressing this problem."

The cost side falls on developers building the country's largest source of new electricity generation, at a moment when power bills are already climbing and the administration has removed solar tax credits and obstructed permitting. Recent project groundbreakings show how far the domestic-content pitch has traveled — a large solar-battery plant in Arkansas cited First Solar panels, Nextpower trackers and steel piles from a nearby mill.

What happens next turns on two dates and one enforcement question: whether Customs rigorously polices the pre-Dec. 4 import surge, whether developers absorb module costs that are now structurally higher than the global benchmark, and which companies file qualifying factory plans with Commerce ahead of the January 2029 exemption deadline.