US signs proclamation imposing solar-supply-chain price floors and a 15% tariff from December 4
The Map Moved · Friday, 11 September 2026
Why it matters
The measure formally shifts leverage toward US-based upstream solar manufacturing while raising the cost and compliance burden for imported inputs. It targets a documented collapse in the US share of global polysilicon production—from about 50% in 2005 to below 2% in 2024—so the immediate effect is to regulate a supply chain that remains heavily import-dependent rather than to close an existing domestic capacity gap.
What happened
President Trump signed Proclamation 11052 on August 6, creating minimum import prices of $21/kg for polysilicon, $100/kg for ingots and wafers, $0.22/W for cells, and $0.38/W for modules. From December 4, downstream products will also face a 15% Section 232 tariff; products from the EU, Japan, South Korea, Taiwan, Switzerland and Liechtenstein generally face a combined duty of 15%, while UK products face a 10% Section 232 tariff. Importers must document compliance, and materially inaccurate certifications can lead to additional duties, penalties and a permanent US import ban; Commerce can waive duties for companies submitting plans to build or expand US facilities.
Previously
Jul 2025 — The US Department of Commerce initiated a Section 232 investigation into imports of polysilicon and derivative products.(US Department of Commerce via gcn.com)
2005–2024 — The US share of global polysilicon production fell from approximately 50% in 2005 to less than 2% in 2024.(US Department of Commerce investigation via gcn.com)
Players & places
- United States
- US Department of Commerce
- US Customs and Border Protection
- Donald Trump