Recent actions by the US Department of Commerce (Commerce) signal growing trade enforcement momentum across critical segments of the clean energy supply chain. Through a combination of new investigations and preliminary determinations, the agency is expanding its scrutiny of imported materials such as polysilicon, solar modules, and battery components—all central to US decarbonization and domestic manufacturing goals.
Section 232 Investigation into Polysilicon and Derivatives
On July 1, 2025, Commerce launched a national security investigation under Section 232 of the Trade Expansion Act into US imports of polysilicon and its derivatives. Polysilicon is a foundational input for both solar photovoltaics and semiconductors. The agency published a Notice of Request for Public Comment in the Federal Register on July 16, 2025, with a 21-day comment window extending through August 6, 2025.
Commerce seeks input on a wide range of topics, including the current and projected demand for polysilicon, the role of foreign subsidies, the risk of overconcentration in foreign supply chains, and the potential for future export restrictions. Of particular note is Commerce’s focus on the feasibility of expanding domestic capacity and whether additional trade measures—such as tariffs or quotas—are necessary to mitigate import-related national security risks. The investigation must conclude within 270 days, or by March 28, 2026, although the US administration has indicated an intent to expedite such proceedings.
Initial remedies imposed pursuant to Section 232 are made on a prospective basis, meaning from the effective date of the announcement of the remedy. Based on existing Section 232 tariff measures on steel, aluminum, copper, automobiles, and auto parts, we can expect that any new tariff measures will apply on a global basis, regardless of the country of origin for imported merchandise. It is unclear whether alternative remedies—for instance, absolute or tariff rate quotas—might be imposed on particular trading partners. It is also unclear whether any tariff rate would apply only to the value of the polysilicon content of a derivative article or to the full value of a derivative.
Commerce will not reach out to potentially affected parties to request any specific information, so interested parties are strongly encouraged to voluntarily submit comments reflecting the anticipated impact of new tariffs or import quotas pursuant to this investigation.
Petitions Filed Against Solar Imports from India, Laos, and Indonesia
In a separate action, the Alliance for American Solar Manufacturing and Trade—comprising First Solar, Qcells, and Mission Solar Energy, among others—filed new petitions on July 17, 2025, requesting antidumping and countervailing duty investigations into solar module imports from India, Laos, and Indonesia. The petitions allege dumping margins as high as 249.09% and assert that subsidized imports from these countries are harming the US solar manufacturing base.
According to the statutory timeline for antidumping duty investigations, Commerce has 20 days from the date of filing to determine whether it will initiate an investigation. If the investigation proceeds, it would represent another step in the ongoing effort by US manufacturers to address alleged unfair trade practices by Chinese-affiliated producers operating through third countries. Looking ahead, an affirmative decision by Commerce and an affirmative determination of possible domestic injury by the US International Trade Commission could lead to a full investigation timeline extending several months, potentially resulting in new duties on imports from the named countries. If we see an influx of imports of solar cells and modules from Laos, India, and Indonesia during that initial investigation period, it is possible that duties may be applied retroactively to such imports based on a finding of critical circumstances.
Preliminary Duties on Chinese Graphite Anode Material
Separately, Commerce has issued an affirmative preliminary determination in its ongoing antidumping investigation into active anode material from China. This graphite-based input is critical for lithium-ion battery production and energy storage technologies. The agency assigned a China-wide dumping margin of 93.50% and imposed a concurrent 11.58% preliminary countervailing duty.
The scope of the investigation is broad, covering various forms of anode-grade graphite, whether imported directly or incorporated into downstream products such as anode slurries and battery subassemblies. These preliminary duties apply only to the value of the graphite component of the imported product, not the total value of imported merchandise. The investigation now proceeds to the final determination phase, with a conclusion expected by September 29, 2025. It remains likely that incorporated anode material will continue to be within scope, potentially impacting imports of batteries and related systems.
Looking Ahead
These actions demonstrate the federal government’s heightened use of trade policy to secure domestic control over strategic materials essential for solar and battery technologies. Developers, manufacturers, and clean energy investors should closely monitor these proceedings, particularly given the compressed timelines and potential for retroactive duties. Stakeholders with exposure to polysilicon, solar modules, or battery-grade graphite should consider participating in comment opportunities and evaluating supply chain vulnerabilities in light of ongoing enforcement developments.