The United States has built barely 3% of the domestic solar cell capacity needed to feed its TOPCon module assembly lines, creating the widest technology mismatch in the nation's photovoltaic manufacturing sector, according to a new analysis from PV Tech Research published this week. The report finds that American manufacturers are hedging against patent litigation by spreading investment across three competing crystalline silicon technologies—PERC, TOPCon, and HJT—rather than converging on the single dominant standard that has taken hold globally. This legal strategy, not technical or cost logic, is reshaping the entire supply chain and locking in capacity gaps that will persist through 2030.

TOPCon module capacity has reached 32.7GW against 22.2GW of actual output, a utilisation rate of 68%, but domestic cell capacity stands at only 1GW with production of just 311MW—a 31% utilisation rate that represents the weakest cell-stage performance of any crystalline technology tracked. PERC module capacity sits at 24.8GW versus 15.4GW of production, while PERC cell capacity covers merely 30% of module needs at 7.5GW capacity and 4.6GW output. HJT follows a similar pattern on a smaller scale: module capacity of 5.5GW against 2.4GW of production, with cell capacity of 2.1GW covering roughly 38% of module requirements. Across all three technologies, domestic cell production falls far short of what's needed to supply US module assembly, forcing reliance on imported cells—particularly for PERC and TOPCon modules, where more than half the silicon must come from abroad.

The report states that this technology diversification functions as a hedge against legal risk, with patent litigation shadowing the industry's typical migration from PERC to TOPCon and onward to back-contact designs at each transition point. The analysis finds that a significant share of US manufacturers have bypassed the conventional TOPCon-to-back-contact path entirely, instead committing to HJT as an alternative route or sticking with PERC rather than following the upgrade trajectory standard in other markets. Looking at the pipeline of projects under construction, the report notes TOPCon leads newly announced cell capacity at 13.1GW, HJT at 12.16GW, and PERC at 11.8GW, but at the module stage HJT dominates with 16.56GW of announced capacity compared to just 1GW for TOPCon and 4GW for PERC.

That divergence reveals manufacturers willing to build TOPCon cell lines because it's the most commercially proven technology with clear efficiency gains over PERC, but concentrating new module capacity around HJT—a signal they view it as further removed from the patent risks accumulating around the TOPCon-to-back-contact shift. The report explains this creates a structural feature of the US solar landscape shaped as much by legal strategy as technical merit, with the cell-to-module gap set to persist across all three technologies regardless of which one ultimately wins out. The analysis warns this isn't a temporary phase but a defining characteristic that raises questions about whether a multi-technology approach can hold up as capacity scales and competitive pressure mounts. The final article in the series will project where US solar manufacturing capacity is headed by 2030 across each production stage and technology, and what those forecasts mean for manufacturers, policymakers, and the market dynamics shaping the next wave of this buildout.