Texas-based solar module manufacturer SEG Solar has announced its third domestic manufacturing facility, a 100,000 m2 building housing a warehouse and module assembly factory with a planned production capacity of 4.6 GW per year.

The newly-planned facility would expand the company’s total annual domestic module capacity to 10.6 GW, supported by its n-type cell factory in Indonesia and its upcoming silicon ingot and wafer facility.

Construction on the newly-announced facility is expected to be completed by March 2027, with commercial production beginning two months later.

The latest announcement comes less than one month after the SEG announced its second U.S. site, a 4 GW factory near the company’s Houston, Texas headquarters, for which it plans a grand opening on August 7, 2026.

In addition to the two recently-announced module assembly facilities, the company says it is also evaluating potential U.S. sites for a dedicated heterojunction (HJT) cell manufacturing facility.

SEG’s continued expansion is part of a broader domestic solar module manufacturing trend, with up to 15 GW in total manufacturing capacity expected in Texas in 2026. In fact, the Lone Star state is listed as number one for GDP from clean energy manufacturing, largely due to 30 existing facilities responsible for over $4.2 billion in total GDP, according to a recent report from the American Clean Power Association.

The practicalities of this rapid growth will be a key topic of discussion at the Solar Manufacturing USA conference, presented by pv magazine USA in partnership with Finlay Colville, which takes place on September 22 and 23, 2026 in Austin, Texas.

While many of SEG’s commercially-available products use either the n-Type TOPCon cells it manufactures in Indonesia or PERC cells, the company announced the 740W SIERRA N module, its first module using HJT cells, at RE+ 2025. 

At the time, the company said the new bifacial module made using large-format 210x105mm HJT cells would offer up to 23.82% efficiency, a temperature coefficient of –0.24%/°C, and exhibit an annual degradation of less than 1% in the first year and under 0.3% each year thereafter. 

The company has not announced a date for the commercial availability of the SIERRA N modules.