SEG Solar officially inaugurated its second US photovoltaic module manufacturing facility in Tomball, Texas on August 7, 2026, expanding its total US module manufacturing capacity to 6 GW annually. The Houston-based company had separately announced plans on June 1, 2026 for a third factory that would push its domestic footprint to 10.6 GW, a scale its executives say would make it the largest crystalline silicon solar module assembler in the country.
What opened and what was announced
The new facility is a 4 GW solar module assembly plant in Tomball, Texas, with four production lines dedicated to manufacturing SIERRA N series high-efficiency heterojunction (HJT) modules supporting both 210 mm and 210R wafer formats. Commercial operations are expected to begin in the third quarter of 2026. Once the plant is fully operational, it will bring SEG’s annual module assembly capacity to 6 GW, joining the company’s original 2 GW facility in nearby Houston.
On June 1, 2026, SEG Solar announced plans to develop its third US manufacturing facility in Greater Houston, Texas. The newly planned facility is a 1.15 million square-foot building housing a warehouse and module assembly factory with a planned production capacity of 4.6 GW per year. The new facility would be located across the street from the new Tomball plant and bring the company’s total annual capacity to 10.6 GW, making it the largest crystalline silicon solar module assembler in the United States.
In addition to the new module capacity, the company said it plans to build a solar cell manufacturing plant in the US by 2028. That cell plant would represent a move upstream in the supply chain, beyond the module assembly work that currently defines SEG’s domestic operations.
Scale and investment
The second facility represents an investment of $200 million and spans more than 500,000 square feet, making it one of the country’s largest HJT module manufacturing facilities.
As part of its continued US expansion, SEG has signed an agreement with a local construction company to develop the new 4.6 GW third facility on a site spanning approximately 1.15 million square feet, including a factory and a warehouse.
Construction of the third facility is projected to be completed by March 2027, with commercial production expected to begin in May 2027.
By the end of 2025, SEG had shipped over 7.5 GW of solar modules worldwide and reached a module production capacity of 6.5 GW. SEG Solar brought its first 2 GW manufacturing plant into service in August 2024.
Trade backdrop driving localization
SEG is one of a group of US solar companies racing to localize supply chains amid shifting tariffs and trade rules. That race has intensified following a wave of import duties on panels produced in Southeast Asia.
GCN has previously reported that Commerce finalized dumping duties reaching 249.13% on solar cells from India, Indonesia and Laos, and that a federal price floor set at 38 cents per watt locks every solar module importer into a minimum sticker price before any duty is added. Those measures are part of the trade landscape that companies such as SEG are navigating by building domestically.
The third factory is being planned to support SEG’s transition toward next-generation HJT technology, enabling high-efficiency module production aligned with the evolving needs of the US market. HJT cells command a premium over the standard TOPCon and PERC cells that currently dominate volume production. The technology choice signals SEG’s intent to move toward higher-margin products as the domestic market matures.
Houston’s emerging solar cluster
The concentration of capacity in the greater Houston area is creating what industry observers describe as a nascent solar manufacturing cluster in a region long defined by oil and gas.
Developers plan to add 43.4 GW of new utility-scale solar capacity to the US power grid in 2026, a 60% increase in capacity additions from 2025 if realized, according to the US Energy Information Administration. That demand backdrop underpins the business case for every new domestic module factory opening this year. SEG’s official inauguration announcement is available on the company’s press page.
