Dear Stockholders,

Today, about 1,400 people work at G1_Dallas manufacturing American energy. These aren’t assembly-line jobs from the 1950s. We’re talking high‑tech, high‑skill work in robotics, precision engineering, materials science, and quality control. Jobs that pay well. Jobs that need problem solvers. Jobs that build careers.

This is advanced American manufacturing. Humans and advanced robotics, working together to keep one of the world’s most modern solar manufacturing facilities operating safely, efficiently, and profitably.

At T1, we build energy.

We’re operating a facility that produces thousands of solar modules daily. Tested, sorted, and packaged, we load them onto trucks for delivery to tomorrow’s solar farms. To power America’s energy future.

We believe the need for these modules has never been clearer. After years of stagnation, we are in a generational time of energy demand growth. According to the Department of Energy (DOE), in 2025, electricity demand in the U.S. rose 2.8% to a record 4,430 terawatthours, and the DOE expects that electricity generation will rise again in 2026 and 2027. We believe solar and storage are the only energy assets that can scale over the next few years to meet this rising demand.

The United States added 53 gigawatts of new generating capacity to our grids in 2025, the largest increase in more than two decades. We believe this is not ambitious enough. We believe we need to build faster. To accelerate American reindustrialization. To power hyperscalers and win the AI race. To bring advanced manufacturing back.

Last year, 79% of new electricity generation added to U.S. grids was solar and storage. This year is shaping up to be no different. According to data from the DOE, for the first three months of 2026, that figure rose to 88%.

We’ve come a long way fast. Solar and storage were only 15% of new electricity generation as recently as 2018.

In Q1 2026, 88% of new electricity generation added to U.S. grids was solar and storage.

Solar and storage offer a winning combination of scalable, reliable, and low-cost power. This is not about tax credits. All sources of energy benefit from a combination of tax credits, favorable accounting treatment, and grandfathered exemptions from construction codes. We are convinced that the U.S. has the people, skills, technology, and capital to deliver the entire solar value chain from raw polysilicon to solar farm in a cost- competitive manner to support a lasting energy solution.

We see that winning combination being recognized by the market in the U.S. and globally for two reasons. The first is cost. Solar is essentially zero-marginal cost electricity generation for decades. Add in capital costs and it is still a very cost-effective solution, according to Rystad Energy, which also reported that battery costs have also fallen remarkably in recent years. Solar delivers abundant, low-cost electricity; batteries store and shift gigawatts, making the combination both affordable and reliable. According to Rystad Energy, solar PV with battery storage has a levelized cost of energy of $68-133/megawatthour compared to U.S. natural gas of $64-125 and large-scale nuclear power of $177-347.

The second is speed. We believe that solar and storage offer one of the fastest, most scalable routes to electricity generation today and for the foreseeable future.

Technology used to govern energy growth. Today, energy governs AI growth.

For decades, advances in oil and gas production relied on breakthroughs in 3D seismic, hydraulic fracturing, combined cycle turbines, and advances in material science for deepwater drilling. Today, energy gatekeeps growth in technology. Without abundant energy, the contest for AI leadership may be lost.

Our mission is to build advanced, domestic solar manufacturing and supply chains in the United States.

In 2025, our first year as T1 Energy, we optimized operations at G1_Dallas, exceeding nameplate capacity. We manufactured 2.79 gigawatts and generated $755.3 million in net sales. Some may see this as a remarkable accomplishment for a new entrant into solar energy. We see it as a good start.

T1 Energy generated $755.3 million in total net sales for 2025.

We are committed to running G1 as safely, profitably, and efficiently as possible, combining a world-class workforce, robotics, and AI to supply abundant energy profitably.

To create a domestic supply of solar cells for our modules, our team began construction of our flagship U.S. solar cell fab, G2_Austin, in December. Construction on the first 2.1 gigawatt phase is progressing according to plan. And I’m happy to report that T1 remains on track to start cell production in the fourth quarter of 2026. When both phases of G2 are completed, bringing total capacity to a planned 5 gigawatts, we expect to support a workforce of up to 1,800 people.

Operating G1. Building G2. These are the building blocks of a company we intend to turn into a cashflow powerhouse. At T1, we are committed to generate value from these world-class assets.

Last year, we laid the foundation to become a new American solar champion. We expect 2026 to be a bridge year to vertical integration and we expect in 2027 to generate an annualized run rate of $375 million to $450 million in adjusted EBITDA once the first phase of G2 is fully ramped.

We believe there is significant commercial desire for an American manufacturer of high efficiency, competitively priced solar modules. Last year, we saw evidence of our thesis. We signed a long-term offtake deal with Treaty Oak Clean Energy for domestic modules with domestic cells—and completed merchant sales to several of the largest utility and developer customers.

While global module pricing remains competitive, we expect domestic content premiums and our roadmap to drive down costs and position us well.

Today, we’re offering what we believe is a new choice to the market. Customers can now purchase advanced solar modules from an American-owned facility in Texas. We offer domestic TOPCon modules that achieve 23% efficiency. Next year, we expect to offer domestic TOPCon modules with domestic TOPCon cells. We believe customers will continue to embrace the combination of high efficiency, low-cost modules that are manufactured in America.

Our guiding focus is investing in American advanced manufacturing to power our nation’s energy independence and bring cutting-edge technology capabilities back to the U.S. Manufacturing our electrons in the U.S. can assist in keeping energy affordable, helping ensures data centers have the scalable energy they need when and where they need it, supporting a U.S. polysilicon industry, and empowering the U.S.’s AI leadership.

We believe domestic solar manufacturing means the U.S. can continue to be the number one exporter of oil and natural gas while ensuring ample affordable power here at home. Last year, the U.S. exported more liquefied natural gas than any other country has, ever. Solar energy can free natural gas for export. America’s energy abundance (lots of both natural gas and solar farms) creates opportunities to keep energy and electricity prices low at home while also helping it continue to be a world-class energy exporter. In the U.S., solar and natural gas are working together to fortress America and keep energy insecurity far from our shores.

Solar is how energy abundance becomes durable and permanent. Manufacturing energy abundance with free sunlight is one way we can unlock the next era of American strength.

Domestic solar energy is energy security and energy security leads to economic prosperity. We are proud to play our our role in securing a bright future for the United States. Thank you for coming along on this journey.

Sincerely,

Daniel Barcelo Chief Executive Officer and Chairman of the Board

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This letter was filed with the SEC on May 18th, 2026. Access the full proxy statement on our Investor Relations page here.