Sweetwater Carbon Storage Hub Completes Deepest Carbon Storage Well in the Nation

EVANSTON, Wyo. and DALLAS, Sept. 2, 2025 /PRNewswire/ -- Frontier Infrastructure Holdings (Frontier), a portfolio company of Tailwater Capital and a leading developer of low-carbon infrastructure across the Mountain West and Texas, today announced a major milestone in its carbon storage development efforts. In partnership with the University of Wyoming's School of Energy Resources (SER), Frontier has successfully completed drilling operations for a second deep characterization well (J1-15) at the Sweetwater Carbon Storage Hub (SCS Hub)—a key step in advancing commercial-scale carbon sequestration in Wyoming.

Reaching a total vertical depth of 18,437 feet, the J1-15 well is now the deepest Class VI carbon storage well ever drilled in the United States. Preliminary data from the well is highly encouraging, showing geologic similarities to a proven acid gas injection site located just over 25 miles north. These results further validate the potential of the SCS Hub as a large-scale, permanent carbon storage facility.

"Successfully drilling and testing a second well on this project has confirmed our preliminary interpretation of the reservoir and is a major step forward to validate the region's storage potential," said Robby Rockey, President and Co-CEO of Frontier. "This deeper well gives us a more complete picture of the subsurface, reinforcing our commitment to building scalable, practical carbon solutions for Wyoming's key industries."

The SCS Hub is part of the U.S. Department of Energy's CarbonSAFE Initiative and is co-led by SER and Frontier. The project aims to establish a commercial-scale carbon capture, utilization, and storage (CCUS) hub in Sweetwater County, capable of delivering long-term, secure CO₂ storage for industrial emitters across the region.

The J1-15 well was initially drilled to access the Nugget Sandstone formation, yielding 147 feet of core. After successfully drilling the project's first well (SCS-1), the team then extended J1-15 to reach the Madison Limestone, another high-priority formation. This dual-target strategy is central to understanding the full storage capacity of the hub. Geological evaluation is being led by SER's Center for Economic Geology Research (CEGR). The team has collected core samples, well logs, and water from the site, which will undergo detailed analysis to assess reservoir characteristics and seal integrity.

"Securing Class VI permits and executing a drilling program to this depth required meticulous planning and coordination with multiple regulatory bodies," said Alicia Summers, Frontier's Chief Development Officer. "The geological data we're seeing reinforces why we selected this location and validates our technical approach to developing world-class carbon storage infrastructure."

The technical results support this strategic approach. "The decision to deepen the well to the Madison Limestone has proven successful," said Zunsheng "John" Jiao, Program Manager at CEGR and Co-Principal Investigator of the project. "The logging data confirms a continuous zone of strong porosity and flow—indicators of excellent storage potential."

The project team is particularly optimistic about the Madison Limestone, a formation also utilized in North America's largest CCUS operation located 25 miles to the North of the SCS Hub. The analog underscores the Madison's promise as a safe and effective storage reservoir.

"We've seen what the Madison can deliver through Shute Creek," added Rockey. "Now we're applying those learnings here, with results that are very promising."

In tandem with fieldwork, the SCS Hub continues to progress toward key regulatory and engineering milestones. The next phase will focus on detailed modeling, permitting, and preparation for eventual injection operations.

"I'm proud of our team and partners for reaching this critical point," said Fred McLaughlin, Director of CEGR. "The data collected from this well is essential to confirming the feasibility of the SCS Hub and advancing Wyoming's position in the emerging carbon economy."

About Frontier Infrastructure Holdings
Frontier Infrastructure Holdings, LLC is a leading developer of low-carbon infrastructure solutions across the Mountain West and Texas, specializing in integrated power generation and carbon capture and storage projects. The company is at the forefront of industrial decarbonization, providing scalable, permanent carbon storage and behind-the-meter power solutions to support growing regional energy demand. For more information, please visit www.frontierccus.com.

About the University of Wyoming's School of Energy Resources
The School of Energy Resources (SER) at the University of Wyoming collaborates with state, national, and international stakeholders to advance energy technologies and policies to grow and support Wyoming's robust energy sector. SER's mission is to advance energy-driven economic development for the state of Wyoming. It leads the University of Wyoming's talent and resources for interdisciplinary research and outreach, fulfilling Wyoming's promise to be a global leader in a thriving and sustainable energy future. For more information, please visit www.uwyo.edu/ser.

About Tailwater Capital
Dallas-based Tailwater Capital is an energy infrastructure private equity firm with a well-established track record of working constructively with proven management teams to deliver value-added solutions. Tailwater has raised more than $5 billion in committed capital since inception and the team has executed more than 285 transactions representing over $27 billion in value. For more information, please visit www.tailwatercapital.com.

Frontier Media Relations
Jill McMillan
Managing Director, Communications & Public Affairs
+1 214-489-7047
[email protected] 

John Schaufele
Managing Director, Investor Relations & Fundraising
Phone: 214-489-7043
Email: [email protected] 

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SOURCE Frontier Infrastructure Holdings