Criterion Energy Partners is aiming to be a next-gen energy company. Photo via Getty Images

Sean Marshall and Danny Rehg founded Criterion Energy Partners in 2020 with the hope that geothermal energy could be the cleaner, safer wave of the future. Less than three years later, the team is close to making their plan a reality thanks to a geothermal well that they hope to drill this year.

Entrepreneurship wasn’t always part of the plan for either partner. When Marshall enrolled in the MBA program at Rice University’s Jones School of Business in 2016, he had a successful career at Credit Suisse and had his eye set on a future political career. But then he met classmate Rehg, whose background was in petroleum engineering. Their wives were both attorneys in the Houston district attorney’s office and the couples became fast friends. They also realized that, as Marshall now puts it, Rehg knew how to drill wells and he knew how to make deals.

In the ensuing years, both Rehg and Marshall's careers evolved and, eventually, the pair started looking for other opportunities. That’s when they read an article in Rolling Stone about geothermal energy.

“It was really a place where it really felt like this was something we were put here to do,” says Marshall.

Marshall and Rehg spent the ensuing months “like rats in a dumpster” learning about the players and opportunities in the geothermal industry and built from there. They learned about Pleasant Bayou Power Plant, a 1989 geothermal energy project based in Brazoria County that was backed by the U.S. Department of Energy.

Last summer, Criterion Energy Partners, a member of Greentown Houston, closed on a 10,000-acre lease around the site of Pleasant Bayou.

"We hope by the end of this year we will be generating electrons,” says Marshall.

Though the company has a patented technology that connects wells to the grid, called Criterion Geothermal System, Marshall says that some of the best advice he’s gotten was, “Don’t fall in love with your technology; fall in love with the problem.” The 2021 Texas freeze reminded the founders what that was.

“People were looking for cleaner, lower-emission power sources and [there was] a need for energy resiliency,” says Marshall, explaining that the freeze created an ideal situation for the company, as people began to think more outside the grid.

The year 2022 was a big one for Criterion Energy Partners. Oil and gas powerhouse Patterson-UTI invested in the company, followed by funding from the Department of Energy. The money not only allowed Criterion Energy Partners to lease their land, they are also now paying 12 salaries, including those of the founders. The team offices in The Cannon’s Esperson coworking space.

“Our mission is to make geothermal commercially viable everywhere,” says Marshall. “I still believe in that.”

However, Criterion Energy Partners may be even bigger than proving an alternative energy source. Marshall says that geothermal is the foundation on which they are building “a next-generation energy company.” Criterion Energy Partners could be the more stable basis for a whole new energy system.

Sean Marshall and Danny Rehg founded Criterion Energy Partners in 2020. Photos courtesy

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Houston brain health co. secures $6.5M for rare disease study

neuro funding

Houston-based Goldenrod Therapeutics, part of Fannin Partners' portfolio, has announced the initial close of a $6.5 million series seed preferred stock round.

The round was led by Ataxia Ventures and an affiliate of Fannin, according to a news release.

Goldenrod Therapeutics plans to use the funding to support manufacturing, formulation optimization, IND-enabling studies and a Phase I study of its drug to treat brain inflammation, known as 11h.

The study will consider how 11h, which blocks the enzyme PDE4, could treat Friedreich’s ataxia (FA), a rare genetic disease that affects movement, speech and balance. To date, other PDE4 inhibitors have proven to regulate neuroinflammation and neuronal signaling, but have had adverse gastrointestinal side effects or have not reached enough of the central nervous system, according to Goldenrod.

The company says its 11h is expected to have "broad applicability" with limited emetric side effects.

“Our 11h program is a next-generation, orally bioavailable, brain-penetrant PDE4 inhibitor, where researchers overcame longstanding limitations associated with earlier PDE4 inhibitors," Dr. Dev Chatterjee, CEO of Goldenrod, said in the news release. "We believe this creates the potential for a best-in-class therapy for Friedreich’s Ataxia and a potential foundation for development across multiple neurodegenerative and neuroinflammatory disorders.”

11h was first developed at the University of Nebraska Medical Center (UNeMed). Houston-based Fannin Partners in-licensed the product 2020 and landed SBIR Phase I funding to support its initial development for opioid use disorder soon after.

Goldenrod has also received funding to study 11h's effectiveness for multiple sclerosis, methamphetamine addiction and cocaine addiction.

Goldenrod says it is developing 11h to target a variety of neurological and inflammatory conditions, including Alzheimer's disease, multiple sclerosis, ALS, substance use disorders, Batten disease, pain and traumatic brain injury.

27 Houston companies make Fortune 500 for 2026, led by energy giants

Houston HQs

Editor's note: This article has been updated to correct the number of companies based in the Dallas-Fort Worth area.

Houston is a giant among U.S. hubs for corporate headquarters.

The 2026 Fortune 500 lists 27 companies based in the Houston area, with many energy companies claiming top spots. Houston ties with Chicago for the second-most Fortune 500 headquarters, preceded only by New York City (53). Dallas-Fort Worth is home to 24 Fortune 500 headquarters.

Texas leads the nation for Fortune 500 headquarters (57), with California in the No. 2 spot and New York at No. 3.

“Texas is the undisputed headquarters of headquarters,” Gov. Greg Abbott said in a news release. “The world’s leading businesses invest with confidence in Texas because of our welcoming business climate, predictable regulatory environment, and skilled and growing workforce. People and businesses are choosing Texas because Texas works.”

The 2026 Fortune 500 ranks the largest U.S. corporations based on revenue in fiscal year 2025.

Here’s a rundown of the 27 Fortune 500 companies based in the Houston area.

  • No. 9 ExxonMobil
  • No. 21 Chevron
  • No. 29 Phillips 66
  • No.55 Sysco
  • No. 75 ConocoPhillips
  • No. 89 Enterprise Products Partners
  • No. 103 Plains GP Holdings
  • No. 133 Hewlett Packard Enterprise
  • No. 149 NRG Energy
  • No. 157 Quanta Services
  • No. 164 Baker Hughes
  • No. 173 Occidental Petroleum
  • No. 179 Waste Management
  • No. 201 EOG Resources
  • No. 204 Group 1 Automotive
  • No. 207 Halliburton
  • No. 223 Cheniere Energy
  • No. 236 Corebridge Financial
  • No. 262 Targa Resources
  • No. 266 Kinder Morgan
  • No. 388 Westlake
  • No. 435 CenterPoint Energy
  • No. 438 APA
  • No. 440 Comfort Systems USA
  • No. 455 NOV
  • No. 488 KBR
  • No. 496 Coterra Energy. Oklahoma City, Oklahoma-based Devon Energy and Houston-based Coterra Energy merged in early May, with the combined company retaining the Devon Energy name and the Houston headquarters.

The Greater Houston Partnership notes the Houston area soon will welcome its 28th Fortune 500 company. Expand Energy (formerly Chesapeake Energy), appearing at No. 362 on the 2026 list, says it’s moving its headquarters from Oklahoma City to Spring this year.

As the natural gas producer prepares to relocate to Texas, it’s hunting for a new leader. Nick Dell’Osso stepped down as president and CEO earlier this year. Board Chairman Michael Wichterich is interim president and CEO.

Dell’Osso became president and CEO of Oklahoma City-based Gulfport Energy effective May 28.

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This article first appeared on EnergyCapitalHTX.com.