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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This article originally ran on InnovationMap.

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Electric truck charging network expands to Houston-Dallas freight corridor

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Greenlane Infrastructure, an electric public charging station developer and operator, is expanding outside of its home state of California and into Texas.

The Santa Monica-based company plans to launch its high-power charging sites along the Dallas–Houston I-45 corridor, which is one of the highest-volume commercial trucking routes in the country, according to a news release from Greenlane.

The sites will feature 6-8 pull-through lanes with chargers supporting combined charging system (CCS) and megawatt charging system (MCS) connectors that allow electric truck drivers to recharge their vehicles during standard rest periods. They will also offer tractor parking and charging, as well as operations that will allow for overnight stops.

Drivers can reserve chargers in advance, monitor charging activity in real time, and manage billing from the Greenlane Edge platform.

“Our customers are making commitments to electrify their fleets, and they need a charging network that can grow alongside them,” Patrick Macdonald-King, CEO of Greenlane, said in the release. “This is the first leg of the Texas triangle, one of the more important freight arteries in the country, so bringing high-power charging there is the next logical step in building a network that serves how freight moves across America.”

Greenlane is also expanding across the West Coast, with five locations under development in California and Nevada. It opened its flagship Greenlane Center in Colton, California, in April 2025. The company plans to open locations in Blythe, California, and Port of Long Beach this year.

Greelane was founded in 2023 as a joint venture between Daimler Truck North America, NextEra Energy Resources and BlackRock. It has secured partnerships with electric long-haul truck developer Windrose Technology, Velocity Truck Centers and Volvo Trucks North America.

Houston startup lands $1B from Blackstone and Halliburton, plans acquisition

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Houston-based power generation startup VoltaGrid has nailed down a $1 billion equity investment from asset management heavyweight Blackstone and Houston-based oilfield services provider Halliburton.

The investment comes in two forms:

  • A $775 million primary capital raise
  • A $225 million secondary capital purchase from existing investors

VoltaGrid, founded in 2020, provides behind-the-meter mobile power generation equipment for data centers, microgrids and industrial customers.

Aside from the $1 billion investment, VoltaGrid has agreed to buy Propell Energy Technology, a VoltaGrid supplier, for an undisclosed amount. Propell offers a natural gas power generation platform for AI data centers. VoltaGrid plans to add two manufacturing plants at Propell’s facilities in Granbury, a Dallas-Fort Worth suburb.

The investment and acquisition deals are expected to close in mid-2026.

Funds managed by Blackstone Tactical Opportunities are contributing to the $1 billion investment. William Nicholson, managing director of Blackstone, called VoltaGrid “a highly differentiated platform addressing one of the most important infrastructure needs of the AI era: reliable, rapidly deployable power. This investment is a strong example of Tac Opps’ focus on providing flexible, scaled capital to exceptional entrepreneurs and businesses operating in Blackstone’s highest-conviction investment themes.”

Nathan Ough, founder and CEO of VoltaGrid, said in a release that the Blackstone investment “is a powerful endorsement of the platform we have built and the role VoltaGrid is playing in delivering the energy infrastructure of the AI era.”

Last October, VoltaGrid and Halliburton said they had forged a partnership to supply power for data centers around the world, with the Middle East picked as the initial target. Two months later, the companies said they had arranged the manufacturing of 400 megawatts of natural gas power systems that’ll be delivered in 2028 to support new data centers in the Eastern Hemisphere.

Jeff Miller, president and CEO of Halliburton, said his company’s investment in VoltaGrid “reflects our shared focus on long-term solutions for the world’s most demanding power environments, and advances VoltaGrid’s ability to deliver reliable, distributed power at scale.”