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.

Here's what startups took home wins at CERAWeek. Photo by Natalie Harms/InnovationMap

8 energy tech startups recognized at Houston's CERAWeek pitch competition

taking home the W

Over 200 startups participated in CERAWeek this year, and 18 of those companies pitched at a Greater Houston Partnership event.

The Houston Energy Transition Initiative, an initiative to promote Houston's work within the energy transition, hosted its second annual HETI Energy Ventures Competition at CERAWeek Innovation Agora. The competition was divided into four categories. The first batch of startups consisted of five companies from the Texas Entrepreneurship Exchange for Energy, or TEX-E, a collaboration with Greentown Labs, MIT’s Martin Trust Center for Entrepreneurship, and universities across Texas.

The winning startups shared $50,000 of prizes, sponsored by TEX-E. Houston-based Helix Earth Technologies — which has developed high-speed, high-efficiency filter systems derived from technology originating at NASA — won both the first place prize and fan favorite for the category. Helix's co-founders, Rawand Rasheed and Brad Husick from Rice University, walked away with $25,000 in prizes

Founded by Bryon Praslicka, Daniel Zamarron, and Craig Newman from Texas A&M University, Flux Works LLC, and its magnetic gear technology, took second place and $15,000 home. Tierra Climate, a two-sided marketplace for carbon offsets and other sustainability efforts founded by Emma Konet and Jacob Mansfield from Rice University, won third place and $10,000.

Helix Earth Technologies walked away with the top prize of the TEX-E category. Photo via greentownlabs.com

The next sets of startup pitches we broken down by funding stages — pre-seed and seed, series A, and series B and beyond.

Red Shift Energy, uses plasma energy to produce hydrogen from hydrogen sulfide, won fan favorite in the pre-seed and seed category sponsored by HX Venture Fund. A member of Halliburton Labs, the company also was recognized as Chevron favorite.

Per the judging panel, CanaGas won the title of most promising in the pre-seed and seed category sponsored by Alchemy Industrial. The Canadian company liquifies natural gas without costly cryogenics or stripping of the gas.

Houston-based Criterion Energy Partners won both the most-promising series A company category sponsored by SLB, but also the fan favorite series A category sponsored by Guerrella LLC. A geothermal energy tech company, Criterion was also a member of Rice's inaugural Clean Energy Accelerator cohort.

OptiSeis Solutions also won in both categories for the series B track. The company, a geophysical acquisition design and software company, won the title of most promising in the series B category sponsored by Pana LCE Investments and the series B fan favorite category sponsored by Halliburton Labs.

Lastly, the competition named the Most Impactful DEI, a category sponsored by Pana LCE Investments. Austin-based Gazelle Ecosystems, a social innovation startup with eco-solutions for corporations, won that category.

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This article originally ran on InnovationMap.

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Rice University spinouts named among 50 top cleantech companies to watch

green team

Two Rice University spinouts, Coflux Purification and DexMat, appear on a new list of the world’s 50 cleantech companies to watch.

Cleantech Group’s 2026 Cleantech 50 to Watch list recognizes early-stage companies “creating groundbreaking solutions to address some of the world’s most pressing environmental and sustainability challenges.”

Cleantech Group, a market research, consulting, and events company, selects the 50 honorees based on insights from analysts and early-stage innovators, along with public nominations.

Destroying “forever chemicals”

Coflux, founded in 2024, offers an onsite treatment system that captures and destroys manufactured “forever chemicals”—per- and polyfluoroalkyl substances—in water and wastewater. It’s a member of Greentown Houston.

Alec Ajnsztajn, CEO; Jeremy Daum, chief technology officer; and Dana Vazquez, chief commercial officer, co-founded Coflux. Ajnsztajn and Daum earned doctoral degrees from Rice, and Vazquez earned an MBA from the university.

Coflux spun out of Rice labs directed by professors Rafael Verduzco and Pulickel Ajayan.

Last year, Coflux received a $175,000 grant from the U.S. Food and Drug Administration’s National Institute of Food and Agriculture. The startup has also raised more than $500,000 in non-dilutive funding, including $80,000 awarded in 2024 by Rice’s One Small Step Grant program.

Promoting an alternative to copper

DexMat, founded in 2015, produces carbon nanotube products such as fibers, yarns, cables, and fabric. The company’s products address demand for materials that can reduce carbon emissions, according to CB Insights.

Its main product, Galvorn, is a copper alternative made of carbon nanotube fibers. CB Insights says Galvorn is engineered to be lighter and stronger than traditional conductive materials like carbon and steel. It’s used in industries such as energy, aerospace, defense, automotive, consumer electronics, and health care.

DexMat emerged from Matteo Pasquali’s Carbon Lab at Rice. Pasquali, co-founder of DexMat, co-invented the company’s technology with the late Nobel Prize-winning chemist Rick Smalley. Smalley was a professor of chemistry, physics, and astronomy at Rice.

Pasquali is a professor of chemical and biomolecular engineering, chemistry, materials science, and nanoengineering at Rice. He co-founded DexMat with Rice graduate Dmitri Tsentalovich, the company’s director of product innovation.

Earlier this year, DexMat raised $5 million in seed funding from Non Sibi Ventures, Governance Partners, Tailwind Futures, BetterWay, Capital Factory, and other investors. The company also secured $3 million in non-dilutive funding.

In 2023, DexMat raised $3 million in a pre-seed round led by Shell Ventures.

TotalEnergies expands solar joint venture with $1.2B portfolio in Texas, Ohio

solar expansion

TotalEnergies, a French company whose U.S. headquarters is in Houston, announced this month that it is expanding its renewable energy joint venture with New York-based investment firm KKR by adding 700 megawatts of utility-scale solar projects.

The deal will add three utility-scale solar assets in Texas and Ohio, which are expected to reach commercial operation by Q1 2027, according to a news release from the company. The portfolio is valued at $1.2 billion.

The 50/50 joint venture between TotalEnergies and KKR currently holds 1.4 gigawatts of renewable energy and will grow to 2.1 gigawatts.

The new deal is expected to close this year. Once completed, TotalEnergies will operate the assets. The electricity generated from the solar projects will be sold to third parties, the company reports.

The companies originally formed the joint venture about a year ago when TotalEnergies sold KKR a 50 percent stake in a North American solar portfolio valued at $1.25 billion. The deal originally included six utility-scale solar assets, primarily located in the U.S.

“TotalEnergies is a renewable energy industry leader globally, and we are thrilled to establish this joint venture with the TotalEnergies team to support their renewables business," Cecilio Velasco, managing director KKR, said in a release last year. “We have long been investors in renewables through our infrastructure platform, having committed more than $23 billion to date in energy transition investments. TotalEnergies’ North American solar portfolio is a great fit for us, representing high-quality renewable energy assets with long term contracts.”

TotalEnergies reports that by June 2026 it held more than 37 gigawatts of gross renewable power generation capacity. It aims to achieve over 100 terawatt-hours of net electricity production by 2030.

The company signed a major power purchase agreement with Google earlier this year. Through the deal, TotalEnergies will supply the tech giant with 1 gigawatt of solar power for its data centers in Texas over a 15-year span.

However, the company also recently redirected nearly $1 billion in capital away from wind energy projects and "decided to renounce offshore wind development in the United States." Read more here.