Twelve local startups have joined Greentown Houston, along with others from around the world. Photo courtesy Greentown Labs.

More than 40 climatetech startups joined the Greentown Labs Houston community in the second half of 2025. Twelve hail from the Bayou City.

The companies are among a group of nearly 70 that joined the climatetech incubator, which is co-located in Houston and Boston, in Q3 and Q4.

The new companies that have joined the Houston incubator specialize in a variety of clean energy applications, from green hydrogen-producing water-splitting cycles to drones that service wind turbines.

The local startups that joined Greentown Houston include:

  • Houston-based Wise Energie, which delivers turnkey microgrids that blend vertical-axis wind, solar PV, and battery storage into a single, silent system.
  • The Woodlands-based Resollant, which is developing compact, zero-emissions hydrogen and carbon reactors to provide low-cost, scalable clean hydrogen and high-purity carbon for the energy and manufacturing sectors.
  • Houston-based ClarityCastle, which designs and manufactures modular, soundproof work pods that replace traditional drywall construction with reusable, low-waste alternatives made from recycled materials.
  • Houston-based WattSto Energy, which manufactures vanadium redox flow batteries to deliver long-duration storage for both grid-scale projects and off-grid microgrids.
  • Houston-based AMPeers, which delivers advanced, high-temperature superconductors in the U.S. at a fraction of traditional costs.
  • Houston-based Biosimo, which is developing bio-based platform chemicals, pioneering sustainable chemistry for a healthier planet and economy.
  • Houston-based Ententia, which offers purpose-built, generative AI for industry.
  • Houston-based GeoKiln Energy Innovation, which is developing a new way to produce clean hydrogen by accelerating natural geologic reactions in iron-rich rock formations using precision electrical heating.
  • Houston-based Timbergrove, which builds AI and IoT solutions that connect and optimize assets—boosting visibility, safety, and efficiency.
  • Houston-based dataVediK, which combines energy-domain expertise with advanced machine learning and intelligent automation to empower organizations to achieve operational excellence and accelerate their sustainability goals.
  • Houston-based Resonant Thermal Systems, which uses a resonant energy-transfer (RET) system to extract critical minerals from industrial and natural brines without using membranes or grid electricity.
  • Houston-based Torres Orbital Mining (TOM),which develops autonomous excavation systems for extreme environments on Earth and the moon, enabling safe, data-driven resource recovery and laying the groundwork for sustainable off-world industry.

Other startups from around the world joined the Houston incubator in the same time period, including:

More than 100 startups joined Greentown this year, according to an end-of-year reflection shared by Greentown CEO Georgina Campbell Flatter.

Flatter joined Greentown in the top leadership role in February 2025. She succeeded former CEO and president Kevin Knobloch, who stepped down in July 2024.

"I moved back to the United States in March 2025 after six years overseas—2,000 miles, three children, and one very patient husband later. Over these months, I’ve had the chance to hear from the entrepreneurs, industry leaders, investors, and partners who make this community thrive. What I’ve experienced has left me brimming with urgent optimism for the future we’re building together," she said in the release.

According to Flatter, Greentown alumni raised more than $2 billion this year and created more than 3,000 jobs.

"Greentown startups and ecosystem leaders—from Boston, Houston, and beyond—are showing that we can move further and faster together. That we don’t have to choose between more energy or lower emissions, or between increasing sustainability and boosting profit. I call this the power of 'and,'" Flatter added. "We’re working for energy and climate, innovation and scale, legacy industry and startups, prosperity for people and planet. The 'and' is where possibility expands."

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Fervo promotes strategy leader to COO as flagship geothermal project nears launch

new leader

Houston geothermal unicorn Fervo Energy has named Sarah Jewett as its new COO.

Jewett steps into the role as the company prepares for its flagship Cape Station geothermal project to deliver its first power later this year.

Jewett joined Fervo in 2020 as director of strategy and most recently served as the company's senior vice president of strategy. She spoke with HETI on the potential of geothermal energy in 2024.

Before Fervo, Jewett served as senior director of corporate development for Houston-based Select Energy Services. She ran hydraulic fracturing crews for Schlumberger in the Permian Basin and Alaska's North Slope early in her career.

In the COO role, Jewett is tasked with creating "the centralized infrastructure required to execute on what the company believes is the most significant commercial opportunity for clean, firm power in history," according to a company release.

“What Sarah has built over the last six years has been foundational to the company’s success. From the time she joined, she has brought an unwavering people-first mindset and outstanding dedication to building things that last,” Tim Latimer, CEO and co-founder of Fervo, added in the release. “As we move into the next phase of our growth, there is no better person to lead the operating core of this company.”

Jewett holds an MBA from Harvard Business School and a bachelor's degree in mechanical engineering from Dartmouth College.

Fervo announced the addition of four heavyweights to its board of directors this spring, including Meg Whitman, former CEO of eBay, Hewlett-Packard, and Spring-based HPE. Shortly after, the company filed for its highly anticipated $1 billion-plus IPO. Read more here.

UH study finds Gulf Coast best positioned for emerging carbon removal technology

coastal impact

The Gulf Coast is an ideal spot for deploying a new ocean-based carbon removal technology that uses seawater to capture and store carbon dioxide, according to a new study from the University of Houston.

The study was led by UH Cullen College of Engineering Professor Mim Rahimi and published in Nature’s Communications Sustainability journal. Abdelrahman Refaie, a PhD student at UH, authored the paper. It aimed to develop a plan for implementing an electrochemical marine carbon dioxide removal (e-mCDR) technology that treats seawater to increase the ocean’s ability to absorb and store carbon dioxide from the air.

Currently, oceans absorb about 30 percent of human-produced carbon dioxide emissions each year, according to UH, making it a great natural resource for carbon removal.

The team at UH scouted and analyzed 38 coastal facilities across the U.S.—including power plants, desalination plants, and liquefied natural gas (LNG) terminals—before determining the Gulf Coast as an attractive option. The South Hub, or the Gulf Coast along Texas and Louisiana, ranked the top-performing area for the technology due to the industrial infrastructure, affordable electricity, hydrogen transportation and storage networks.

Other regions like California and the Northeast also scored well due to their clean energy mix and carbon removal potential, according to UH.

“The South hub has one of the highest diversity factors between power plants, desalination and LNG,” Refaie said in a news release. “That means if, logistically, down the road LNG is not open for this implementation, then we have another option in the area. It reduces the risk factor.”

UH says the findings show how companies could commercialize the technology, which could boost coastal economies.

“The question we had wasn’t technical, rather, it was logistical in regard to implementation down the road,” Rahimi said. “This would be a roadmap if a company or the government wants to utilize this technology.”

Rahimi aims to increase awareness about e-mCDR technology and its potential impact. He recently discussed the ocean-centric carbon removal work with members of Congress in March at the Carbon to Sea’s 2026 Hill Day.

“I think faculty at the University of Houston can do more of this kind of work,” Rahimi said in a separate release. “Meeting with Members of Congress gives us a chance to help policymakers better understand the science and engineering happening at our university. That kind of engagement is an important part of moving new technologies forward. It also shows how the work we do on campus can have a real impact on communities beyond the university.”