Five companies have joined Greentown Labs Houston, specializing in various "green" applications, from converting plastic waste into sustainable materials to developing energy-storage solutions. Photo courtesy Greentown Labs.

Greentown Labs announced that it added five startups to its Houston community in Q1 of 2025.

The companies are among a group of 19 that joined the climatetech incubator, which is co-located in Houston and Boston, in the same time period. The companies that joined the Houston-based lab specialize in a number of "green" applications, from converting plastic waste into sustainable materials to developing energy-storage solutions.

The new Houston members include:

  • Concept Loop, a project of Pakistan-based Innova8e Inc., aims to repurpose post-industrial and post-consumer plastic waste into sustainable building materials.
  • GeoFuels, a Sugar Land-based company that produces hydrogen by using baseload geothermal power and methane pyrolysis.
  • PLASENE, a Houston-based company with an innovative platform that converts plastic waste into liquid fuel and low-carbon hydrogen through its proprietary catalysts and modular, scalable, pre-engineered units platform. The company was named to Greentown's ACCEL Year 3 cohort earlier this year.
  • RepAir Carbon, an Israeli company with a fully electric, zero-heat carbon-removal technology that consumes minimal energy, operates without liquids or solvents, and produces no hazardous materials or waste.
  • RotorVault from Pasadena, California, is commercializing energy-storage and load-following solutions that are containerized, modular, and field-deployable systems built on flywheel technology.

Fourteen other companies will join Greentown Boston's incubator. See the full list here.

PLASENE and five other new members—Thola, Respire Energy, Andros Innovations, FAST Metals and Tato Labs—join Greentown Labs through its most recent Advancing Climatetech and Clean Energy Leaders Program, or ACCEL, cohort. ACCEL, which works to advance BIPOC-led startups in the climatetech space, announced its third cohort last month.

From potato-starch-based bioplastics startups to companies developing carbon-coated silicon anodes, here's who's joining Greentown Labs and Browning the Green Space's ACCEL program. Photo via browningthegreenspace.org

2 Houston startups join Greentown Labs' BIPOC-led accelerator program

seeing green

Greentown Labs and Browning the Green Space announced the newest cohort for its Advancing Climatetech and Clean Energy Leaders Program, or ACCEL, which works to advance BIPOC-led startups in the climatetech space.

Two Houston companies and one from Austin are among the eight startups to be named to the 2025 group.

“The startups selected for the third ACCEL cohort represent a phenomenal range of energy and climatetech innovations, which underscores our belief that everyone and many solutions must play a role in our community’s collective decarbonization efforts,” Georgina Campbell Flatter, Greentown’s new CEO, said in a release. “We’re proud to welcome these entrepreneurs to our community and eager to see all they’ll achieve throughout the program and beyond!”

Each of the early-stage startups within the cohort will receive $25,000 in non-dilutive grant funding and participate in the year-long program focused on product and technology development, market development, fundraising and management, and team development, according to Greentown. The curriculum is led by VentureWell, a nonprofit with expertise in venture development in climatetech.

The Houston companies include:

  • Carbonext, founded by Olanrewaju Tanimola. The company is leveraging its proprietary, off-the-shelf 3D-graphene technology to develop integrated solutions with carbon-coated silicon anodes to address challenges in the graphite ecosystem, as well as lithium-battery anodes.
  • PLASENE, founded by Sohel Shaikh, Alper Gulludag and Romolo Raciti. The company offers an innovative platform that converts plastic waste into liquid fuel and low-carbon hydrogen through its proprietary catalysts and modular, scalable, pre-engineered units

The remaining six companies are:

  • Inductive Robotics, founded in Austin by Madhav Ayyagari and David Alspaugh. The startup deploys autonomous robots that deliver EV charging directly to parked vehicles in commercial parking facilities, using a subscription-based model.
  • Andros Innovations, founded in Cambridge, Massachusetts by Laron Burrows. The startup has developed a reactor that produces ammonia more cheaply, cleanly and safely than traditional methods do.
  • FAST Metals, founded in Worcester, Massachusetts by Sumedh Gostu and Anthony Staley. It has developed a hydrometallurgical-recovery process capable of extracting iron, aluminum, scandium, titanium, and other rare-earth elements from industrial tailings.
  • Respire Energy, founded in Boston by Dave Hsu, Xiaowei Teng, and Candy Wong. The energy storage startup has developed a safe, low-cost, and long-duration metal-air battery designed for microgrids.
  • Tato Labs, founded in Brooklyn by Mecca McDonald and Mia Dunn. It is developing scalable, innovative, bioplastic products and packaging solutions that leverage potato starch, protect and preserve the natural ecosystem, and minimize plastic waste.
  • Thola, founded in Portland, Maine, by Nneile Nkholise and Lerato Takana. The company provides an on-demand marketplace for commercial-building sustainability and safety management, with a mission to decarbonize old buildings.

ACCEL is supported by the Massachusetts Clean Energy Center (MassCEC), Shell, Equinor, the Growth Capital Division of MassDevelopment, Microsoft and the Barr Foundation.

The accelerator has supported 13 early-stage startups since it was founded in 2023, resulting in $325,000 in grant funding. Houston companies have been represented in each cohort. Click here to see the 2024 cohort and here to see the inaugural 2023 cohort.

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Gold H2 harvests clean hydrogen from depleted California reservoirs in first field trial

breakthrough trial

Houston climatech company Gold H2 completed its first field trial that demonstrates subsurface bio-stimulated hydrogen production, which leverages microbiology and existing infrastructure to produce clean hydrogen.

Gold H2 is a spinoff of another Houston biotech company, Cemvita.

“When we compare our tech to the rest of the stack, I think we blow the competition out of the water," Prabhdeep Singh Sekhon, CEO of Gold H2 Sekhon previously told Energy Capital.

The project represented the first-of-its-kind application of Gold H2’s proprietary biotechnology, which generates hydrogen from depleted oil reservoirs, eliminating the need for new drilling, electrolysis or energy-intensive surface facilities. The Woodlands-based ChampionX LLC served as the oilfield services provider, and the trial was conducted in an oilfield in California’s San Joaquin Basin.

According to the company, Gold H2’s technology could yield up to 250 billion kilograms of low-carbon hydrogen, which is estimated to provide enough clean power to Los Angeles for over 50 years and avoid roughly 1 billion metric tons of CO2 equivalent.

“This field trial is tangible proof. We’ve taken a climate liability and turned it into a scalable, low-cost hydrogen solution,” Sekhon said in a news release. “It’s a new blueprint for decarbonization, built for speed, affordability, and global impact.”

Highlights of the trial include:

  • First-ever demonstration of biologically stimulated hydrogen generation at commercial field scale with unprecedented results of 40 percent H2 in the gas stream.
  • Demonstrated how end-of-life oilfield liabilities can be repurposed into hydrogen-producing assets.
  • The trial achieved 400,000 ppm of hydrogen in produced gases, which, according to the company,y is an “unprecedented concentration for a huff-and-puff style operation and a strong indicator of just how robust the process can perform under real-world conditions.”
  • The field trial marked readiness for commercial deployment with targeted hydrogen production costs below $0.50/kg.

“This breakthrough isn’t just a step forward, it’s a leap toward climate impact at scale,” Jillian Evanko, CEO and president at Chart Industries Inc., Gold H2 investor and advisor, added in the release. “By turning depleted oil fields into clean hydrogen generators, Gold H2 has provided a roadmap to produce low-cost, low-carbon energy using the very infrastructure that powered the last century. This changes the game for how the world can decarbonize heavy industry, power grids, and economies, faster and more affordably than we ever thought possible.”

Rice University spinout lands $500K NSF grant to boost chip sustainability

cooler computing

HEXAspec, a spinout from Rice University's Liu Idea Lab for Innovation and Entrepreneurship, was recently awarded a $500,000 National Science Foundation Partnership for Innovation grant.

The team says it will use the funding to continue enhancing semiconductor chips’ thermal conductivity to boost computing power. According to a release from Rice, HEXAspec has developed breakthrough inorganic fillers that allow graphic processing units (GPUs) to use less water and electricity and generate less heat.

The technology has major implications for the future of computing with AI sustainably.

“With the huge scale of investment in new computing infrastructure, the problem of managing the heat produced by these GPUs and semiconductors has grown exponentially. We’re excited to use this award to further our material to meet the needs of existing and emerging industry partners and unlock a new era of computing,” HEXAspec co-founder Tianshu Zhai said in the release.

HEXAspec was founded by Zhai and Chen-Yang Lin, who both participated in the Rice Innovation Fellows program. A third co-founder, Jing Zhang, also worked as a postdoctoral researcher and a research scientist at Rice, according to HEXAspec's website.

The HEXASpec team won the Liu Idea Lab for Innovation and Entrepreneurship's H. Albert Napier Rice Launch Challenge in 2024. More recently, it also won this year's Energy Venture Day and Pitch Competition during CERAWeek in the TEX-E student track, taking home $25,000.

"The grant from the NSF is a game-changer, accelerating the path to market for this transformative technology," Kyle Judah, executive director of Lilie, added in the release.

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This article originally ran on InnovationMap.