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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Engie signs deal to supply wind power for Texas data center

wind deal

Houston-based Engie North America, which specializes in generating low-carbon power, has sealed a preliminary deal to supply wind power to a Cipher Mining data center in Texas.

Under the tentative agreement, Cipher could buy as much as 300 megawatts of clean energy from one of Engie’s wind projects. The financial terms of the deal weren’t disclosed.

Cipher Mining develops and operates large data centers for cryptocurrency mining and high-performance computing.

In November, New York City-based Cipher said it bought a 250-acre site in West Texas for a data center with up to 100 megawatts of capacity. Cipher paid $4.1 million for the property.

“By pairing the data center with renewable energy, this strategic collaboration supports the use of surplus energy during periods of excess generation, while enhancing grid stability and reliability,” Engie said in a news release about the Cipher agreement.

The Engie-Cipher deal comes amid the need for more power in Texas due to several factors. The U.S. Energy Information Administration reported in October that data centers and cryptocurrency mining are driving up demand for power in the Lone Star State. Population growth is also putting pressure on the state’s energy supply.

Last year, Engie added 4.2 gigawatts of renewable energy capacity worldwide, bringing the total capacity to 46 gigawatts as of December 31. Also last year, Engie signed a new contract with Meta (Facebook's owner) and expanded its partnership with Google in the U.S. and Belgium.

Houston researchers make headway on developing low-cost sodium-ion batteries

energy storage

A new study by researchers from Rice University’s Department of Materials Science and NanoEngineering, Baylor University and the Indian Institute of Science Education and Research Thiruvananthapuram has introduced a solution that could help develop more affordable and sustainable sodium-ion batteries.

The findings were recently published in the journal Advanced Functional Materials.

The team worked with tiny cone- and disc-shaped carbon materials from oil and gas industry byproducts with a pure graphitic structure. The forms allow for more efficient energy storage with larger sodium and potassium ions, which is a challenge for anodes in battery research. Sodium and potassium are more widely available and cheaper than lithium.

“For years, we’ve known that sodium and potassium are attractive alternatives to lithium,” Pulickel Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor of Engineering at Rice, said in a news release. “But the challenge has always been finding carbon-based anode materials that can store these larger ions efficiently.”

Lithium-ion batteries traditionally rely on graphite as an anode material. However, traditional graphite structures cannot efficiently store sodium or potassium energy, since the atoms are too big and interactions become too complex to slide in and out of graphite’s layers. The cone and disc structures “offer curvature and spacing that welcome sodium and potassium ions without the need for chemical doping (the process of intentionally adding small amounts of specific atoms or molecules to change its properties) or other artificial modifications,” according to the study.

“This is one of the first clear demonstrations of sodium-ion intercalation in pure graphitic materials with such stability,” Atin Pramanik, first author of the study and a postdoctoral associate in Ajayan’s lab, said in the release. “It challenges the belief that pure graphite can’t work with sodium.”

In lab tests, the carbon cones and discs stored about 230 milliamp-hours of charge per gram (mAh/g) by using sodium ions. They still held 151 mAh/g even after 2,000 fast charging cycles. They also worked with potassium-ion batteries.

“We believe this discovery opens up a new design space for battery anodes,” Ajayan added in the release. “Instead of changing the chemistry, we’re changing the shape, and that’s proving to be just as interesting.”

ExxonMobil lands major partnership for clean hydrogen facility in Baytown

power deal

Exxon Mobil and Japanese import/export company Marubeni Corp. have signed a long-term offtake agreement for 250,000 tonnes of low-carbon ammonia per year from ExxonMobil’s forthcoming facility in Baytown, Texas.

“This is another positive step forward for our landmark project,” Barry Engle, president of ExxonMobil Low Carbon Solutions, said in a news release. “By using American-produced natural gas we can boost global energy supply, support Japan’s decarbonization goals and create jobs at home. Our strong relationship with Marubeni sets the stage for delivering low-carbon ammonia from the U.S. to Japan for years to come."

The companies plan to produce low-carbon hydrogen with approximately 98% of CO2 removed and low-carbon ammonia. Marubeni will supply the ammonia mainly to Kobe Power Plant, a subsidiary of Kobe Steel, and has also agreed to acquire an equity stake in ExxonMobil’s low-carbon hydrogen and ammonia facility, which is expected to be one of the largest of its kind.

The Baytown facility aims to produce up to 1 billion cubic feet daily of “virtually carbon-free” hydrogen. It can also produce more than 1 million tons of low-carbon ammonia per year. A final investment decision is expected in 2025 that will be contingent on government policy and necessary regulatory permits, according to the release.

The Kobe Power Plant aims to co-fire low-carbon ammonia with existing fuel, and reduce CO2 emissions by Japan’s fiscal year of 2030. Marubeni also aims to assist the decarbonization of Japan’s power sector and steel manufacturing industry, chemical industry, transportation industry and various others sectors.

“Marubeni will take this first step together with ExxonMobil in the aim of establishing a global low-carbon ammonia supply chain for Japan through the supply of low-carbon ammonia to the Kobe Power Plant,” Yoshiaki Yokota, senior managing executive officer at Marubeni Corp., added in the news release. “Additionally, we aim to collaborate beyond this supply chain and strive towards the launch of a global market for low-carbon ammonia. We hope to continue to actively cooperate with ExxonMobil, with a view of utilizing this experience and relationship we have built to strategically decarbonize our power projects in Japan and Southeast Asia in the near future.”