Greentown Labs announces newest startups to join Houston climatetech incubator

green team

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.

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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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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.

Houston researchers develop compact carbon capture tech for data centers

AI emissions

Two scientists from the University of Houston have been experimenting with new carbon capture systems that fit inside a standard shipping container, which have the potential to make eliminating carbon output from industrial sites much easier.

The capture of industrial carbon is an important complement to the fight against climate change, as well as winning tax credits for businesses that use carbon capture technology.

The problem is that such systems are often measured in acres, making them expensive to build and extremely power-hungry to actually use. UH Engineering Professor Mim Rahimi and former UH Ph.D. student Ahmad Hassan (now a postdoctoral associate at Harvard) have managed to fit their new system, the Small Modular Electrochemical Container (SMECs), inside a standard 40-foot shipping crate, making them compact and modular enough to be installed almost anywhere for operations of all sizes. Their research was recently published in the journal Environmental Science & Technology.

“With a conventional system, you’re building a 130-foot-tall structure designed for a specific power plant. With our technology, we can adjust the capacity by simply turning containers on or off,” Rahimi said in a news release. “That flexibility is particularly important for data centers, where electricity can come from a combination of natural gas and renewable sources.”

Rahimi and Hassan used simulated gas models to show that under optimal conditions, the SMEC used electrochemically mediated amine regeneration (EMAR) cells developed in Rahimi’s lab to capture 90 percent of carbon under optimal conditions through 300 cycles over 50 hours.

Encouraged, the team then modeled a 360-megawatt natural gas power plant associated with OpenAI’s Stargate AI data center project in Abilene, Texas. In addition to the savings on infrastructure costs, 20 of the researchers’ shipping container systems were able to capture 98 percent of carbon from Stargate’s 875-acre campus based on the model.

The looming energy costs and subsequent carbon emissions from data centers are a real concern. Estimates from the U.S. Department of Energy hypothesize that 12 percent of America’s energy needs could be gobbled up by the centers as soon as 2028. That is a massive new source of carbon. The flexibility of the SMEC means they can be deployed wherever the centers spring up.

“We’re taking a technology that traditionally requires enormous infrastructure and finding a way to fit it inside a shipping container,” Rahimi added in the release. “That opens up entirely new possibilities for how and where carbon capture systems can be used.”

In the future, the researchers say they plan to look at ways to adapt the technology to capture carbon dioxide directly from the atmosphere.

Hertha Metals breaks ground on $100M high-purity iron factory in Conroe

coming soon

Shortly after announcing a $133.65 Series A funding round, Conroe-based Hertha Metals broke ground Oct. 8 on a $100 million factory that will produce steel-grade and magnet-grade high-purity iron.

Hertha’s Chalyx plant, located in Conroe, will manufacture a total of about 10,000 metric tons per year of magnet-grade and steel-grade high-purity iron. The factory will use Hertha’s single-step process to generate high-purity iron for rare-earth-magnet and steel manufacturers in the U.S.

Hertha says Chalyx will be the first U.S. commercial plant for production of magnet-grade high-purity iron.

Chalyx is being built next to Hertha’s headquarters and its Pi100 pilot plant, which will remain in operation. Chalyx and Pi100 will form the first modern-day iron and steel “innovation complex” in the U.S., the company says.

“I founded Hertha Metals because I believed we could significantly improve how the world makes iron and steel from ore, and that an industry so fundamental to our future still had enormous room for invention,” Laureen Meroueh, founder and CEO of Hertha, said in a press release.

The 4-year-old startup says the Chalyx complex will lay the foundation for its first 500,000-ton-per-year steel mill.

Chalyx’s first priority is making high-purity iron for U.S. manufacturers of rare-earth magnets, Hertha says. These magnets are critical components for electric vehicles, data centers, wind turbines and defense systems.

China produces an estimated 94 percent of high-purity iron for rare-earth magnets, according to Hertha.

Aside from iron for rare-earth magnets, Chalyx will make iron and steel for pilot projects in the steel industry.

The plant is expected to come online in late 2027, with production of magnet-grade high-purity iron starting in early 2028.

Today, Hertha employs 32 people, the company says. Once it’s fully operating, the Chalyx plant will employ about 50 people.

Just ahead of the groundbreaking, Hertha announced the $133.65 million Series A round, co-led by Khosla Ventures and Doerr Capital. The round included a $65 million equity investment from the Pentagon.

“Iron and steel have shaped human progress for thousands of years. And I believe there is still an enormous amount left to invent,” Meroueh said at the groundbreaking ceremony.

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