seeing green

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

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

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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A View From HETI

Rheom Materials' ShoraiDura was used in an athletic sneaker and a textured skater shoe prototype. Photos courtesy Rheom Materials

A more sustainable shoe can’t be built on a single material swap. From the hard plastics hidden inside a heel to the material covering a sneaker’s upper, footwear is a collection of components—and each presents a different challenge for companies trying to move away from conventional, petroleum-based materials.

Houston-based Rheom Materials wants to change that equation. The biomaterials company has launched a sustainable footwear platform featuring two of its bio-based alternatives: Benree, a biodegradable plastic designed for hard internal components, and ShoraiDura, a durable leather alternative for footwear uppers.

“A shoe is not one material; it is multiple parts working together as a system. Substituting a single material has never moved the needle,” Rheom founder and CEO Zimri Hinshaw said in a news release. “Rheom wants to make it easier for brands to make a positive impact. By providing an assortment of bio-based materials, brands can change the system, not just a swatch of it.”

Benree is Rheom’s alternative to conventional hard plastics used in footwear construction. The company says it is a 100 percent USDA-certified bio-based, biodegradable material with performance comparable to acrylonitrile butadiene styrene (ABS), a widely used engineering plastic.

The material has passed SATRA testing for high-heel applications with Bared Footwear, an Australian footwear brand.

“At Bared, we're constantly on a journey to remove plastic from our shoes. At the same time, our brand won't compromise on quality for the end customer,” Millie Richards, Bared’s head of sustainability, added in the release. “From samples and testing, Rheom has proven to be solving both of those problems for us. We look forward to seeing how they develop as a company and would love to use them in our shoes.”

Rheom says it is also exploring Benree for additional internal components, including toe puffs and heel counters.

Rheom's Benree material was used for a high-heel prototype. Photo courtesy Rheom Materials

The company’s ShoraiDura material addresses another major part of shoe construction: the upper, which must withstand repeated flexing, friction and wear while maintaining its appearance.

Containing about 80 percent bio-based content, ShoraiDura is engineered as a durable leather alternative for footwear. Rheom says the material’s molecular structure is designed to deliver the strength and durability required for demanding applications.

To demonstrate how the material could be used in finished products, Rheom worked with a Los Angeles-based footwear manufacturer to create two prototypes: an athletic sneaker and a textured skater shoe, both featuring ShoraiDura uppers.

The two offerings reflect the company’s broader strategy. Rather than asking brands to evaluate a single material in isolation, Rheom is positioning its platform as a way to explore alternatives across different parts of footwear construction.

The next step is broader industry adoption. Benree’s testing with Bared Footwear and ShoraiDura’s footwear prototypes offer early examples of how the materials could be applied, while commercial use will depend on manufacturers’ evaluations and product-development decisions.

Rheom Materials is a Houston-based biomaterials company developing bio-based alternatives to petrochemical plastics. Its product portfolio includes Shorai, a leather alternative, and Benree, a hard plastic alternative.

The company debuted Shorai at the Houston Livestock Show and Rodeo in 2025 and showed a bio-based "leather" collection in Milan earlier this year. Read more here.

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This article originally appeared on our sister site, InnovationMap.

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