Rice Alliance Energy Tech Venture Forum names most-promising startups

big winners

Ten climatetech startups were named most-promising at this annual Rice Alliance Energy Tech Venture Forum. Photo courtesy Rice Alliance.

Investors at the Rice Alliance Energy Tech Venture Forum have named the 10 most-promising startups among the group of 100 clean tech companies participating in the event.

The 22nd annual event was held yesterday, Sept. 18, at Rice University’s Jones Graduate School of Business and was part of the second Houston Energy and Climate Startup Week.

The most-promising startups will receive $7,000 in in-kind legal services from Baker Botts.

The 10 most-promising companies included:

Houston-based Xplorobot, which has developed laser gas imaging technology for the first handheld methane detection device approved by the EPA as an alternative test method
Seattle-based Badwater Alchemy, a desalination company that uses nano materials to purify saline water at a fraction of the cost of traditional methods
San Francisco-based Ammobia, which is developing a clean ammonia production process
Illinois-based Celadyne Technologies, which is building hydrogen for industrial decarbonization with durable and efficient fuel cells and electrolyzers
Massachusetts-based MacroCycle Technologies, which converts plastic waste in the form of bottles, food trays and polyester textiles into virgin-grade mPET resin
Massachusetts-based AtoMe, which uses nano-ceramics to develop ultra-durable metals for 3D printing
Colorado-based Advanced Thermovoltaic Systems (ATS) Energy, a renewable energy semiconductor manufacturing company
North Carolina-based Lukera Energy, which is converting waste methane into high-value fuel
Midland, Texas-based AI Driller, a company that uses AI and machine learning to enable remote operations and provide historical drilling data for survey management, anti-collision monitoring and iob reporting
New York-based Fast Metals Inc., which has developed a chemical process to extract valuable metals from complex toxic mine tailings that is capable of producing iron, aluminum, scandium, titanium and other rare earth elements using industrial waste and waste CO2 as inputs

Arculus Solutions won the People's Choice Award. The New Jersey-based company retrofits natural gas pipelines for safe hydrogen transportation. It also won Track A: Hydrogen, Fuel Cells, Buildings, Water, & Other Energy Solutions at the Energy Venture Day and Pitch Competition during CERAWeek earlier this year.

The 100 energy technology ventures selected to participate in the forum were named earlier this year. See the full list here.

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Houston Energy and Climate Startup Week returns Sept. 15-19. Photo via rice.edu

8+ can't-miss events at Houston Energy and Climate Startup Week 2025

where to be

Editor's note: This article may be updated to include additional events.

The second annual Houston Energy and Climate Startup Week is less than a month away—and the calendar of events is taking shape.

The series of panels, happy hours and pitch days will take place Sept. 15-19. The Ion District will host many of the week's events.

Here are the details on some of the can't-miss events of the week:

Houston Energy & Climate Startup Week Kickoff Panel and Block Party

Join fellow innovators, founders, investors and energy leaders at this kick-off event hosted by The Ion and HETI, which will feature brief welcome remarks, a panel discussion and networking, followed by a block party on the Ion Plaza.

This event is Monday, Sept. 15, at 4 p.m. at The Ion. Register here.

Energytech Nexus Pilotathon

Grab breakfast and take in keynotes and panels by leaders from New Climate Ventures, V1 Climate, Halliburton, Energy Tech Nexus and many others. Then hear pitches during the Pilotathon, which targets startups ready to implement pilot projects within six to 12 months.

This event is Tuesday, Sept. 16, from 8 a.m.-5 p.m. at GreenStreet. Get tickets here.

Meet the Activate Houston Cohort 2025 Fellows

Meet Activate's latest cohort, which was named this summer, and also learn more about its 2024 group.

This event is Tuesday, Sept. 16, at 5 p.m. at the Ion. Register here.

New Climate Ventures Afterparty

Enjoy music, networking and carbon-negative spirits at Axelrad. Houston startups Quaise Energy, Solidec, Dimensional Energy, Rheom Materials, and Active Surfaces will also be on-site.

This event is Tuesday, Sept. 16, from 6:30-9:30 p.m. at Axelrad. Register here.

Green ICU Conference: Sustainability in Health Care for a Healthier Future

Houston Methodist will host its inaugural Green ICU Conference during Houston Energy & Climate Week. The conference is designed to bring together healthcare professionals, industry leaders, policymakers and innovators to explore solutions for building a more sustainable healthcare system.

This event is Wednesday, Sept. 17. from 8 a.m.-3 p.m. at TMC Helix Park. Register here.

Rice Alliance Energy Tech Venture Forum

Hear from clean energy startups from nine countries and 19 states at the 22nd annual Energy Tech Venture Forum. The 12 companies that were named to Class 5 of the Rice Alliance Clean Energy Accelerator will present during Demo Day to wrap up their 10-week program. Apart from pitches, this event will also host keynotes from Arjun Murti, partner of energy macro and policy at Veriten, and Susan Schofer, partner at HAX and chief science officer at SOSV. Panels will focus on corporate innovation and institutional venture capital.

This event is Thursday, Sept. 18, from 7:30 a.m.-5 p.m. at Rice University’s Jones Graduate School of Business. Register here.

Shell STCH Open House

Get a behind-the-scenes look at how Shell is leveraging open innovation to scale climate tech. The open house will spotlight two Houston-based startups—Mars Materials, which converts captured CO2 into acrylonitrile, and DexMat, which transforms methane into high-performance carbon nanotube fibers.

This event is Thursday, Sept. 18, from 8:30 a.m.-12:15 p.m. at Shell Technology Center. Register here.

ACCEL Year 3 Showcase

Celebrate Advancing Climatetech and Clean Energy Leaders Program, or ACCEL, an accelerator program for startups led by BIPOC and other underrepresented founders from Greentown Labs and Browning the Green Space. Two Houston companies and one from Austin are among the eight startups to be named to the 2025 group. Hear startup pitches from the cohort, and from Greentown's Head of Houston, Lawson Gow, CEO Georgina Campbell Flatter and others.

This event is Thursday, Sept. 18, from 5-8 p.m. at Greentown Labs. Get tickets here.

Halliburton Labs Finalists Pitch Day

Hear from Halliburton Labs' latest cohort of entrepreneurs. The incubator aims to advance the companies’ commercialization with support from Halliburton's network, facilities and financing opportunities. Its latest cohort includes one company from Texas.

This event is Friday, Sept. 19, from 8 a.m.-noon at The Ion. Register here.

Chevron Energy Innovation Finals

The University of Houston will present the 4th Annual Chevron Innovation Commercialization Competition.

The event is Friday, Sept. 19, from 10 a.m.-1:30 p.m. at the University of Houston. Register here.

Houston Energy and Climate Startup Week was founded in 2024 by Rice Alliance for Technology and Entrepreneurship, Halliburton Labs, Greentown Labs, Houston Energy Transition Initiative (HETI), Digital Wildcatters and Activate.

Last year, Houston Energy and Climate Startup Week welcomed more than 2,000 attendees, investors and industry leaders to more than 30 events. It featured more than 100 speakers and showcased more than 125 startups.

Houston Energy and Climate Startup Week is coming back for a second year. Photo via GHP

Houston Energy and Climate Startup Week announces 2025 dates, key events

comeback tour

Six local organizations focused on the energy transition have teamed up to bring back Houston Energy and Climate Startup Week.

The second annual event will take place Sept. 15-19, according to an announcement. The Ion District will host many of the week's events.

“Houston Energy and Climate Startup Week was created to answer a fundamental question: Can we achieve more by working together than we can alone?” Jane Stricker, senior vice president at the Greater Houston Partnership and executive director of HETI, said in the release.

So far, events for the 2025 Houston Energy and Climate Startup Week include an introduction to climatetech accelerator Activate's latest cohort, the Rice Alliance Energy Tech Venture Forum, a showcase from Greentown Labs' ACCEL cohort, and Halliburton Labs Pitch Day.

Houston organizations New Climate Ventures and Digital Wildcatters, along with Global Corporate Venturing, are slated to offer programming again in 2025. And new partners, Avatar Innovations and Decarbonization Partners, are slated to introduce events. Find a full schedule here.

Other organizations can begin entering calendar submissions starting in May, according to the release.

"In 2024, we set out to build something with lasting impact—rooted in the ingenuity of Houston’s technologists and founders. Thanks to a collaborative effort across industry, academia, and startups, we’ve only just begun to showcase Houston’s strengths and invite others to be part of this movement," Stricker added in the release. "We can’t wait to see the city rise to the occasion again in 2025.”

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Houston maritime startup raises $43M to electrify cargo vessels

A Houston-based maritime technology company that is working to reduce emissions in the cargo and shipping industry has raised VC funding and opened a new Houston headquarters.

Fleetzero announced that it closed a $43 million Series A financing round this month led by Obvious Ventures with participation from Maersk Growth, Breakthrough Energy Ventures, 8090 Industries, Y Combinator, Shorewind, Benson Capital and others. The funding will go toward expanding manufacturing of its Leviathan hybrid and electric marine propulsion system, according to a news release.

The technology is optimized for high-energy and zero-emission operation of large vessels. It uses EV technology but is built for maritime environments and can be used on new or existing ships with hybrid or all-electric functions, according to Fleetzero's website. The propulsion system was retrofitted and tested on Fleetzero’s test ship, the Pacific Joule, and has been deployed globally on commercial vessels.

Fleetzero is also developing unmanned cargo vessel technology.

"Fleetzero is making robotic ships a reality today. The team is moving us from dirty, dangerous, and expensive to clean, safe, and cost-effective. It's like watching the future today," Andrew Beebe, managing director at Obvious Ventures, said in the news release. "We backed the team because they are mariners and engineers, know the industry deeply, and are scaling with real ships and customers, not just renderings."

Fleetzero also announced that it has opened a new manufacturing and research and development facility, which will serve as the company's new headquarters. The facility features a marine robotics and autonomy lab, a marine propulsion R&D center and a production line with a capacity of 300 megawatt-hours per year. The company reports that it plans to increase production to three gigawatt-hours per year over the next five years.

"Houston has the people who know how to build and operate big hardware–ships, rigs, refineries and power systems," Mike Carter, co-founder and COO of Fleetzero, added in the release. "We're pairing that industrial DNA with modern batteries, autonomy, and software to bring back shipbuilding to the U.S."

Shell partners with UK-based co. for hydrogen electrolyzer pilot

ultra-efficient electrolyzer

Shell Global Solutions International, a subsidiary of Shell, which maintains its U.S. headquarters in Houston, has signed a collaboration agreement with London-based Supercritical Solutions to advance Supercritical’s ultra-efficient hydrogen electrolyzer technology toward a field pilot demonstration.

In the deal, the companies will collaborate on a paid technology feasibility study that will support the evaluation and planning of the pilot demonstration, according to a news release. Supercritical Solutions’ technology aims to deliver high-efficiency renewable hydrogen at a lower cost for the industrial hydrogen market.

"Signing this collaboration agreement with Shell is a major milestone for Supercritical Solutions and an important step on our commercialisation journey,” Luke Tan, co-founder of Supercritical, said in the news release. “We are directly addressing the cost and complexity barriers facing the renewable hydrogen market. We are excited to move forward with a company like Shell, whose global leadership has been proven to accelerate innovative technologies to market.”

Supercritical’s hydrogen electrolyser technology can operate at high temperatures and pressures of up to 220 bar without the need for an external hydrogen compressor, rare-earth materials or easily degradable membranes. The technology removes the typical compression step in the process while delivering hydrogen at industry standards. It requires significantly less energy than many traditional electrolyzers and is more cost-efficient.

This recent investment builds on an ongoing relationship between Shell and Supercritical. Supercritical was founded in 2020 and was runner-up in Shell’s New Energy Challenge, which helps startups and scaleups develop sustainable technologies, in 2021. Shell Ventures then invested in Supercritical’s Series A funding round in 2024 with Toyota Ventures.

3 Houston-area companies named to Global Cleantech 100

Energized

Three Houston-area companies—Amperon, Hertha Metals and Vaulted Deep—appear on this year’s Global Cleantech 100 list.

The unranked list, generated by market intelligence and advisory firm Cleantech Group, identifies the 100 privately held companies around the world that are most likely to make a significant impact in the cleantech market over the next five to 10 years.

For the 2026 list, Cleantech Group received more than 24,000 Global Cleantech 100 nominations from nearly 60 countries. Cleantech Group scored those companies and narrowed the contenders to 264. An expert panel reviewed those nominees, and the list was whittled down to the 100 winners.

Here’s a rundown of the three Houston-area honorees:

Amperon

Founded in 2018 by Sean Kelly and Abe Stanway, Houston-based Amperon offers an AI-enabled energy forecasting and analytics platform designed to help stabilize electric grids. Amperon received undisclosed amounts of venture capital from National Grid Partners and Tokyo Gas Co. Ltd. last year and announced a recent investment from Samsung Ventures earlier this month.

Hertha Metals

Founded in 2022 by Laureen Meroueh, Conroe-based Hertha Metals provides a single-step process for producing sustainable steel. Last year, the company emerged from stealth mode and raised more than $17 million in venture capital.

Vaulted Deep

Vaulted Deep’s technology injects excess organic waste underground to remove carbon dioxide from the atmosphere. Julia Reichelstein and Omar Abou-Sayed founded the Houston-based company in 2023. Last year, the startup raised $32.3 million in venture capital. Also in 2025, Vaulted Deep signed a 12-year deal with software giant Microsoft to remove up to 4.9 million metric tons of carbon dioxide from the environment.

Vaulted Deep also made the list last year, along with Houston-based Syzygy Plasmonics and Fervo Energy. Fervo was also named the 2025 North American Company of the Year by Cleantech Group.

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