Revterra was selected from among 10 finalists receiving up to $1 million piloting opportunities. Photo via ADNOC

A Houston sustainability startup has secured a major win on a global scale.

Revterra, which produces novel batteries made from recycled steel, has been awarded a million-dollar piloting opportunity by ADNOC following a global competition.

The ADNOC Decarbonization Technology Challenge, in collaboration with AWS, bp, Hub71, and the Net Zero Technology Centre, sought to find emerging climate tech innovations that are ready for scale.

The contest drew 650 applicants from across 50 countries, and applicants specialized in innovations in oil and gas emissions reduction, nature-based solutions, carbon capture utilization and storage, digital applications, new energies, oil and gas emissions reduction and advanced materials for decarbonization.

At the event in Dubai, Revterra was selected from among 10 finalists receiving up to $1 million piloting opportunities. In addition to the $1 million, they will gain access to facilities and expertise at the ADNOC Research and Innovation Center in Abu Dhabi.

“We are thrilled to win this opportunity,” Patrick Flam, CFO of Revterra, says in a news release. “At Revterra, we have developed an environmentally friendly battery that doesn’t rely on metals like lithium, nickel, or cobalt. Instead, our 2MW batteries are built using recycled steel and rely on rotational energy storage technology to achieve maximum power with a minimal environmental footprint. I am excited to work with our new partners at ADNOC to further develop our solution and deploy it across ADNOC’s operations.”

ADNOC is accelerating the decarbonization of its operations and looks to reduce its carbon intensity by 25 percent by 2030.

“ADNOC is leveraging partnerships and innovative climate technologies to accelerate our decarbonization goals and responsibly enable the energy transition,” Musabbeh Al Kaabi, ADNOC executive director for Low Carbon Solutions and International Growth, adds in the release. “The ADNOC Decarbonization Technology Challenge supports this objective, and we congratulate Revterra for emerging victorious amongst very competitive submissions from around the world.

"We look forward to working with Revterra to unlock cutting-edge solutions that will enhance efficiencies and continue decarbonizing our operations,” he continues.

Carbon Clean develops carbon capture technology for customers such as cement producers, steelmakers, refineries, and waste-to-energy plants.

Clean tech co. with U.S. HQ selected for UAE carbon capture project

big win

Abu Dhabi National Oil Co. (ADNOC), the state-owned oil company of the United Arab Emirates, has chosen technology from United Kingdom-based company Carbon Clean for a carbon capture project in Abu Dhabi. Carbon Clean’s U.S. headquarters is in Houston.

Carbon Clean’s modular CycloneCC technology will be used for a carbon capture project at a Fertiglobe nitrogen fertilizer plant. Fertiglobe is a joint venture between ADNOC and OCI Global, a Netherlands-based chemical company.

“This project is hugely significant given it’s the first industrial deployment of our award-winning CycloneCC technology anywhere in the world,” says Aniruddha Sharma, chairman and CEO of Carbon Clean. “We are moving a step closer to achieving full commercialization of this modular solution, which will play a vital role in decarbonizing heavy industries and achieving net-zero targets.”

Carbon Clean develops carbon capture technology for customers such as cement producers, steelmakers, refineries, and waste-to-energy plants. The company bills its offering as the “world’s smallest industrial carbon capture technology.”

CycloneCC can reduce the cost of carbon capture by as much as 50 percent with a footprint that’s 50 percent smaller than traditional carbon capture units, according to Carbon Clean. The startup’s unit arrives ready to install and can be up and running in eight weeks.

The company established its Houston outpost earlier this year.

In 2022, Houston-based Chevron New Energies led the company’s $150 million series C round. Other contributors to the round were CEMEX Ventures, Marubeni, WAVE Equity Partners, AXA IM Alts, Samsung Ventures, Saudi Aramco Energy Ventures, and TC Energy. To date, Carbon Clean has raised $195 million.

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Houston geothermal company raises $97M Series B

fresh funding

Houston-based geothermal energy startup Sage Geosystems has closed its Series B fundraising round and plans to use the money to launch its first commercial next-generation geothermal power generation facility.

Ormat Technologies and Carbon Direct Capital co-led the $97 million round, according to a press release from Sage. Existing investors Exa, Nabors, alfa8, Arch Meredith, Abilene Partners, Cubit Capital and Ignis H2 Energy also participated, as well as new investors SiteGround Capital and The UC Berkeley Foundation’s Climate Solutions Fund.

The new geothermal power generation facility will be located at one of Ormat Technologies' existing power plants. The Nevada-based company has geothermal power projects in the U.S. and numerous other countries around the world. The facility will use Sage’s proprietary pressure geothermal technology, which extracts geothermal heat energy from hot dry rock, an abundant geothermal resource.

“Pressure geothermal is designed to be commercial, scalable and deployable almost anywhere,” Cindy Taff, CEO of Sage Geosystems, said in the news release. “This Series B allows us to prove that at commercial scale, reflecting strong conviction from partners who understand both the urgency of energy demand and the criticality of firm power.”

Sage reports that partnering with the Ormat facility will allow it to market and scale up its pressure geothermal technology at a faster rate.

“This investment builds on the strong foundation we’ve established through our commercial agreement and reinforces Ormat’s commitment to accelerating geothermal development,” Doron Blachar, CEO of Ormat Technologies, added in the release. “Sage’s technical expertise and innovative approach are well aligned with Ormat’s strategy to move faster from concept to commercialization. We’re pleased to take this natural next step in a partnership we believe strongly in.”

In 2024, Sage agreed to deliver up to 150 megawatts of new geothermal baseload power to Meta, the parent company of Facebook. At the time, the companies reported that the project's first phase would aim to be operating in 2027.

The company also raised a $17 million Series A, led by Chesapeake Energy Corp., in 2024.

Houston expert discusses the clean energy founder's paradox

Guest Column

Everyone tells you to move fast and break things. In clean energy, moving fast without structural integrity means breaking the only planet we’ve got. This is the founder's paradox: you are building a company in an industry where the stakes are existential, the timelines are glacial, and the capital requires patience.

The myth of the lone genius in a garage doesn’t really apply here. Clean energy startups aren’t just fighting competitors. They are fighting physics, policy, and decades of existing infrastructure. This isn’t an app. You’re building something physical that has to work in the real world. It has to be cheaper, more reliable, and clearly better than fossil fuels. Being “green” alone isn’t enough. Scale is what matters.

Your biggest risks aren’t competitors. They’re interconnection delays, permitting timelines, supply chain fragility, and whether your first customer is willing to underwrite something that hasn’t been done before.

That reality creates a brutal filter. Successful founders in this space need deep technical knowledge and the ability to execute. You need to understand engineering, navigate regulation, and think in terms of markets and risk. You’re not just selling a product. You’re selling a future where your solution becomes the obvious choice. That means connecting short-term financial returns with long-term system change.

The capital is there, but it’s smarter and more demanding. Investors today have PhDs in electrochemistry and grid dynamics. They’ve been burned by promises of miracle materials that never left the lab. They don't fund visions; they fund pathways to impact that can scale and make financial sense. Your roadmap must show not just a brilliant invention, but a clear, believable plan to drive costs down over time.

Capital in this sector isn’t impressed by ambition alone. It wants evidence that risk is being retired in the right order — even if that means slower growth early.

Here’s the upside. The difficulty of clean energy is also its strength. If you succeed, your advantage isn’t just in software or branding. It’s in hardware, supply chains, approvals, and years of hard work that others can’t easily copy. Your real competitors aren’t other startups. They’re inertia and the existing system. Winning here isn’t zero-sum. When one solution scales, it helps the entire market grow.

So, to the founder in the lab, or running field tests at a remote site: your pace will feel slow. The validation cycles are long. But you are building in the physical world. When you succeed, you don’t have an exit. You have a foundation. You don't just have customers; you have converts. And the product you ship doesn't just generate revenue; it creates a legacy.

If your timelines feel uncomfortable compared to software, that’s because you’re operating inside a system designed to resist change. And let’s not forget you are building actual physical products that interact with a complex world. Times are tough. Don’t give up. We need you.

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Nada Ahmed is the founding partner at Houston-based Energy Tech Nexus.

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."