Twenty-six Houston-area companies landed on the latest Fortune 500 list. Photo via Getty Images
Houston maintained its No. 3 status this year among U.S. metro areas with the most Fortune 500 headquarters. Fortune magazine tallied 26 Fortune 500 headquarters in the Houston area, behind only the New York City area (62) and the Chicago area (30).
Last year, 23 Houston-area companies landed on the Fortune 500 list. Fortune bases the list on revenue that a public or private company earns during its 2024 budget year.
On the Fortune 500 list for 2025, Spring-based ExxonMobil remained the highest-ranked company based in the Houston area as well as in Texas, sitting at No. 8 nationally. That’s down one spot from its No. 7 perch on the 2024 list. During its 2024 budget year, ExxonMobil reported revenue of $349.6 billion, up from $344.6 billion the previous year.
Here are the rankings and 2024 revenue for the 25 other Houston-area companies that made this year’s Fortune 500:
Nationally, the top five Fortune 500 companies are:
Walmart
Amazon
UnitedHealth Group
Apple
CVS Health
“The Fortune 500 is a literal roadmap to the rise and fall of markets, a reliable playbook of the world's most important regions, services, and products, and an indispensable roster of those companies' dynamic leaders,” Anastasia Nyrkovskaya, CEO of Fortune Media, said in a news release.
Among the states, Texas ranks second for the number of Fortune 500 headquarters (54), preceded by California (58) and followed by New York (53).
Houston-based Envana Software Solutions has received more than $5.2 million in federal and non-federal funding to support the development of technology for the oil and gas sector to monitor and reduce methane emissions.
Thanks to the work backed by the new funding, Envana says its suite of emissions management software will become the industry's first technology to allow an oil and gas company to obtain a full inventory of greenhouse gases.
The funding comes from a more than $4.2 million grant from the U.S. Department of Energy (DOE) and more than $1 million in non-federal funding.
“Methane is many times more potent than carbon dioxide and is responsible for approximately one-third of the warming from greenhouse gases occurring today,” Brad Crabtree, assistant secretary at DOE, said in 2024.
With the funding, Envana will expand artificial intelligence (AI) and physics-based models to help detect and track methane emissions at oil and gas facilities.
“We’re excited to strengthen our position as a leader in emissions and carbon management by integrating critical scientific and operational capabilities. These advancements will empower operators to achieve their methane mitigation targets, fulfill their sustainability objectives, and uphold their ESG commitments with greater efficiency and impact,” says Nagaraj Srinivasan, co-lead director of Envana.
In conjunction with this newly funded project, Envana will team up with universities and industry associations in Texas to:
Advance work on the mitigation of methane emissions
Set up internship programs
Boost workforce development
Promote environmental causes
Envana, a software-as-a-service (SaaS) startup, provides emissions management technology to forecast, track, measure and report industrial data for greenhouse gas emissions.
Founded in 2023, Envana is a joint venture between Houston-based Halliburton, a provider of products and services for the energy industry, and New York City-based Siguler Guff, a private equity firm. Siguler Gulf maintains an office in Houston.
“Envana provides breakthrough SaaS emissions management solutions and is the latest example of how innovation adds to sustainability in the oil and gas industry,” Rami Yassine, a senior vice president at Halliburton, said when the joint venture was announced.
Halliburton Labs has named its latest cohort. Photo courtesy of Halliburton
Halliburton Labs has named five companies to its latest cohort, including one from Texas.
All of the companies are working to help accelerate the future of the energy industry in different ways. The incubator aims to advance the companies’ commercialization with support from Halliburton's network, facilities and financing opportunities.
The five new members include:
360 Energy, an Austin-based in-field computing company with technology that is able to capture flared or stranded gas and monetize it through modular data centers
Cella, a New York-based mineral storage company that provides end-to-end services, from resource assessment to proprietary injection technology, and monitoring techniques to provide geologic carbon storage solutions
Espiku, an engineering services company based in Bend, Oregon, that finds solutions that advance water and minerals recovery from brines and industrial-produced water streams
Mitico, based in Los Angeles, that offers technology services to capture carbon dioxide by using its patent-pending granulated metal carbonate sorption technology (GMC) that captures more than 95% of the CO2 emitted from post-combustion point sources
NuCube, a Pasadena, California-based company with a nuclear fission reactor under development
“We welcome these innovative energy startups,” Dale Winger, managing director of Halliburton Labs, said in a news release. “We are eager to help these participant companies use their time and capital efficiently to progress new solutions that meet industry requirements for cost, reliability, and sustainability.”
Halliburton Labs also announced that it will host the Finalists Pitch Day on March 26, 2025, in Denver for energy and decarbonization industry innovators, startups and investors ahead of the National Renewable Energy Laboratory (NREL) Industry Growth Forum. The pitch event will precede registration and the opening reception of the NREL forum. Find more information here.
Adena Power, an Ohio-based clean energy startup, was the latest to join Halliburton Labs prior to the new cohort. The company used three patented materials to produce a sodium-based battery that delivers clean, safe and long-lasting energy storage.
Adena Power uses three patented materials to produce a sodium-based battery that delivers clean, safe, long-lasting energy storage. Photo via adenapower.com
An Ohio-based clean energy startup has joined Houston-based Halliburton Labs, an incubator for early-stage energy tech companies.
Adena Power uses three patented materials to produce a sodium-based battery that delivers clean, safe, long-lasting energy storage. The startup is trying to capitalize on the 100 terawatt-hour potential for energy storage in the U.S. grid.
“With Halliburton Labs’ support and operational expertise, Adena Power looks to accelerate scaling and take advantage of the high-growth market opportunity,” Nathan Cooley, co-founder and CEO of Adena Power, says in a news release.
Adena, founded in 2022, supplies energy storage batteries for the commercial, industrial, and utility sectors. The startup has collected funding from four investors, according to PitchBook: OhioXcelerate, Third Derivative, BRITE Energy Innovators, and For ClimateTech.
Adena’s addition to Halliburton Labs comes during a momentous year for the company. For example:
Adena won the People’s Choice Award at the National Renewable Energy Labs Industry Growth Forum.
Adena earned the MAKE IT (Manufacture of Advanced Key Energy Infrastructure Technologies) Prize from the U.S. Department of Energy.
“Our team is ready to collaborate with Adena to help them accelerate their growth to meet the demand for behind-the-meter storage solutions,” says Dale Winger, managing director of Halliburton Labs.
Halliburton Labs is a wholly owned subsidiary of Halliburton, a provider of products and services for the energy industry. The incubator will have pitches at the inaugural Houston Energy and Climate Startup Week next month.
According to Halliburton, the pump will offer an “efficient, safe, and agile solution that streamlines geothermal operations and enhances overall performance.” Photo via halliburton.com
Houston-based Halliburton has introduced a new technology that is designed specifically for geothermal energy applications.
The Summit ESP GeoESP is an advanced submersible borehole and surface pump technology GeoESP lifting pumps, which address challenges related to the transport of fluids to the surface through electric submersible pumps (ESP).
According to a news release from Halliburton, the pump will offer an “efficient, safe, and agile solution that streamlines geothermal operations and enhances overall performance.”
The inlet design minimizes power consumption, protects the pump against solids, and tackles scale formation. GeoESP lifting pumps can withstand extreme conditions with the ability to operate at temperatures up to 220°C (428°F) and can resist scale, corrosion, and abrasion.
GeoESP lifting pumps also use standard pump dimensions customized to suit various geothermal well conditions. With that, Halliburton will also offer a digital approach to geothermal well management with the Intelevat data science-driven platform to empower operators with real-time diagnostics and visualizations of “smart” field data. Halliburton states the system will improve well operations, increase production, extend system run life,reduce energy consumption, and minimize shutdowns.
“With increased global focus on low carbon energy sources, we are using our many decades of geothermal production expertise to help our customers maximize safety and improve efficiency,” Vice President of Artificial Lift Greg Schneider says in the release. “GeoESP lifting pumps build upon our current system to minimize power usage and help push the boundaries of what is possible with more complex well designs.”
Recently, more Houston-based companies have invested in geothermal technologies. GA Drilling and ZeroGeo Energy, a Swiss company specializing in renewable energy, announced a 12-megawatt Hot Dry Rock Geothermal Power Plant (Project THERMO), which is the first of several geothermal power and geothermal energy storage projects in Europe.
Additionally, Fervo Energy is exploring the potential for a geothermal energy system at Naval Air Station Fallon in Nevada. Sage Geosystems is working on an exploratory geothermal project for the Army’s Fort Bliss post in Texas. The Bliss project is the third U.S. Department of Defense geothermal initiative in the Lone Star State.
The Department of Energy announced two major initiatives that will reach the Gulf of Texas and Louisiana in U.S. Secretary of Energy Jennifer M. Granholm's address at CERAWeek by S&P Global in March. The Department of Energy’s latest Pathways to Commercial Liftoff report are initiatives established to provide investors with information of how specific energy technologies commercialize and what challenges they each have to overcome as they scale.
"Geothermal has such enormous potential,” she previously said during her address at CERAWEEK. “If we can capture the 'heat beneath our feet,' it can be the clean, reliable, base-load scalable power for everybody from industries to households."
Halliburton and ConocoPhillips were named to the 2023 Dow Jones Sustainability Indices. Photo via halliburton.com
Halliburton and ConocoPhillips were named to the 2023 Dow Jones Sustainability Indices, which assesses the “sustainability performance of companies transparency process” based on an annual S&P Global Corporate Sustainability Assessment.
The CSA evaluates companies’ sustainability practices, and covers over 10,000 companies globally. The CSA has focused on financially material and industry-specific sustainability criteria since 1999.
The methodology of the annual CSA is updated to reflect the objectives to ensure that the CSA captures and delivers high-quality, material sustainability data, and increases efficiency and ease for participating companies. Over 13,000 companies get invited to participate in the CSA, but just 3,500 of the largest companies globally are eligible for inclusion.
In 2023, the DJSI saw a strong response from companies that disclosed their sustainability performance to capital markets through the CSA process.
For Halliburton, 2023 marks the third consecutive year that the company has been named to the prestigious list. Halliburton and ConocoPhillips are the only Houston companies that made the 2023 list.
“At Halliburton, we are constantly developing new and better ways to meet the growing global energy demand while advancing a more sustainable energy future,” Summer Condarco, senior vice president of Service Quality, Continuous Improvement, and Chief HSE Officer, says in a news release. “We are honored to be recognized by the Dow Jones Sustainability Indices for our commitment to sustainability leadership.”
Three Houston companies claimed spots on LexisNexis's 10 Most Innovative Startups in Texas report, with two working in the geothermal energy space.
Sage Geosystems claimed the No. 3 spot on the list, and Fervo Energy followed closely behind at No. 5. Fintech unicorn HighRadius rounded out the list of Houston companies at No. 8.
LexisNexis Intellectual Property Solutions compiled the report. It was based on each company's Patent Asset Index, a proprietary metric from LexisNexis that identifies the strength and value of each company’s patent assets based on factors such as patent quality, geographic scope and size of the portfolio.
Houston tied with Austin, each with three companies represented on the list. Caris Life Sciences, a biotechnology company based in Dallas, claimed the top spot with a Patent Asset Index more than 5 times that of its next competitor, Apptronik, an Austin-based AI-powered humanoid robotics company.
“Texas has always been fertile ground for bold entrepreneurs, and these innovative startups carry that tradition forward with strong businesses based on outstanding patent assets,” Marco Richter, senior director of IP analytics and strategy for LexisNexis Intellectual Property Solutions, said in a release. “These companies have proven their innovation by creating the most valuable patent portfolios in a state that’s known for game-changing inventions and cutting-edge technologies.We are pleased to recognize Texas’ most innovative startups for turning their ideas into patented innovations and look forward to watching them scale, disrupt, and thrive on the foundation they’ve laid today.”
This year's list reflects a range in location and industry. Here's the full list of LexisNexis' 10 Most Innovative Startups in Texas, ranked by patent portfolios.
Fervo Energy fully contracted its flagship 500 MW geothermal development, Cape Station, this spring. Cape Station is currently one of the world’s largest enhanced geothermal systems (EGS) developments, and the station will begin to deliver electricity to the grid in 2026. The company was recently named North American Company of the Year by research and consulting firm Cleantech Group and came in at No. 6 on Time magazine and Statista’s list of America’s Top GreenTech Companies of 2025. It's now considered a unicorn, meaning its valuation as a private company has surpassed $1 billion.
Meanwhile, HighRadius announced earlier this year that it plans to release a fully autonomous finance platform for the "office of the CFO" by 2027. The company reached unicorn status in 2020.
The climate conversation is evolving — fast. It’s no longer just about emissions targets and net-zero commitments. It’s about capital, infrastructure, and execution at industrial scale.
That’s exactly where Yao Huang operates. A seasoned tech entrepreneur turned climate investor, Yao brings sharp clarity to one of the biggest challenges in climate innovation: how do we fund and scale technologies that remove carbon without relying on goodwill or government subsidies?
In this episode of the Energy Tech Startups Podcast, Yao sits down with hosts Jason Ethier and Nada Ahmed for a wide-ranging conversation that redefines how we think about decarbonization. From algae-based photobioreactors that capture CO₂ at the smokestack, to financing models that mirror real estate and infrastructure—not venture capital—Yao lays out a case for why the climate fight will be won or lost on spreadsheets, not slogans.
Her message is as bold as it is practical: this isn’t about saving the planet for the sake of it. It’s about building profitable, resilient systems that scale. And Houston, with its industrial base and project finance expertise, is exactly the place to do it.
The 40-Gigaton Challenge—and a Pandemic Pivot
Yao’s entry into climate wasn’t part of a long-term plan. It was sparked by a quiet moment during the pandemic—and a book.
Reading How to Avoid a Climate Disaster by Bill Gates, she came to two uncomfortable realizations:
The people in power don’t actually have this figured out, and
She would be alive to suffer the consequences.
That insight jolted her out of the traditional tech world and into climate action. She studied at Stanford, surrounded herself with mentors, and began diving into early-stage climate deals. But she quickly realized that most of the solutions she was seeing were still years away from commercialization.
So she narrowed her focus: no R&D moonshots, no science experiments—just deployable solutions that could scale now.
Carbon Optimum: Where Algae Meets Infrastructure
That’s how she found Carbon Optimum, a company using algae photobioreactors to remove CO₂ directly from industrial emissions. Their approach is both elegant and economic:
Install algae reactors next to major emitters like coal and cement plants.
Feed the algae with flue gas, allowing it to absorb CO₂ in a controlled system.
Harvest the algae and convert it into valuable commodities like bio-oils, fertilizer, and food ingredients.
It’s a nature-based solution, enhanced by engineering. One acre of tanks can capture emissions and generate profit—without subsidies.
“This is one of the few solutions I’ve seen that can scale profitably and quickly,” Yao says. “And we’re not inventing anything new—we’re just doing it better.”
The Real Problem? It’s Capital, Not Carbon
As an investor, Yao is blunt: most climate startups are misaligned with the capital markets.
They’re following a tech startup playbook—built for SaaS, not steel. But building climate infrastructure requires a completely different approach: project finance, blended capital, debt structures, carbon credit integration, and regulatory incentives.
“Climate tech is more like real estate or healthcare than software,” Yao explains. “You don’t raise six rounds of venture. You build a stack—grants, equity, debt, tax credits—and you structure your project like infrastructure.”
It’s not just theory. It’s exactly how Carbon Optimum is expanding—through partnerships, offtake agreements, and real-world deployments. And it’s why she believes many climate startups fail: they don’t speak the language of finance.
Houston’s Role in the Climate Capital Stack
For Yao, Houston isn’t just a backdrop—it’s a strategic asset.
The city’s deep bench of project finance professionals, commodity traders, lawyers, and infrastructure veterans makes it uniquely positioned to lead the deployment phase of climate solutions.
“We’ve been calling it the wrong thing,” she says. “This isn’t just about climate—it’s an energy transition. And Houston knows how to build energy infrastructure at scale.”
Still, she notes, the ecosystem needs to evolve. Less education, more execution. Fewer workshops, more closers.
“Houston could be the epicenter of this movement—if we activate the right people and get the right projects over the line.”
From Carbon Capture to Circular Economies
The potential applications of Carbon Optimum’s algae platform go beyond carbon capture. Because the output—algae biomass—can be converted into:
Renewable oil
High-efficiency fertilizers (critical in today’s geopolitically fragile supply chains)
Food ingredients rich in protein and nutrients
Even biochar, a highly stable form of carbon sequestration
It’s scalable, modular, and location-agnostic. In island nations, Yao notes, these systems can offer energy independence by turning waste CO₂ into local energy and fertilizer—without needing to import fuels or food.
“It’s not just emissions reduction. It’s economic sovereignty through circular systems.”
Doing, Not Just Talking
One of Yao’s key takeaways for founders? Don’t waste time. Climate startups don’t have the luxury of trial-and-error cycles stretched over years.
“Founders need to get real about what it takes to scale: talent, capital, storytelling, partnerships. If you’re not ready to do that, maybe you should be a CSO, not a CEO.”
She also points out that founders don’t need to hire everyone—they need to tap the right networks. And in cities like Houston, those networks exist—if you know how to motivate them.
“It takes a different kind of leadership. You’re not just raising money—you’re moving people.”
Why This Episode Matters
This conversation is for anyone who’s serious about scaling real solutions to the climate crisis. Whether you’re a founder navigating capital markets, an investor seeking return and impact, or a policymaker designing the frameworks — Yao Huang offers a grounded, urgent, and actionable perspective.
It’s not about hope. It’s about execution.
Listen to the full episode of the Energy Tech Startups Podcast with Yao Huang:
-- Hosted by Jason Ethier and Nada Ahmed, the Digital Wildcatters’ podcast, Energy Tech Startups, delves into Houston's pivotal role in the energy transition, spotlighting entrepreneurs and industry leaders shaping a low-carbon future.
Rice University chemistry professor László Kürti was named as a recipient of the 2025 Ross M. Brown Investigator Award from the California Institute of Technology’s Brown Institute for Basic Sciences.
Kürti is one of eight mid-career faculty members to receive up to $2 million over five years for their research in the physical sciences.
“I’m greatly honored,” Kürti said in a news release. “We will learn a tremendous amount in the next five years and gain a much clearer understanding of the challenges ahead.”
Kürti was selected for the research he’s been developing for six years on a molecule called tetrahedral N4, which studies show can release large amounts of energy on demand. The molecule can also decompose directly into nitrogen gas without producing carbon dioxide or water vapor. Kürti believes N4 can be used as a "new type of fuel for vehicles."
“Eventually, N4 and other stable, neutral polynitrogen cages could be used to power rockets, helping us reach the moon or Mars faster and with heavier payloads,” he added in this release.
The Brown Investigator Awards were founded by entrepreneur and Caltech alumnus Ross M. Brown and established by the Brown Science Foundation in 2020. The organization has recognized 21 scientists over the last five years.
“Midcareer faculty are at a time in their careers when they are poised and prepared to make profound contributions to their fields,” Brown said in the news release. “My continuing hope is that the resources provided by the Brown Investigator Awards will allow them to pursue riskier innovative ideas that extend beyond their existing research efforts and align with new or developing passions, especially during this time of funding uncertainty.”