Blue, green, gold — what do all the colors of hydrogen even mean? Photo via Getty Images

Repeated association of specific colors in defined contexts deeply reinforces themes in the human brain. It’s why most students and alumni of Texas A&M University scoff at the sight of burnt orange, and you’d be hard-pressed to find the home of a Longhorn adorned in shades of crimson or maroon.

The color-coding of hydrogen energy production exemplifies one such ambiguous classification methodology, as the seemingly innocuous labeling of hydrogen as green (for hydrogen produced from renewable sources) and black (for hydrogen produced from coal) initially helped to quickly discern which sources of hydrogen are environmentally friendly or not.

But the coding system quickly became more complicated, as the realization that hydrogen extracted from natural gas (aka grey hydrogen) or coal (again, black hydrogen, or sometimes, brown hydrogen, depending on the carbon content and energy density of the source coal) could be extracted in a less harmful way, by introducing methods of carbon capture and storage.

These cleaner methods for hydrogen extraction earned the lofty color coding of blue, just one shade away from green in the rainbow spectrum and a safe distance from the less delightful and inspiring colors grey, brown, and black.

Then along came pyrolysis — a method for producing hydrogen through methane cracking, plainly, the decomposition of methane, CH4, into solid carbon and hydrogen gas, without the introduction of oxygen. This method results in significantly less (if any) creation of carbon dioxide as a by-product. Logic would lead one to categorize this process with a color that lies further away from black than exalted cousin, green hydrogen.

However, the solid carbon that remains after pyrolysis retains over one-third of the original energy available from methane and could tip the GHG scales negatively if not utilized in an environmentally responsible manner, so it’s not a clear-cut winner in the game of lower-carbon energy production. Thus, it is nestled between green and blue and often referred to as “turquoise hydrogen” production.

Other hydrogen production methods — pink, purple, and red — defy rainbow logic as they have all proven to result in higher GHG emissions than the original “clean” queen, green hydrogen, despite following a similar electrolysis process to separate hydrogen and oxygen from one another in its original composition as water. The source of electricity used in the electrolysis process determines the color-code here, as pink hydrogen is generated from nuclear power, red hydrogen is generated from nuclear thermal power, and purple hydrogen is generated from a combination of nuclear power and nuclear thermal power.

Yellow hydrogen seems to not yet have found a clear definition. Some argue it refers to green hydrogen produced exclusively from solar-powered electrolysis, while others claim it to be the child of mixed green/gray hydrogen. Artists should probably keep a far distance from this conversation, unless the energy produced from the steam coming out of their ears could perform electrolysis more cleanly than any of the green hydrogen solutions.

Finally, we have white hydrogen, the naturally occurring, zero-carbon emitting, plentiful element found in the earth’s crust – which is also the least understood of all the hydrogen extraction methodologies.

Remember, hydrogen is the first element in the periodic table, meaning it’s density is very low. Hydrogen knows no bounds, and once it escapes from its natural home, it either floats off into outer space or attaches itself to another element to form a more containable compound, like water.

Many believe white hydrogen to be the unquestionable solution to a lower-carbon energy future but there is still much to be understood. Capturing, storing, and transporting white hydrogen remain mostly theoretical, despite recent progress, which includes one recently announced Houston lab dedicated to hydrogen transport. Another Houston company, Syzygy has raised millions with its light-based catalyst for hydrogen production.

For example, Cemvita, a local Houston chemical manufacturing company, predicts a future powered by gold hydrogen: white hydrogen sourced from depleted oil and gas wells. Many wildcatters believe strongly in a new era of exploration for white hydrogen using techniques refined in oil and gas exploration, including reservoir analysis, drilling, and fracking.

Without a doubt, investigating further the various hydrogen extraction theories is surely a craveable new challenge for the sciences. But perhaps the current color-coding nomenclature for hydrogen needs refinement, as well.

Unless used in the scientific context of wavelength, color-based labels represent an ambiguous classification tool, as the psychology of color depends on modern societal norms. The association of colors with the various hydrogen production methodologies does very little to distinguish the climate impact each method produces. Additionally, the existing categorizations do not consider any further distribution or processing of the produced hydrogen — a simple fact that could easily negate any amount of cleanliness implied by the various production methods — and a topic for a future article.

For now, hydrogen represents one of the front-running sources for a lower-carbon energy future, but it’s up to you if that’s best represented by a blue ribbon, gold medal, white star, or cold-hard greenbacks.

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Lindsey Ferrell is a contributing writer to EnergyCapitalHTX and founder of Guerrella & Co.

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Houston-area company leads Texas businesses on Time's most sustainable list

Spring-based IT company Hewlett Packard Enterprise leads the list of eight Texas businesses that appear in Time magazine’s and data provider Statista’s World’s Most Sustainable Companies list for 2025.

HPE landed at No. 68, earning a score of 74.36 out of 100.

Time and Statista said the ranking highlights corporate responsibility and promotes sustainable practices.

“In an era marked by significant environmental challenges and social inequalities, it is crucial to recognize and reward companies prioritizing sustainability,” according to an article on Time’s website. “By featuring these leading entities, the ranking sets a benchmark for other businesses, fostering transparency and accountability and encouraging the integration of sustainability into core corporate strategies.”

Time and Statista’s ranking process started with a list of more than 5,000 of the world’s largest, most influential companies based on factors such as revenue and public prominence. They identified the top 500 companies based on more than 20 data points.

The process weeded out non-sustainable businesses, such as those involved in producing fossil fuels, and zeroed in on:

  • External sustainability ratings
  • Availability and quality of sustainability reports
  • Performance regarding environmental and social responsibility measures

HPE is targeting net-zero status across its supply chain by 2040. Working toward that goal, the company predicts its carbon emissions will decrease by 33 percent from 2020 to 2028.

“The climate transition demands collective action across our entire value chain, and I am resolute in my commitment to ensure that HPE plays a central role in showcasing the attainability of net-zero emissions through our technologies and actions,” said Antonio Neri, HPE’s president and CEO.

Among the ways HPE is reducing carbon emissions are:

  • Shipping certain products in bigger bundles
  • Incorporating environmentally responsible design
  • Using more renewable energy
  • Improving energy efficiency in buildings
  • Eventually shifting to an all-electric automotive fleet

Here’s a rundown of the eight Texas-based companies that made the sustainability list, including their global rankings and scores.

  • No. 68 Spring-based Hewlett Packard Enterprise. Score: 74.36
  • No. 81 Dallas-based CBRE. Score: 73.49
  • No. 142 Dallas-based AMN Healthcare Services. Score: 69.8
  • No. 165 Austin-based Digital Realty. Score: 68.64
  • No. 257 Round Rock-based Dell Technologies. Score: 64.89
  • No. 295 Frisco-based Keurig Dr Pepper. Score: 63.25
  • No. 335 Dallas-based Jacobs Engineering. Score: 61.98
  • No. 471 Dallas-based AT&T. Score: 57.28

France-based Schneider Electric claimed the top spot on the global list. The company opened a 10,500-square-foot, state-of-the-art Energy Innovation Center in Houston earlier this year.

10+ must-attend Houston energy transition events happening in Q3 2025

Must-Attend Meetings

Editor's note: Q3 is here, and with it, a full slate of must-attend events for Houston energy professionals. On the agenda are casual mixers, exciting showcases, week-long happenings, and more. Mark your calendars for these top Houston energy transition events coming up from July to September 2025, and begin registering today. Please note: this article may be updated to include additional events.

July 17 — TEX-E Energy, Innovation, and Entrepreneurship networking mixer

The Texas Exchange for Energy & Climate Entrepreneurship hosts this casual networking event to connect the Houston energy and climate tech ecosystem.

This event takes place Thursday, July 17 at 5 pm at Second Draught. Click here to register.

July 29 — Center for Houston's Future presents Summer Salon

This year's Summer Salon breakfast program is titled "Digital Technology and AI: Challenges and Opportunities for Driving Energy Innovation." Sponsored by bp, it will feature a timely conversation about the intersection of digital technology (including AI) and energy innovation.

This event takes place Tuesday, July 29 at 7:30 am at Junior League of Houston. Click here to register.

August 21 — Transition on Tap

Greentown Labs’ signature networking event returns in August to foster conversations and connections within Houston's climate and energy transition ecosystem. Entrepreneurs, investors, students, philanthropists, and more are invited to attend, meet colleagues, discuss solutions, and engage with the growing community.

This event takes place Thursday, August 21 at 5:30 pm at Greentown Labs. Click here to register.

August 22 – Determined to Lead Women Lunch: Investing Through Market Cycles with Ellen Wilkirson

EnergyTech Nexus hosts a monthly Determined to Lead Women’s Lunch as part of its ongoing efforts to create safe spaces for women leaders in the energy transition to connect, learn, and lead. The August session features Ellen Wilkirson, principal at Rev Innovations. With deep experience across traditional and transition energy sectors, Wilkirson will share how she’s approached investing through multiple market and commodity cycles and what it means to be a clean energy investor in today’s evolving landscape.

This event takes place Friday, August 22 at 1 pm. Click here to register.

August 27-28 — 6th Texas Energy Forum 2025

The 6th Texas Energy Forum will dive deep into the strategies, policies, and innovative solutions that reinforce energy security for the United States and its allies and fuel economic growth — centered on Texas’ pivotal role in the global energy landscape. Key discussions will address the future of regulatory reform, tariffs, and tax incentives; advancements in oil, gas, and LNG markets; the expansion of power generation; and breakthroughs in EVs and charging infrastructure. This year's topic is "Texas: The Energy Innovation Powerhouse."

This event begins Wednesday, August 27 at the Petroleum Club of Houston. Click here to register.

September 3-4 — 11th Annual Digitalization in Oil & Gas Conference

This conference will delve deep into the intersection of digitalization and decarbonization, highlighting the transformation required for the oil and gas sector to stay relevant, resilient, and achieve business value. This year, the focus is on leveraging AI and generative AI, driving sustainability and workforce development, and achieving operational excellence through digitalization. Key objectives include building future-ready facilities, planning for a lower carbon market, and realizing business value through innovative solutions.

This event begins Wednesday, September 3 at Hilton Americas Houston. Click here to register.

September 8-10 — SPE Energy Transition Symposium

The SPE Energy Transition Symposium brings together professionals from multiple disciplines across the energy sector, offering a comprehensive platform for learning, networking, and collaboration. Its primary objective is to facilitate the exchange and dissemination of knowledge drawn from the insights of industry leaders, technical experts, academics, practitioners, representatives from the financial community, and environmental, social, and governance (ESG) leaders. This year's symposium is titled "Synergizing Innovation and Collaboration: Transforming Energy for a Sustainable Future."

This event begins Monday, September 8 at Houston Marriott Sugar Land. Click here to register.

September 15-19 — Houston Energy & Climate Week

Houston Energy & Climate Week utilizes Houston's potential to propel global climate action. This gathering welcomes an unparalleled selection of global energy leaders and communities, giving participants opportunities to interact and discuss capital, technology, workforce, and policy needs. It is organized by Allies in Energy, a nonprofit dedicated to building energy and climate literacy and a pathway to the workforce of the future.

Following an invite-only dinner on Sunday, September 14, this event begins with Opening Ceremonies on Monday, September 15. Click here for details.

September 15-19 — Houston Energy + Climate Startup Week

Launched in 2024, the official Houston Energy and Climate Startup Week returns for its second year, showcasing how Houston is developing and scaling real solutions for the dual challenge of meeting growing global energy demand while reducing carbon emissions. Join leading energy and climate venture capital investors, industry leaders, and startups from around the world for this showcase of the most innovative companies and technologies that are transforming the energy industry while driving a sustainable, low-carbon energy future.

This event begins Monday, September 15 with a kickoff event at the Ion Plaza. Click here for details.

September 16 — Pilotathon 2025 & Company Showcase

EnergyTech Nexus hosts its annual Pilotathon — a high-impact event designed to fast-track pilot deployments for climate and energy tech startups. Expect a full day of curated startup pitches, a 50-plus company innovation showcase, and direct engagement with corporate partners, investors, and ecosystem leaders. The afternoon will also feature participants from the ETN CoPilot Accelerator. Startup applications and event registration is now open at www.pilotathon.com.

This event takes place Tuesday, September 16 at 8 am at GreenStreet. Click here to register.

September 18 — ACCEL Year 3 Showcase

As part of Houston Energy and Climate Startup Week, Greentown Labs will celebrate ACCEL, an accelerator program for startups led by BIPOC and other underrepresented founders. The third ACCEL cohort will present a showcase featuring their technologies, what they’ve accomplished in the first six months of the program, and where they’re headed next. Attendees will also have the opportunity to network with industry leaders who are passionate about and building an inclusive and sustainable future.

This event takes place Thursday, September 18 at 5 pm at Greentown Labs. Click here to register.

Greentown Labs adds 6 Texas clean energy startups to Houston incubator

green team

Greentown Labs announced the six startups to join its Houston community in Q2 of 2025.

The companies are among a group of 13 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 clean energy applications, from long-duration energy storage systems to 3D solar towers.

The new Houston members include:

  • Encore CO2, a Louisiana-based company that converts CO2 into ethanol, acetate, ethylene and other sustainable chemicals through its innovative electrolysis technology
  • Janta Power, a Dallas-based company with proprietary 3D-solar-tower technology that deploys solar power vertically rather than flatly, increasing power and energy generation
  • Licube, an Austin-based company focused on sustainable lithium recovery from underutilized sources using its proprietary and patented electrodialysis technology
  • Newfound Materials, a Houston-based company that has developed a predictive engine for materials R&D
  • Pix Force, a Houston-based company that develops AI algorithms to inspect substations, transmission lines and photovoltaic plants using drones
  • Wattsto Energy, a Houston-based manufacturer of a long-duration-energy-storage system with a unique hybrid design that provides fast, safe, sustainable and cost-effective energy storage at the microgrid and grid levels

Seven other companies will join Greentown Boston's incubator. See the full list here.

Greentown Houston also added five startups to its local lab in Q1. Read more about the companies here.