FEATURE
Methane pyrolysis might be the dark horse needed to advance the clean hydrogen economy.
Written by Emily A. Beagle and Michael E. Webber
THE CLEAN HYDROGEN ECONOMY has received a lot of recent attention, including policy goals, trade frameworks, and corporate pledges because the molecule opens pathways toward cleaning up the hardest-to-abate sectors, such as heavy-duty transportation, aviation, and industrial energy. But that discussion occurs mostly through the lens of using renewable electricity for water electrolysis or using steam methane reforming with carbon capture, both of which are expensive and water-intensive ways to make hydrogen.
But there’s another very interesting pathway called methane pyrolysis that combines the relative efficiency of steam methane reformation with the relative cleanliness of electrolysis. Furthermore, it leverages cheap, abundant natural gas rather than relying so extensively on water like electrolysis or steam methane reformation and thus is less likely to run afoul of environmental concerns or other stakeholders in water-scarce regions. Plus, it aligns nicely with the gas industry’s interests and expertise.
Even better, the carbon that is separated from the methane is released as a solid that can be utilized rather than as a gaseous carbon dioxide (CO₂) waste product that wants to float into the atmosphere and thus requires additional handling for capture and long-term disposal. Not only does that solid carbon help methane pyrolysis avoid emissions, but the dark powder is more valuable than the hydrogen because it can be used to make graphite, graphene, carbon nanotubes, soil amendment, battery electrodes, and so forth.
Olive Creek 1, a commercially operational pyrolysis facility in Hallam, Neb., is owned and operated by Nebraska-based Monolith. Its plasma pyrolysis process uses renewable electricity instead of combustion to produce low-emission carbon black and clean hydrogen. Photo: Monolith
Setting the Sustainable Stage
Hydrogen—the first element on the periodic table and the most abundant element in the universe—earned its name because it only generates water (hydro genes in Greek) when burned. That differentiates it from hydrocarbon fuels that generate water vapor alongside pesky CO₂ gases.
This CO₂-free feature makes hydrogen an important tool in the decarbonization toolbox. It has versatility and flexibility as a fuel, feedstock, or energy carrier and has potential applications for reducing emissions across some of the hardest to abate sectors, including steel smelting, cement kilns, glass making, maritime shipping, aviation, and more. For this reason, hydrogen is included as a necessary resource in (almost) all major net-zero energy system studies.
Hydrogen is already an important industrial commodity. Globally, about 100 million metric tons are produced annually for a market size of nearly $200 billion per year. Major end-users include refineries, ammonia manufacturers (for fertilizer), and other industrial facilities that want hydrogen as a process gas or building block for high-value chemicals. Its high energy density per kilogram of mass is especially useful for rocket propulsion.
For all these uses, hydrogen is globally valuable today. It’s just made in a dirty way.
The most common way to produce hydrogen by far is with steam methane reforming or SMR (not to be confused with small modular reactors in the nuclear industry). This series of reactions uses heat, methane (CH₄) and water (H₂O) as inputs and generates gaseous carbon dioxide (CO₂(g)) and hydrogen (H₂) as outputs.
SMR uses these two global reactions, both of which require H₂O.
Methane reforming reaction:
𝐶𝐻₄ + 𝐻₂𝑂 → 𝐶𝑂 + 3𝐻₂
Water-gas shift reaction:
𝐶𝑂 + 𝐻₂𝑂 → 𝐶𝑂₂(𝑔) + 𝐻₂
Overall, SMR is familiar, affordable, and relatively efficient, but dirty and thirsty.
Figure 1. Steam Methane Reforming (SMR) reforms steam and methane into gaseous H₂ and CO₂, the latter of which is usually released into the atmosphere. The heat to drive the reaction also comes from methane.
Hydrogen won’t be useful for cleaning up the economy if it’s made in a dirty way, which is why clean hydrogen production pathways are of interest. For typical energy conversations, the clean hydrogen production pathways that get the most attention are steam methane reforming with carbon capture and storage (SMR+CCS) or renewable electrolysis. The former scrubs the emissions from SMR and the latter makes scrubbing unnecessary.
By adding CCS to an SMR facility, the production emissions can be reduced by 60 to 95 percent (depending on the capture rate and configuration), reaching a life cycle carbon intensity of 0.9–3.6 kilograms of CO₂ emitted per kilogram of H₂ that is produced (for which a shorthand of kgCO₂ /kgH₂ is typically used). These scrubbers make the whole process more water-intensive, too, as carbon capture systems often require water. Even more water might be required depending on the sequestration site. In Iceland, for example, the captured CO₂ is dissolved into water to form a fluid similar to club soda that can be injected into basaltic formations where it will form a solid carbonate that can stay in place for billions of years.
Figure 3. Electrolysis uses electricity to split water into hydrogen and oxygen. Though it is clean at the point of production, the electricity might be generated by dirty power plants.
Figure 2. Steam Methane Reforming with carbon capture and storage (SMR+CCS) reforms steam and methane into gaseous H₂ and CO₂, but capture systems convert 60 to 95 percent of the CO₂ into liquids for long-term sequestration.
While SMR is already popular, CCS for hydrogen applications is much earlier in its technological maturity. Making things pricier, the CO₂ that is captured at SMR+CCS facilities will require pipeline and storage infrastructure, which means additional energy consumption to liquefy, transport, and inject the molecule.
In contrast with SMR, electrolysis uses electrolyzers to split water into hydrogen and oxygen. Notably, there are no CO₂ emissions at the point of production, so if clean power sources such as solar, wind, nuclear, or geothermal are used, then the life cycle carbon intensity will be approximately zero.
The global reaction for electrolysis is:
2H₂O → 2H₂ + O₂
Notably, both of these common production pathways require water as a feedstock for hydrogen.
A Better Pathway
Because water itself is a critical resource, water scarce regions might resist its use for hydrogen production as opposed to other direct human needs such as drinking, cleaning, food preparation, hygiene, and irrigation. Considering the water impacts alongside the life cycle emission impacts of climate technologies will be important for developing effective climate solutions without exacerbating other resource concerns or triggering public resistance because of the potential environmental impacts.
Enter methane pyrolysis: this pathway uses methane as a feedstock, but it is reacted in an oxygen-free environment. Because there is no oxygen in the reactor, the C in the methane (CH₄) forms solid carbon (C(s)) instead of gaseous carbon dioxide (CO₂(g)).
Methane pyrolysis occurs according to the following global reaction:
CH₄ → C(s) + 2H₂
There are many pyrolytic pathways to drive this reaction and separate the hydrogen and carbon: oxypyrolysis, plasma pyrolysis, thermal pyrolysis, catalytic pyrolysis, and so forth. Importantly, the methane pyrolysis reaction does not consume any water as a feedstock—all the produced hydrogen is from the methane fed into the process.
Importantly, the carbon outputs from pyrolysis comprise less total mass and volume. Pyrolysis generates 3 kilograms of solid carbon for every kilogram of H₂, whereas SMR produces 5.5 kilograms of gaseous CO₂ for every molecule of H₂ and the solid C has about one-thousandth the volume of gaseous CO₂.
And because the carbon drops out as a solid, it does not need much supplemental energy—or water-intensive carbon capture systems. It can be easily stored on-site, simplifying its handling. Moreover, that solid carbon product—also called carbon black—is itself valuable for use as a soil amendment, in battery manufacturing, graphite or graphene fabrication, in tires, and so forth.
Figures 4 and 5. Pyrolysis uses heat (usually from methane) and/or electricity to split methane into gaseous hydrogen and solid carbon. It does not require water inputs and skips the requirements for an expensive system to separate gaseous CO₂ from the process stream.
Even better than just avoiding emissions, if renewable natural gas is used as the feedstock and the carbon black is landfilled or embedded in products, methane pyrolysis facilitates a straightforward possibility of producing carbon-negative hydrogen fuels.
One challenge for methane pyrolysis is natural gas consumption. SMR sources its hydrogen from the steam and the methane (the S and the M in SMR). Because all of the hydrogen produced from pyrolysis comes from methane, that pathway requires more natural gas feedstock than steam methane reforming. This could present challenges for the life cycle carbon intensity of methane pyrolysis pathways if the upstream leakage and associated climate impacts of natural gas supply chains are not managed. This also makes pyrolysis not well suited as a feasible hydrogen production pathway in regions that have limited natural gas resources or are concerned about reliance on natural gas for geopolitical or economic reasons.
Compared with the natural gas and electricity input requirements, water consumption and life cycle carbon emissions, pyrolysis needs more gas than SMR but less electricity than electrolysis. Importantly, pyrolysis is carbon clean and water lean.
Figure 6. Hydrogen production needs feedstock (usually water or methane) and energy inputs (usually electricity and/or heat from methane). Methane pyrolysis is useful in regions where water is scarce.
Emily A. Beagle (far left) and Michael E. Webber (second to right) toured Graphitic Energy’s San Antonio pilot plant in June 2025. Photo: Michael E. Webber
ExxonMobil made two announcements in late 2025 as well: it plans to pause its large-scale clean hydrogen facility using reformation and CCS, and also announced that it is launching a partnership with German chemical giant BASF on pyrolysis.
Because of some of the modular elements of methane pyrolysis, as the hydrogen sector gains experience with a greater number of units, progress should follow a technological learning curve of declining costs and increasing productivity.
Pyrolysis was first discussed in the published scientific literature in 1908 (Bone and Coward). Though progress has been slow to date, the flow of money into pyrolysis from government research sponsors, private investors, and large multinational energy companies implies that we are at the cusp of a wave of innovation and subsequent scale-up for pyrolysis. Stable government policy that rewards cleaner energy production and continues to invest in R&D can help accelerate pyrolysis from lab benchtop experiments, pilot plants, and demonstration facilities to large-scale continuous production that cleans up the vital and valuable hydrogen sector.
Taken all together, in areas with abundant and cheap natural gas and electricity but limited water availability, methane pyrolysis for hydrogen production might be a good solution. Such regions include the Permian Basin in West Texas, the Middle East and North Africa, especially the Gulf States, Western Australia, and others.
As the hydrogen economy grows to support decarbonization efforts globally, it will be important to ensure that expanding production does not threaten other critical natural resources, such as water.
Emily A. Beagle is a research associate and lecturer at the Cockrell School of Engineering and LBJ School of Public Affairs at the University of Texas at Austin.
Michael E. Webber is the Cockrell Family Chair #16 in Engineering and Sid Richardson Chair in Public Affairs at the Cockrell School of Engineering and LBJ School of Public Affairs at the University of Texas at Austin.
Depending on the pyrolysis pathway, total resources required for methane pyrolysis can exceed those of SMR+CCS or electrolysis. For example, plasma pyrolysis (which requires the same amount of natural gas feedstock per the fundamental methane pyrolysis reaction) also requires electricity to drive the plasma reaction—about one third to one half of the electricity required for electrolysis. In areas with electricity constraints, thermal pyrolysis, catalytic pyrolysis, or oxypyrolysis might be better suited.
It is for these combinations of reasons that methane pyrolysis companies are attracting attention. Universities and national labs have attracted significant R&D support from agencies like the U.S. government’s ARPA-E (Advanced Research Projects Agency-Energy) and startups have attracted nearly a billion dollars of private venture capital.
Monolith Materials, one of the leading startups, has a facility in Nebraska that has been operational for years. Its plasma pyrolysis process prioritizes the production of carbon black with hydrogen as a byproduct. Graphitic Energy, which spun out of UC Santa Barbara, has a methane oxypyrolysis process that uses a fluidized bed to catalyze its reactions. Its large-scale demonstration facility is at the Southwest Research Institute in San Antonio and the founders claim they can make hydrogen cheaper than traditional methods even without tax credits or subsidies.
Graphitic Energy’s Lighthouse 1 pilot plant began operations in 2024. The facility can produce several hundred kilograms of hydrogen and up to 1,000 kilograms of solid carbon per day during continuous 24/7 operations. Experimental campaigns were planned through the end of 2025. Photo: Graphitic Energy
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