Circularity Fuels Completes World-First End-to-End Conversion of Raw Dairy Biogas into Sustainable Aviation Fuel
Circularity Fuels has announced a major milestone in the development of sustainable aviation fuel (SAF), revealing the successful completion of the world’s first end-to-end conversion of raw agricultural biogas into drop-in jet fuel. The achievement was demonstrated through a six-month pilot program in California, where biogas sourced directly from a dairy farm manure digester was converted into ASTM-compliant SAF suitable for commercial aviation use.
The pilot produced jet fuel meeting ASTM D7566 Annex A1 specifications (Fischer-Tropsch Synthetic Paraffinic Kerosene, or FT-SPK), marking a significant validation of the company’s modular conversion technology. According to Circularity Fuels, the breakthrough demonstrates that SAF production from waste biogas can be achieved at a projected installed capital cost of less than $100,000 per barrel-per-day of capacity at commercial scale—roughly one-fifth the cost of many SAF facilities currently under development in Europe. The company says this cost structure could enable SAF derived from agricultural biogas to compete directly with fossil jet fuel on price.
Addressing Aviation’s Fuel Challenge
The aviation sector continues to face mounting pressure over fuel security, price volatility, and decarbonization. Jet fuel markets have been affected by geopolitical instability and fluctuating crude oil supply chains, leading to persistent cost uncertainty for airlines and passengers alike.
Sustainable aviation fuel has emerged as a key pathway to reducing emissions in aviation, but global production remains extremely limited. SAF currently accounts for less than 1% of total jet fuel consumption worldwide, leaving the sector heavily dependent on conventional fossil-based fuels.
Today’s SAF market is largely dominated by feedstocks such as used cooking oil and waste fats. While these resources provide an important transitional solution, they are inherently constrained in scale and often rely on international supply chains, including significant imports. This has raised concerns about long-term scalability and energy security.
Alternative approaches such as power-to-liquid synthetic fuels, often referred to as e-fuels, have also been explored. However, these pathways are increasingly challenged by high electricity prices and the enormous energy requirements associated with converting renewable power into liquid hydrocarbons at scale.
Circularity Fuels positions agricultural biogas as a fundamentally different feedstock—one that is both abundant and underutilized. Biogas generated from agricultural waste, particularly dairy manure, is often vented or flared, releasing methane into the atmosphere despite its energy potential. Methane is a highly potent greenhouse gas, and capturing it for fuel production represents both an environmental and economic opportunity.
Turning Dairy Waste into Jet Fuel
The company’s pilot project was conducted at a large dairy operation in California’s Central Valley, housing more than 5,000 cattle. The facility produces significant volumes of biogas from manure digestion, but much of it is currently released or underutilized due to the lack of cost-effective capture and upgrading infrastructure.
Circularity Fuels deployed its integrated conversion system directly on-site, processing raw biogas composed of approximately 65% methane and 35% carbon dioxide. Over the course of thousands of operating hours, the system continuously converted this untreated gas stream into finished liquid hydrocarbons suitable for refining into jet fuel.
At the core of the system are two proprietary reactor technologies. The first is the electrified Ouro bi-reforming reactor, which processes raw biogas in a single step. This unit achieves high conversion efficiency by simultaneously converting both methane and carbon dioxide into synthesis gas. The second component is the Aion Fischer-Tropsch synthesis reactor, which converts the syngas into long-chain hydrocarbons that can be refined into jet fuel.
Both systems are designed as modular, skid-mounted units, enabling deployment at distributed agricultural sites rather than requiring large centralized industrial facilities. This modularity is central to Circularity’s strategy, as biogas resources are typically scattered across thousands of farms rather than concentrated in industrial hubs.
High Conversion Efficiency and Carbon-Negative Potential
One of the key technical achievements highlighted in the pilot is the system’s efficiency in handling carbon dioxide-rich feedstocks. Historically, the high CO₂ content of raw biogas has been a major barrier to economically viable fuel conversion, often requiring costly pre-treatment or separation processes.
Circularity’s Ouro reactor reportedly achieved more than 98% methane conversion and over 90% carbon dioxide conversion in a single electrified step. This level of performance enables direct use of untreated biogas, eliminating several costly preprocessing stages common in traditional SAF production pathways.
The resulting fuel can be blended up to 50% with conventional Jet-A fuel and used in existing commercial aircraft without modifications, in accordance with ASTM D7566 specifications.
Beyond technical feasibility, Circularity Fuels emphasizes the environmental profile of the fuel. Based on internal life-cycle analysis aligned with California’s carbon accounting framework, the SAF produced in the pilot demonstrates a carbon intensity of approximately -350.7 grams of CO₂ equivalent per megajoule. This places it firmly in the category of carbon-negative fuels.
The negative carbon intensity is primarily attributed to methane avoidance. When dairy-derived biogas is not captured, methane is released directly into the atmosphere, where it has a significantly higher global warming potential than carbon dioxide. By capturing and converting this methane into fuel, the system effectively prevents these emissions while displacing fossil jet fuel consumption.
According to the company’s estimates, each gallon of fuel produced in this process has a climate impact equivalent to removing roughly 100 pounds of CO₂ from the atmosphere when accounting for avoided methane emissions.
Economic Implications and Industry Impact
Circularity Fuels argues that its approach could fundamentally reshape the economics of SAF production. By eliminating expensive gas cleanup infrastructure and leveraging widely available agricultural waste streams, the company believes it can achieve cost parity with fossil jet fuel at scale.
The company also highlights that biogas-based SAF qualifies for several regulatory incentive frameworks, including the U.S. Renewable Fuel Standard (RFS) and California’s Low Carbon Fuel Standard (LCFS). These programs provide credits for low-carbon fuels and have historically played a critical role in scaling other renewable fuels such as ethanol, biodiesel, and renewable natural gas.
By stacking these incentives with lower production costs, Circularity Fuels believes SAF derived from biogas can become commercially competitive even in early deployment phases.
Industry observers note that SAF expansion has often been constrained not only by technology but also by feedstock availability and high capital expenditures. Circularity’s distributed model—placing production units directly at the source of waste methane—represents a departure from centralized refinery-scale SAF plants.
Industry Perspectives
The pilot has drawn attention from stakeholders in both the energy and agricultural sectors. Experts in biogas development have long highlighted the challenge of monetizing methane emissions from farms due to the high cost of purification and pipeline transport.
“For decades, dairy operators have flared or vented biogas because the economics of capture and cleanup rarely worked without major infrastructure nearby,” noted Craig Hartman, a veteran biogas project developer. “What Circularity has demonstrated is that you can take raw digester gas and convert it directly into a valuable liquid fuel on-site. That changes the equation for agricultural methane utilization.”
Circularity Fuels leadership has also emphasized that the pilot moves the technology beyond laboratory validation into continuous real-world operation. According to Dr. Stephen Beaton, Founder and CEO of Circularity Fuels, the key milestone was proving that the process can run reliably on actual feedstock under real operating conditions.
“The challenge was never proving that SAF chemistry works,” he said. “It was proving you could do it continuously, on real biogas, at a cost that makes commercial sense. This pilot demonstrates that the full system works end-to-end and can be economically viable at scale.”
Path to Commercial Deployment
With the pilot phase completed, Circularity Fuels is now preparing for its first commercial-scale deployment. The company expects to begin construction of its inaugural commercial facility in 2027, with a focus on regions rich in agricultural biogas resources.
Target markets include large dairy-producing regions in the United States, as well as agricultural hubs in Latin America and Europe. These regions collectively generate significant volumes of methane-rich waste that is often underutilized or released into the atmosphere.
If successfully scaled, the company’s approach could create a distributed SAF production network anchored directly at agricultural waste sources, reducing reliance on imported feedstocks and long-haul fuel logistics.
As the aviation industry continues its search for scalable decarbonization solutions, Circularity Fuels’ pilot marks an important step in demonstrating that waste methane—long considered an environmental liability—may also represent one of the most promising pathways toward carbon-negative aviation fuel.
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