In a major leap for sustainable aviation and agricultural waste management, a US company has achieved the world’s first end-to-end conversion of raw cow manure biogas directly into drop-in jet fuel. This breakthrough could significantly boost the availability of sustainable aviation fuel (SAF) while turning farm waste into a valuable resource.
Groundbreaking Pilot Project in California
Circularity Fuels, a California-based renewable fuels startup, completed a six-month pilot project at a dairy farm near Madera, California. The farm houses over 5,000 cattle and already operates a manure digester that produces biogas (roughly 65% methane and 35% carbon dioxide).
What makes this achievement unique is that the system used untreated, raw biogas straight from the digester — without any prior carbon dioxide removal or extensive cleaning. Using its proprietary modular technology, including the electrified Ouro bi-reforming reactor and the compact Aion Fischer-Tropsch synthesis reactor, the company produced finished jet fuel that meets strict ASTM D7566 Annex A1 (FT-SPK) specifications.
This fuel can be blended up to 50% with conventional Jet-A fuel, making it fully compatible with existing aircraft engines and infrastructure.
Key Technical Achievements
The pilot delivered impressive results:
- Methane conversion rates above 98%
- Carbon dioxide conversion rates exceeding 90%
- Continuous operation for thousands of hours using real farm feedstock
The modular, skid-mounted design allows the entire system to be deployed directly at biogas production sites, eliminating the need for costly gas cleanup infrastructure or long-distance pipelines. This makes it particularly suitable for the scattered, small-to-medium scale nature of dairy farm biogas operations.
Economic and Environmental Benefits
Traditional SAF production often depends on limited feedstocks like used cooking oil, which can only meet a tiny fraction of global aviation demand. By tapping into abundant agricultural biogas — much of which is currently vented or flared — Circularity Fuels offers a lower-cost and more scalable alternative.
The company estimates that future commercial plants could be built at roughly one-fifth the capital cost of comparable European facilities (under $100,000 per barrel-per-day capacity). This could help make SAF prices competitive with fossil jet fuel while creating an additional revenue stream for dairy farmers.
Environmentally, the process shows strong carbon-negative potential. Life-cycle analysis under California’s framework estimates a carbon intensity of -350.7 gCO₂e/MJ. By capturing and converting methane — a greenhouse gas far more potent than CO₂ in the short term — each gallon of this fuel effectively helps remove significant emissions from the atmosphere.
Future Plans and Broader Impact
Backed by funding and awards from ARPA-E, NSF, and the California Energy Commission, Circularity Fuels plans to break ground on its first commercial facility in 2027. Initial focus will be on US dairy regions, with future expansion into Latin America and Europe.
Dr. Stephen Beaton, Founder and CEO (a former Lab Chief at the U.S. Air Force Petroleum Office), highlighted the significance: “The hard part was proving you could do it continuously, from real biogas, at a cost that pencils.”
Experts believe this on-site conversion technology could transform the economics of biogas projects for dairy operators, who have often struggled to find profitable uses for the methane they produce.
Why This Matters for Aviation and Agriculture
Aviation faces intense pressure to reduce emissions, with governments and airlines pushing for higher SAF blends. Technologies like this address critical bottlenecks — feedstock availability, high production costs, and infrastructure needs — while supporting rural economies.
By turning cow manure into jet fuel, the innovation closes the loop on farm waste, reduces greenhouse gas emissions, and provides a domestically sourced, scalable solution for cleaner skies.
This development signals promising progress toward more sustainable aviation and smarter use of agricultural resources. As commercial deployment approaches, it could play a meaningful role in the global transition to low-carbon fuels.
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