The United States has marked a new milestone in bioenergy and sustainable aviation by completing what is being described as the world’s first end-to-end conversion of raw cow manure biogas into sustainable aviation fuel (SAF), opening a potential new route for lower-emission air transport.
California-based startup Circularity Fuels announced that it successfully completed a six-month pilot project that transformed agricultural biogas from a dairy farm into jet fuel meeting ASTM standards for commercial aviation, Interesting Engineering reported.
The demonstration was carried out at a dairy farm near Madera, California, which houses more than 5,000 cattle and generates biogas through manure digesters.
According to the company, the pilot continuously processed untreated agricultural biogas containing approximately 65 per cent methane and 35 per cent carbon dioxide for thousands of operating hours and converted it into finished aviation fuel.
The resulting sustainable aviation fuel can be blended with conventional Jet-A fuel at concentrations of up to 50 per cent.
Circularity said the breakthrough could improve the economics of SAF production. The company estimates that future commercial plants using its technology could be built at roughly one-fifth of the cost of similar facilities currently under development in Europe.
The technology converts agricultural waste into bioenergy directly at the source through a two-stage process. An electrified bi-reforming reactor first converts raw biogas into synthesis gas, which is then processed through a compact Fischer–Tropsch reactor to produce liquid hydrocarbons suitable for aviation fuel.
During testing, the company reported methane conversion rates above 98 per cent and carbon dioxide conversion rates exceeding 90 per cent.
Global supply of sustainable aviation fuel currently remains limited, accounting for less than one per cent of overall demand. Most existing SAF production relies on used cooking oil, while alternative pathways such as power-to-liquid fuels continue to face cost challenges.
Circularity believes agricultural biogas can offer a more scalable and economically viable solution.
The company estimates that commercial facilities could be developed at less than $100,000 per barrel per day of installed capacity, creating the possibility for dairy-based SAF to compete more directly with conventional jet fuel.
Dr. Stephen Beaton, Founder and Chief Executive Officer of Circularity Fuels, said the challenge was not designing a concept but demonstrating continuous production using real agricultural feedstock under practical conditions.
The company also highlighted the environmental potential of the approach. Internal lifecycle analysis indicates the fuel could achieve a carbon intensity score of negative 350.7 grams of carbon dioxide equivalent per megajoule under California’s regulatory framework, largely due to capturing methane that would otherwise enter the atmosphere.
Industry observers noted that dairy operations have historically had limited options to generate value from raw biogas without costly gas-cleaning infrastructure.
Following the pilot’s completion, Circularity Fuels plans to begin construction of its first commercial-scale facility in 2027 and is evaluating expansion opportunities across dairy and agricultural regions in the United States, as well as Latin America and Europe.
