Circularity Fuels Converts Dairy Manure Biogas into Sustainable Jet Fuel
California technology startup Circularity Fuels has successfully converted raw farm digester biogas into certified sustainable aviation fuel (SAF) through a pioneering project conducted on a dairy farm near Madera, California. This six-month pilot project processed raw methane, sourced from over 5,000 head of cattle, into jet fuel that meets international aviation safety standards.
The primary economic barrier for agricultural biogas projects traditionally has been the high carbon dioxide content in raw methane, necessitating expensive cleaning infrastructure. Circularity Fuels bypassed these challenges using a modular, skid-mounted dual-reactor stack. This system processes approximately 65% methane and 35% carbon dioxide, achieving a 98% methane and 90% carbon dioxide conversion rate in a bi-reforming reactor, followed by Fischer-Tropsch synthesis to produce liquid hydrocarbons.
This innovation opens a lucrative revenue stream for producers and reduces capital expenditure associated with SAF production. The modular design of Circularity Fuels can produce commercial-grade SAF at a cost of under $100,000 per barrel-per-day of installed capacity, roughly one-fifth of current industry costs.
Environmental metrics from the on-farm process have drawn significant interest, as the system captures methane emissions that would otherwise enter the atmosphere. The resultant fuel achieves a carbon intensity score of -350.7 gCO2e/MJ. Each gallon of this jet fuel is equivalent to removing 100 pounds of carbon dioxide from the atmosphere, according to corporate models.
The fuel is classified as Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK), allowing commercial airlines to use it in up to 50% blends with conventional fuel. The model qualifies for federal and state renewable fuel subsidies, including the EPA’s Renewable Fuel Standard and California’s Low Carbon Fuel Standard.
Circularity Fuels plans to construct its first commercial-scale processing facilities in 2027, targeting biogas reserves in the U.S., Latin America, and Europe. Thousands of testing hours have validated the technology, paving the way for its broader application.
