The FAA said it has played an integral role in developing and the bio-based jet fuel, bringing the total number of these approved products for use in air travel to five.
In collaboration with the aviation industry, the FAA approves new renewable jet fuel pathways through ASTM International. The FAA’s Continuous Lower Energy, Emissions and Noise (CLEEN) partnership with industry was crucial in completing the necessary steps to support ASTM International approval of this new fuel, known as Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK). It is created from an alcohol called isobutanol that is derived from renewable feed stocks such as sugar, corn or forest wastes.
Other previously approved fuels include:
- Synthesized Iso-parafins (SIP) which convert sugars into jet fuel.
- Hydro-processed Esters and Fatty Acids Synthetic Paraffinic Kerosene (HEFA-SPK), which use fats, oils and greases.
- Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK) and Fischer-Tropsch Synthetic Kerosene with Aromatics (FT-SKA). Both fuels use various sources of renewable biomass such as municipal solid waste, agricultural wastes and forest wastes, wood and energy crops. These fuels can also be made from fossil resources such as coal and natural gas.
These new fuels will help the aviation industry meet its climate change goal of carbon neutral growth. For example, operation with ATJ-SPK could reduce greenhouse gas emissions on a life-cycle basis by up to 85 percent.
As more alternative jet fuels are developed, these products have the potential to be increasingly viable for cost-competitive production and broad use. Another cost-saving goal and FAA focus area is a “drop-in” requirement for alternative fuels. That means the fuels can be used directly in existing aircraft without any modification to engines or other equipment while maintaining an equivalent level of safety and performance to petroleum jet fuels.
In addition to CLEEN, the FAA is working with industry, other government agencies and academia through the Commercial Aviation Alternative Fuels Initiative (CAAFI) and the agency’s Aviation Sustainability Center (ASCENT), a consortium of research universities.