The US Federal Aviation Administration (FAA) has approved a new renewable jet fuel, bringing the number of approved aviation biofuels to five.
The newest fuel ‘alcohol to jet synthetic paraffinic kerosene (ATJ-SPK) is derived from isobutanol alcohol, produced from renewable feed stocks such as sugar, corn, or forest wastes, the FAA says.
The FAA, which worked with testing organisation, ASTM International, says the biofuel could ‘reduce greenhouse gas emissions on a life-cycle basis by up to 85 per cent.’
The FAA requires that approved biofuels 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.
Other previously approved fuels include:
- Synthesised iso-paraffins (SIP), which convert sugars into jet fuel
- Hydro-processed esters and fatty acids synthetic paraffinic kerosene (HEFA-SPK), which use fats, oils and greases
- Synthetic paraffinic kerosene (FT-SPK) and synthetic kerosene with aromatics (FT-SKA) made using the Fischer-Tropsch process that converts carbon monoxide and hydrogen gases into liquid hydrocarbons. The Fischer-Tropsch process can convert biomass and fossil resources, such as coal and natural gas, into liquid fuels.
With the price of oil low, biofuels are not currently in widespread use, but airlines, including Lufthansa, KLM and Jetstar have been making occasional passenger-carrying bio-fuelled demonstration flights since 2011.