Technical standards organisation ASTM International has approved a new alternative environmentally friendly, bio-based jet fuel, known as alcohol to jet synthetic paraffinic kerosene (ATJ-SPK).

Supported by the US Federal Aviation Administration (FAA), the recent approval has brought the total number of these approved products for use in air travel to five.

Compared with the conventional petroleum-based fuels, ATJ-SPK expects to make air travel more environmentally sustainable and help to reduce air quality emissions.

FAA noted that it approves new renewable jet fuel pathways through ASTM International and the agency’s emissions and noise (CLEEN) collaboration with the aviation industry played a vital role in ATJ-SPK.

A renewable product, ATJ-SPK is created from an alcohol called isobutanol that is derived from renewable feed stocks, including sugar, corn or forest waste.

Previously approved renewable fuels are synthesised iso-parafins (SIP), hydro-processed esters and fatty acids synthetic paraffinic kerosene (HEFA-SPK), Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) and Fischer-Tropsch synthetic kerosene with aromatics (FT-SKA).

SIP converts sugars into jet fuel; HEFA-SPK uses fats, oils and greases; FT-SPK and FT-SKA use several 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, including coal and natural gas.

The alternative fuels are expected to help the aviation industry to meet its climate change goal of carbon neutral growth.

"ATJ-SPK expects to make air travel more environmentally sustainable and help to reduce air quality emissions."

ATJ-SPK is said to reduce greenhouse gas emissions on a lifecycle basis by up to 85%.

The alternative jet fuels are considered to have the potential to be increasingly viable for cost-competitive production and extensive use.

While fulfilling cost-saving aim of the aviation industry, the FAA intends to support developing ways to use the alternative fuels directly in existing aircraft without making any change to engines or other equipment while maintaining an equivalent level of safety and performance to petroleum jet fuels.

Additionally, 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 centre (ASCENT), a consortium of research universities.

Last month, the FAA selected two unleaded fuel formulations from Shell and Swift Fuels for further testing, as part of its current efforts to develop an acceptable unleaded fuel for small airplanes.

The testing is scheduled to begin this year and end in 2018.