Sustainable Aviation Fuel Glossary

AFOLU – Agriculture, forestry, and other land use

AIC Aviation-induced cloudiness

Alternative jet fuel – another term for SAF, that was used before SAF became the standard industry term

ATSM Annex – see ATSM Spec

ASTM International – formerly the American Society for Testing and Materials, is an international standards organization. Its Subcommittee D02.J0 on Aviation Fuels guides the standards for aviation fuel. Originally founded in 1898 to work out why railway tracks were breaking.

ASTM spec: D165 – the technical certification for SAF produced from co-processing fats, oils and greases (FOG)

ASTM spec: D7566-1 – Annex 1 – the technical certification for SAF produced using Fischer-Tropsch process. Limited to 50% blend.

ASTM spec: D7566-2 – Annex 2 -the technical certification for SAF produced from HEFA (recycled oils and fats). Limited to 50% blend.

ASTM spec: D7566-3 – Annex 3 – the technical certification for SAF produced from biomass used for sugar production. Limited to 10% blend

ASTM spec: D7566-4 – Annex 4 – the technical certification for SAF made from aromatics from alkylation (such as coal, biomass, natural gas). Limited to 50% blend.

ASTM spec: D7566-5 – Annex 5 – the technical certification for Alcohol to Jet (AtJ) pathway. Maximum blend is 50%

ASTM spec: D7566 –6 – Annex 6 – covers Catalytic Hydrothermolysis – such as soybean oil, jatropha oil, camelina oil, tung oil. Maximum blend in 50%

 ASTM spec: D7566 –7 – Annex 7 – the technical certification for SAF produced from algae. Limited to 10% blend.

 Alcohol to Jet  – Converting alcohols into SAF by removing the oxygen and linking the molecules together to get the desired carbon chain length (i.e. oligomerization). Feedstock ethanol and iso-butanol. Maximum blend ratio is 50%.

ATAG – Air Transport Action Group

 ATJ – Alcohol to jet

ATJ-SAF – Alcohol to Jet Sustainable Aviation Fuel

ATJ-SPK Alcohol to Jet Synthetic Paraffinic Kerosene and the pathway to produce it

ATS – Aviation Transition Strategy

BAU – Business as Usual

BECCS – Bioenergy with carbon capture and storage

Bio-diesel – Diesel made from sustainable feedstocks

Bio-jet/Bio-jet fuel – another term for SAF, that was used before SAF became the standard industry term

 Bio-kerosene – another term for SAF, that was used before SAF became the standard industry term

CAGR Compound annual growth rate

Catalytic Hydrothermolysis (CHJ) – CHJ converts fatty acid esters and free fatty acids into SAF via catalytic hydrothemolysis followed by any combination of hydrotreatment, hydrocracking, or hydroisomerization and fractionation. Max blend ratio is: ASTM spec: 50%. D7566 – Annex 6.

CCUS – Carbon capture, utilisation, and storage CDR Carbon dioxide removals

CHJ – Catalytic Hydrothermolysis Jet Fuel – a type of SAF

CH-SAF – Catalytic Hydrothermolysis SAF – – a type of SAF

CH-SK – Catalytic Hydrothermolysis Synthesized Kerosene –  a type of SAF

Commercial Aviation Alternative Fuels Initiative (CAAFI)

CO2 – Carbon dioxide

CO2e – Carbon dioxide equivalent

Co-processing: Vegetable oils, waste oils and fats, or FT-wax is, can be processed along with conventional crude oil feedstocks in existing refining complexes. ATSM D1655 covers SAFco-processing from fats, oils and greases

Corn stover – The leaves, stalks, and cobs of maize (corn) plants that are left in fields after cobs are harvested.SAF from corn stover is seen as a second generation feedstock as it made from waster unlike conventional corn ethanol.

CORSIA – Carbon Offsetting and Reduction Scheme for International Aviation

CST Clean Skies for Tomorrow initiative

DAC – Direct Air Capture

DACCS – Direct air carbon capture and storage

DOE – The US Department of Energy

Feedstock – the raw ingredients used to make SAF. Such as used cooking oil, forestry waste etc.

Fit for 55 – European Union legislation that aims to reduce greenhouse gas emissions by 55% by 2030.

FOG – Fats, oils and greases

Fischer Tropsch – In 1925 Franz Fischer and Hans Tropsch at the Kaiser Wilhelm Institute for Coal Research in Mülheim an der Ruhr, Germany, developed a process to convert a mixture of carbon monoxide and hydrogen (syngas) into liquid hydrocarbons. The process needs catalysts, high temperatures and high pressure.

FT – Fischer Tropsch

FT-SPK – Fischer Tropsch Synthetic Paraffinic Kerosene – SAF produced using the Fischer Tropsch process

FT-SKA – Fischer Tropsch Synthetic Kerosene with Aromatics – SAF produced using the Fischer Tropsch process containing aromatics

GHG – Greenhouse gas

HEFA – Hydroprocessed esters and fatty acids – used to describe both the oils and fats used as feedstock and the pathway of making it.

HEFA-SAF – SAF made from Hydroprocessed esters and fatty acids

HEFA-SPK – Synthetic paraffinic kerosene (SAF) made from hydroprocessed esters and fatty acids synthetic paraffinic kerosene

HFS-SIP – see Synthesized Iso-Paraffins (SIP)

HHC-SPK – Hydroprocessed Hydrocarbons – Synthetic Paraffinic Kerosene

Hydrotreating – When oils and fats (triglycerides) are reacted hydrogen to remove oxygen. The remaining hydrocarbon chains are similar to diesel and then can then be split into SAF.

HVO – Hydrotreated Vegetable Oil – used interchangeably with HEFA in the bio-fuel industry, but more associated with bio diesel rather than SAF.

IATA International Air Transport Association

ICAO International Civil Aviation Organization

IEA International Energy Agency

IPCC Intergovernmental Panel on Climate Change

ICCT International Council on Clean Transportation

Jet A/Jet-A – commercial jet fuel grade commonly used in North America (-40oC/-40oF freeze point).

Jet A1/Jet A-1 – jet fuel grade commonly used in Canada and outside of North America (-47oC/-52.6oF freeze point).

LCOE – Levelised cost of renewable electricity

Lignocellulose – plantmatter  or biomass – also called lignocellulosic biomass.

LTAG – Long-term aspirational goal

LTO – Landing and takeoff

Maximum blend – the maximum amount of SAF that can be used when mixed with fossil jet fuel. Governed by ASTM regulations.

Methanol-to-Jet (MTJ) – SAF that is produced from methanol. Not yet an approved pathway but one that is being worked on. 

MSW – Municipal Solid Waste

MTJ – Methanol-to-Jet. SAF that is produced from methanol. Not yet an approved pathway but one that is being worked on. 

Neat SAF – SAF that has not been blended with fossil fuel like Jet A1/Jet A-1

Non-conventional jet fuel – another term for SAF, that was used before SAF became the standard industry term

NOX – Nitrogen oxides

Oligomerization – Creating oligomers. An Oligomer is a molecule made of a few repeating units.

PTL – Power to liquid

Renewable jet fuel – another term for SAF, that was used before SAF became the standard industry term

Roundtable on Sustainable Biomaterials (RSB) – the RSB has members from a worldwide movement of businesses, NGOs, academics, government and UN organisations want to support and develop best practices for all biomaterials.

RSB -Roundtable on Sustainable Biomaterials)

SAF – Sustainable Aviation Fuel

SBTi – Science Based Targets Initiative – a partnership between CDP (formerly Carbon Disclosure Project), United Nations Global Compact, WRI (World Resources Institute) and WWF (World Wildlife Fund). 

SIPSynthesized Iso-Paraffins

SBC – Synthetic blend component  – SAF produced in a standalone unit (as opposed to co-processing)

SPDSynthetic Paraffinic Diesel

Syngas – a mixture of carbon monoxide and hydrogen used in the Fischer-Tropsch process

Synthesized kerosene – SAF produced in a standalone unit (as opposed to co-processing)

Synthetic Paraffinic Kerosene (SPK) – another term for SAF, that was used before SAF became the standard industry term

UNFCCC – United Nations Framework Convention on Climate Change

Well-to-tank – covers Scope 3 emissions from jet fuel

Well-to-wake – covers full value chain