Glossary

Below is a list of terms and definitions in alphabetical order. Click a letter to jump to that section:

A B C D E F G H I J L K M N O P Q R S T U V W X Y Z

A

Term/Acronym Entity/Meaning Definition/Context
A4A Airlines for America A4A is an airline trade organization that advocates on behalf of its members to shape policies and measures that promote safety, security, and a healthy U.S. airline industry.
ABFA Advanced Biofuels Association ABFA is an industry trade organization representing entities pursuing the commercialization of renewable fuels.
ACI-NA Airports Council International - North America ACI-NA is a trade organization that represents local, regional, and state governing bodies that own and operate commercial airports in the United States and Canada. ACI-NA is one of the five worldwide regions of Airports Council International (ACI).
ACRP Airport Cooperative Research Program A research effort of the Transportation Research Board (TRB) that carries out applied research on problems shared by airport operating agencies. The TRB is an entity of the National Academies of Sciences, Engineering, and Medicine.
AEE Association of Energy Engineers Association of Energy Engineers (AEE) is a nonprofit professional society of over 11,000 members in 78 countries. The mission of AEE is “to promote the scientific and educational interests of those engaged in the energy industry and to foster action for Sustainable Development.” AEE also commonly refers to FAA AEE.
AFRL Air Force Research Laboratory An organization of the United States Air Force dedicated to the discovery, development, and integration of war fighting technologies for our air, space, and cyberspace forces. AFRL has been engaged in the evaluation and qualification of synthetic jet fuel production methodologies.
AIA Aerospace Industries Association The Aerospace Industries Association (AIA) is the trade association representing the nation's aerospace and defense manufacturers.
ALTA Latin America & Caribbean Air Transport Association (Asociación Latinoamericana y del Caribe de Transporte Aéreo) ALTA is a private law entity nonprofit comprised of airlines in Latin America and the Caribbean, which aims to combine and coordinate the efforts of its members to facilitate the development of air transport in Latin America and strengthen the channels of collaboration and communication between those for mutual benefit of industry and its users.
Alternative Fuels Typically, a fuel produced from sources other than petroleum The Energy Policy Act of 1992 defines alternative fuels as methanol, denatured ethanol, and other alcohol; mixtures containing 85 percent or more (but not less than 70 percent as determined by the Secretary of Energy by rule to provide for requirements relating to cold start, safety, or vehicle functions) by volume of methanol, denatured ethanol, and other alcohols with gasoline or other fuels. Includes compressed natural gas, liquid petroleum gas, hydrogen, coal-derived liquid fuels, fuels other than alcohols derived from biological materials, electricity, or any other fuel the Secretary of Energy determines by rule is substantially not petroleum and would yield substantial energy security and environmental benefits.
AJF Alternative Jet Fuel This term is broader than SAF as it includes fuels sourced from petroleum alternatives that may not be considered sustainable, such as coal.
Animal Oils   Fats and Oils derived from animal processing, being used for conversion into fuels, including: tallow - from beef, sheep, goat processing white grease/lard - from pork processing fish oil, shellfish oil, chicken fat
AOPL Association of Oil Pipelines A United States based nonprofit organization whose membership is comprised of owners and operators of liquid pipelines.
API American Petroleum Institute API is a national trade association that represents all aspects of the United States' oil and natural gas industry.
APR Aqueous Phase Reforming A reforming reaction that occurs in the presence of liquid water; specifically a reforming reaction to generate hydrogen and alkanes from biomass-derived carbohydrates.
ARPA-E Advance Research Projects Agency - Energy An entity within the Department of Energy that advances high-potential, high-impact energy technologies that are too early for private-sector investment. ARPA-E projects have the potential to radically improve U.S. economic security, national security, and environmental well-being. ARPA-E empowers America's energy researchers with funding, technical assistance, and market readiness.
ASCENT FAA Center of Excellence for Alternative Jet Fuels & Environment A research partnership with cost-sharing among academia, industry, and government, focused on environmental aviation topics and alternative jet fuel.
ASTM ASTM International ASTM International, originally known as the American Society for Testing and Materials (ASTM), is a voluntary standards development organizations. ASTM International specifications are used for the certification of jet fuel.
ASTM D1655 Standard Specification for Aviation Turbine Fuels A widely utilized specification that defines the properties of aviation turbine fuel for civil use and describes fuels found satisfactory for the certification and operation of aircraft and engines. The specification can be used as a standard in describing the quality of aviation turbine fuels from the refinery to the aircraft.
ASTM D4054 Standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives This practice covers and provides a framework for the qualification and approval of new fuels and new fuel additives for use in commercial and military aviation gas turbine engines. The practice was developed as a guide (e.g. for those seeking ASTM D7566 adoption of a new synthetic jet fuel blending component) by the aviation gas-turbine engine Original Equipment Manufacturers (OEMs) with ASTM International member support.
ASTM D7566 Standard Specification for Aviation Turbine Fuels Containing Synthesized Hydrocarbons This specification defines specific types of aviation turbine fuel that contain synthesized hydrocarbons for civil use in the operation and certification of aircraft and describes fuels found satisfactory for the operation of aircraft and engines.
ATA Air Transport Association of America Previous name of A4A
ATJ, ATJ-SPK Alcohol-to-Jet, Alcohol-to-Jet Synthetic Paraffinic Kerosene A synthetic jet fuel blending component produced from the conversion of alcohols to hydrocarbon chains (in the jet fuel range) through the use of thermo-chemical processes (dehydration, oligomerization, hydrogenation, and fractionation primarily)

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B

Term/Acronym Entity/Meaning Definition/Context
Bioenergy   Bioenergy is a form of energy that comes from materials derived from recently living biological organisms (biomass), including plants, animals, and their byproducts.
Biofuel   Renewable fuels derived from biological materials that can be regenerated. This distinguishes them from fossil fuels, which are considered non-renewable. Examples of biofuels are fermented alcohols, biodiesel, renewable diesel, RJF/SAF, and biogas. Biofuels compatible with jet-powered aviation are described in ASTM D7566. Renewable fuels can be produced from a wide range of non-petrochemical feedstocks, and via a wide range of conversion processes, including both biochemical and thermochemical processes.
Biomass   Biomass is a general term that describes any material (mass) that has been produced by the growth and resource use of living organisms. Therefore, any plant, animal, or bacterial material is biomass.
BOE Barrel of Oil Equivalent A term used to summarize the amount of energy that is equivalent to the amount of energy found in a barrel of crude oil. Also known as Crude Oil Equivalent (COE).
BRDB, BRDB TAC, BRDI Biomass Research & Development Board; BRDB Technical Advisory Committee; Biomass Research & Development Initiative The Biomass Research and Development Board is an interagency collaborative effort among the White House Office of Science and Technology Policy and other agencies involved in biomass research and development. The Board, which “coordinates research and development activities concerning bio-based fuels, products, and power across federal agencies,” is co-chaired by the USDA and the U.S. Department of Energy. The BRDB has a Technical Advisory Committee whose role it is to provide feedback to the chairs on the overall effectiveness of the program.
BTL Biomass to Liquid The process to produce liquid biofuels from biomass, or more specifically, referring to a process via which biomass is gasified and converted to liquid fuels via Fischer-Tropsch methods.

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C

Term/Acronym Entity/Meaning Definition/Context
Csoot, C-soot, Carbon soot, black carbon Soot particles, typically airborne Unburned carbon molecules. See also UHC.
CAAFI Commercial Aviation Alternative Fuels Initiative A coalition of airlines, aircraft and engine manufacturers, energy producers, researchers, international participants, and U.S. government agencies. Together these stakeholders are leading the development and deployment of alternative jet fuels for commercial aviation.
Carbon Neutral Growth   An industry, sector, or company continuing to expand its activities without incurring further increases in net greenhouse gas emission
Catalysis   The process in which the rate of a chemical reaction is either increased or decreased by means of a chemical substance.
Catalyst   A substance that increases the rate of a chemical reaction without itself undergoing any change.
CBTL Coal/Biomass to Liquids The process to produce liquid biofuels from a combination of coal and biomass, or more specifically, a process via which coal and biomass are gasified and converted to liquid fuels via Fischer-Tropsch methods
CCS Carbon Capture and Sequestration/Storage A process of capturing carbon dioxide emissions to prevent them from going into the atmosphere, and then storing them permanently. A commonly discussed strategy is to store captured CO2 by pumping it underground into geological formations. There are also discussion of biological capture and sequestration in trees, algae, etc.
CCU; CCSU Carbon Capture and Use; Carbon Capture Storage and Use The process via which captured carbon is subsequently re-used and released into the atmosphere, representing at least one additional recycling of the carbon.
Cellulose   The structural component of the primary cell wall of green plants, many forms of algae, and the oomycetes. It is made up of cross-linked sugar molecules and is difficult to break down. A “cellulosic” biofuel production process would degrade cellulose sufficiently to make the sugars accessible for further processing.
Certification   Refers to the confirmation of certain characteristics of an object, person, or organization. In the realm of fuels, it often refers to whether a fuel can be “certified” as meeting a specification.
CH Catalytic Hydrothermolysis A process using hot, compressed water and a catalyst to convert vegetable and animal fats from triglycerides into a bio-crude intermediate that can then be refined to produce a complete drop-in alternative jet fuel including aromatic compounds.
CH4 (CH4, or CH4) Methane Methane (CH4) is a naturally occurring gas emitted from a variety of natural and human-influenced sources. It is both a source of energy (natural gas) and a potent greenhouse gas. It is naturally emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste (e.g. in municipal solid waste landfills). As a greenhouse gas, methane remains in the atmosphere for approximately 9-15 years. Methane is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide (CO2) over a 100-year period. Human-influenced sources include landfills, natural gas and petroleum systems, agricultural activities, coal mining, stationary and mobile combustion, wastewater treatment, and certain industrial processes.
CLEEN Continuous Lower Energy Emissions and Noise An FAA Program to develop and foster industry acceptance of new technologies that reduce environmental impacts
CNG Compressed Natural Gas Natural gas (consisting primarily of methane) that is compressed until it is less than 1% of its volume at standard atmosphere. It can serve as an alternative to gasoline, and its use is often targeted at fleet vehicles (trucks and buses). It typically is drawn from domestically drilled natural gas wells or in conjunction with crude oil production, although it can be comprised of biogas as well.
CO Carbon Monoxide Carbon Monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air, and is toxic to humans when encountered in concentrations above about 35 ppm. Carbon Monoxide is produced from the partial oxidation of carbon-containing compounds; it forms when there is not enough oxygen to complete the combustion of carbon (which produces carbon dioxide (CO2) and water). CO has a role in the formation of ground-level ozone, and so its production (e.g. from jet engines) is regulated.
CO2 (CO2, CO2) Carbon Dioxide A natural product of the combustion of carbon compounds. Enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., manufacture of cement). Carbon dioxide is also removed from the atmosphere (or “sequestered”) when it is absorbed by plants or the ocean as part of the biological carbon cycle.
COE Crude Oil Equivalent A term used to summarize the amount of energy that is equivalent to the amount of energy found in a barrel of crude oil. Also known as Barrel of Oil Equivalent (BOE).
Commercial Aviation   A sector of the U.S. economy comprising scheduled and nonscheduled passenger and cargo airlines, aviation manufacturers, airport and aircraft service providers (including government services), and air cargo service providers.
Consortium   An association or a combination, as of businesses, financial institutions, or investors, for the purpose of engaging in a joint venture.
Crack Spread   The difference between crude oil and refined petroleum product prices, when expressed in similar units, is known as the crack spread. For example, if crude oil costs $60 per barrel and jet fuel costs $75 per barrel, the jet fuel crack spread is $15 per barrel.
Cracking (of fuel)   Term used in the oil refining industry, meaning to “crack” crude oil, which is to break down the long-chain hydrocarbons in the crude oil into shorter chains. Also used with regard to the breaking of long-chain fatty acid derivatives (usually C18-C22) or synthetic waxes (e.g., from Fischer-Tropsch) to the jet fuel range (C8-C14).
Crude Oil   A mixture of hydrocarbons that exists in the liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure after passing through surface-separating facilities. The U.S. benchmark for crude oil prices is West Texas Intermediate (WTI), measured in Cushing, Oklahoma.
CTL Coal to Liquid The process to produce liquid biofuels from coal, or more specifically, referring to a process via which coal is gasified to form a syngas which is then converted to liquid fuels via Fischer-Tropsch methods.

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D

Term/Acronym Entity/Meaning Definition/Context
DARPA Defense Advanced Research Program Agency The research and development office for the U.S. Department of Defense.
Deployment   Commercialization and commercial use of a new technology such as alternative fuels.
DLA-Energy Defense Logistics Agency Energy An agency within the Department of Defense responsible for providing the Department of Defense and other government agencies with comprehensive energy solutions in the most effective and efficient manner possible. DLA procures fuel for the Armed Services.
dLUC Direct Land Use Change A change in the use or management of land by humans. The Intergovernmental Panel on Climate Change (IPCC) distinguishes six broad land use categories: forestland, cropland, grassland, wetlands, settlements, and other land (e.g. bare soil, rock and ice), where the conversion from one land use category to another is called LUC.
DOD Department of Defense The U.S. Department of Defense is the federal department charged with coordinating and supervising all agencies and functions of the government relating directly to national security and the military.
DOE Department of Energy The U.S. Department of Energy is the federal department charged with advancing the development of energy technologies and promoting related innovation in the United States.
DOT Department of Transportation The mission of the U.S. Department of Transportation is to develop and coordinate policies that will provide an efficient and economical national transportation system, with due regard for need, the environment, and the national defense.
DPA Defense Production Act U.S. Federal law enacted in 1950 giving the President authority to force private industry into giving priority to defense and homeland security contracts and allocate resources as needed. Title III of the Act enables the Federal government to engage in activities to “create assured, affordable, commercially viable production capabilities and capacities for items essential for national defense.” The Advanced Drop-in Biofuels Production Project under this program is funding several first-of-a-kind drop-in alternative fuel biorefineries. This program is funded jointly by USDA, the Department of Energy, and the Department of Defense.
Drop-in Jet fuel blend   A substitute for conventional jet fuel, that is completely interchangeable and compatible with conventional jet fuel when blended with conventional jet fuel. A drop-in fuel blend does not require adaptation of the aircraft/engine fuel system or the fuel distribution network, and can be used “as is” on currently flying turbine-powered aircraft.

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E

Term/Acronym Entity/Meaning Definition/Context
EIA Energy Information Administration U.S. Department of Energy's Energy Information Administration provides official energy analysis, information and statistics.
EPA Environmental Protection Agency The U.S. Environmental Protection Agency enforces U.S. environmental protection laws.
EtOH Ethanol The molecular formula for Ethanol is C2H5OH. Ethanol is often abbreviated as EtOH, using the common organic chemistry notation of representing the ethyl group (C2H5) with “Et” and the Hydroxyl group with "OH". Ethanol is primarily a product of fermentation processes (the conversion of sugars). Although alcohols are readily combustible, they are not compatible with existing turbine-powered aircraft or infrastructure.

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F

Term/Acronym Entity/Meaning Definition/Context
FAA Federal Aviation Administration The U.S. Federal Aviation Administration is an entity within the Department of Transportation whose continuing mission is to provide the safest, most efficient aerospace system in the world.
FAA AEE FAA's office of Environment and Energy This Office within the FAA recommends and coordinates national aviation policy relating to environmental and energy matters, including noise and emissions. The FAA uses such multi-letter terminology as a convenient organizational naming convention.
FAME Fatty Acid Methyl Ester Fatty Acid Methyl Ester (FAME) is a moniker commonly used in reference to biodiesel. This is traditional biodiesel, produced by processing raw vegetable oil or animal fats through a chemical process called transesterification. FAME is not a suitable “drop-in” fuel for jet aircraft as it contains oxygenates, and in fact, is considered to be a contaminant when found in jet fuel.
Fatty Acids   Organic acids from which fats and oils are made. These can be used as feedstocks for HEFA fuels.
FBO Fixed-Based Operator The primary provider of services to general aviation aircraft and operators located at or adjacent to an airport. General aviation refers to all flights other than military flights: scheduled airline flights and regular cargo flights, both private and commercial.
Feedstock   Raw material(s) required for an industrial process, and more specifically, a source of hydrogen and carbon (hydrocarbon) for the production of an alternative fuel. Feedstocks can come in various forms (solid, gas, liquid) and from various sources (e.g. oils, sugars and starches, cellulose, industrial waste streams).
FERC Federal Energy Regulatory Commission The federal agency with jurisdiction over, among other things, interstate natural gas pricing, oil pipeline rates, and gas pipeline certification
Fermentation   Any of a group of chemical reactions induced by living or nonliving ferments that split complex organic compounds into relatively simple substances (e.g. the conversion of sugars or starches to ethanol and CO2)
Fluorinated Gases   Hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for ozone-depleting substances (i.e., CFCs, HCFCs, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”).
Fossil Fuels   Any naturally occurring organic fuel found in the Earth's crust (such as petroleum, coal, and natural gas) formed by fossilization of organic material deposited by decaying plant/animal matter
FRJ Fermented Renewable Jet A biofuel created by a synthetic biology process in which metabolic processes involved in fermentation have been co-opted by genetically modifying organisms to produce hydrocarbons in place of ethanol
FRL Fuel Readiness Level A scale that provides an objective measure of how close a particular alternative fuel or feedstock is to successful deployment for jet fuel production.
FSA Fuel Supply Agreement A document that contains details on an agreement between a seller and buyer for a commitment to sell and to purchase fuel. The agreement will contain the name of buyer, the seller, term, product specification, volume, price, payment terms, delivery points, contacts, and any other terms and conditions related to the transaction.
Aviation Fuel Supply Model Agreement Version 5 (Effective January 2017)
Guidance for Selling Alternative Fuels to Airlines (June 2013)
FSRL Feedstock Readiness Level The Feedstock Readiness Level (FSRL) Tool is a companion to the CAAFI® Readiness Level (FRL) Tool. The FSRL Tool provides a means of tracking development and availability of the raw materials (or feedstocks) required to make alternative jet fuels. Levels range from 1 (preliminary feedstock evaluation) to 9 (commercial deployment of the feedstock).
FT Fischer-Tropsch Fischer-Tropsch is a catalyzed chemical reaction in which synthesis gas, a mixture of carbon monoxide and hydrogen, is converted into liquid hydrocarbons of various forms. Named for German researchers Franz Fischer and Hans Tropsch.
FT Process   The Fischer-Tropsch process (or Fischer-Tropsch Synthesis) is a catalyzed chemical reaction in which synthesis gas, a mixture of carbon monoxide and hydrogen, is converted into liquid hydrocarbons of various forms via the use of a reactor with cobalt or iron catalyst.
FT-SPK, FT Fuel Synthesized Paraffinic Kerosene produced from the hydroprocessing of Fischer-Tropsch synthesized hydrocarbons Nomenclature for an approved process for the creation of jet fuel blending component using FT conversion of syngas. The specification for this fuel is included in ASTM D7566, Annex A1.
FT-SPK/A Synthesized Paraffinic Kerosene with Aromatics produced from the hydroprocessing of Fischer-Tropsch synthesized hydrocarbons Nomenclature for a pending approval for the creation of jet fuel blending component (paraffins and aromatics) using FT conversion of syngas. The specification for this fuel will be included in ASTM D7566, Annex A4.
Fuel Farm   Holding place where fuel resides

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G

Term/Acronym Entity/Meaning Definition/Context
Gasification   A thermochemical manufacturing process that converts any material containing carbon—such as coal, petroleum coke (petcoke), or biomass—into synthesis gas (syngas)
General Aviation   A term used to describe all non-military and non-airline flying, encompassing everything from recreational aircraft to experimental aircraft to privately owned and operated business jets. General aviation flies according to FAA's part 91 or 135 rules.
GHG Greenhouse Gases Greenhouse Gases trap heat in the atmosphere. The principal greenhouse gases that enter the atmosphere because of human activities are carbon dioxide, methane, nitrous oxide and fluorinated gases.
GWP Global Warming Potential The cumulative radiative forcing effects of a gas over a specified time horizon resulting from the emission of a unit mass of gas relative to a reference gas. Used to compare different greenhouse gases with each other on a relative basis

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H

Term/Acronym Entity/Meaning Definition/Context
H2O Water  
HAPs Hazardous air pollutants  
HDCJ Hydrotreated Depolymerized Cellulosic Jet Pyrolysis process to convert plant biomass into biocrude oil via thermochemical depolymerization, followed by upgrading to jet fuel
HEFA Hydroprocessed Esters and Fatty Acids Product of converting vegetable and animal fats from triglycerides into hydrocarbons via hydrogenation to remove oxygen. Jet fuel production requires subsequent cracking of long hydrocarbons to jet fuel length.
HEFA-SPK Synthesized Paraffinic Kerosene produced from Hydroprocessed Esters and Fatty Acids Nomenclature for an approved process for the creation of jet fuel blending component using hydroprocessing of plant and animal based fats, oils, and greases (mono-, di-, and triglycerides, free fatty acids, and fatty acid esters). The HEFA process converts the oils into hydrocarbons via hydrogenation to essentially remove all oxygen. Jet fuel production requires subsequent hydroprocessing of these hydrocarbons to jet fuel length. The specification for this fuel is included in ASTM D7566, Annex A2.
HFS-SIP Hydroprocessed Fermented Sugars to Synthesized Isoparaffins Nomenclature for an approved process for the creation of jet fuel blending component by using microbial conversion of sugar to hydrocarbons. The process entails the fermentation of sugars into a hydrocarbon molecule using modified yeasts. The existing approved process produces a C15 hydrocarbon molecule called farnesene, which after hydroprocessing to farnesane, can be used as a blendstock in jet fuel up to 10%.
HRJ Hydrotreated Renewable Jet A moniker used to describe HEFA-SPK prior to the name being formalized by ASTM D7566.
Hydrocarbons   Substances containing only hydrogen and carbon. Fossil fuels are comprised of hydrocarbons, as are synthetic drop-in jet fuels.
Hydroprocessing   Any of several chemical engineering processes including hydrogenation, hydrocracking, and hydrotreating, especially as part of oil refining
Hydrotreating   Process that removes sulfur and nitrogen in petroleum refineries to improve the quality of gasoline, jet fuels, and diesel fuel

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I

Term/Acronym Entity/Meaning Definition/Context
IATA International Air Transport Association Industry group operating as a vehicle for inter-airline cooperation in promoting safe, reliable, secure, and economical air services for the benefit of the world's consumers
ICAO International Civil Aviation Organization ICAO is a United Nations specialized agency that works with 191 member states and global aviation organizations to develop international Standards and Recommended Practices which States reference when developing their legally-enforceable national civil aviation regulations.
IEA International Energy Agency Intergovernmental organization which acts as energy policy advisor to 28 member countries in their effort to ensure reliable, affordable, and clean energy for their citizens. Founded during the oil crisis of 1973-74, the IEA's initial role was to co-ordinate measures in times of oil supply emergencies. As energy markets have changed, so has the IEA. Its mandate has broadened to incorporate the “Three Es” of balanced energy policy making: energy security, economic development, and environmental protection.
iLUC Indirect Land Use Change Land Use Change that occurs as the result of a change in demand for a product that causes a change in agricultural production on land not being used for the production of that product. These changes are often driven by market mediated response or policies (e.g., RED or RFS).
ILUC Induced Land Use Change The sum of direct (dLUC) and indirect (iLUC) land use change. Most land use change analysis is conducted with computable general equilibrium (CGE) models or large scale agricultural sector models, and direct and indirect land use changes are not distinguishable in those models. The ILUC occurs as a result of a shock (often policy related) applied to the model, which “induces” market mediated responses.
IPCC Intergovernmental Panel on Climate Change IPCC is a body established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic consequences.

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J

Term/Acronym Entity/Meaning Definition/Context
Jet A, Jet A1 Jet fuel Both Jet A and Jet A1 are kerosene-based fuels used to power turbine-based engines typically found on high-speed commercial aircraft. It is defined by ASTM D1655 specification. Jet A is normally only available in the U.S.A, while Jet A1 is widely used elsewhere. The two fuels differ by requiring different levels of freeze point maximum (-40°C for Jet A, and -47°C for Jet A-1).
Jet Fuel   A generic term that refers to a mixture of hydrocarbons in the C8 to C16 range, consisting of paraffins, cyclo-paraffins, and aromatics. It is a middle distillate fuel with properties that make it conducive to use in turbine (jet) powered aircraft (e.g. high energy density, low freezing point, and high flash point).
Joule   A unit of work or energy symbolized by the letter J

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K

Term/Acronym Entity/Meaning Definition/Context
Kyoto Protocol   The Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on Climate Change. The major feature of the Kyoto Protocol is that it sets binding targets for 37 industrialized countries and the European community for reducing greenhouse gas (GHG) emissions.

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L

Term/Acronym Entity/Meaning Definition/Context
LUC Land Use Change A change in the use or management of land by humans. The Intergovernmental Panel on Climate Change (IPCC) distinguishes six broad land use categories: forestland, cropland, grassland, wetlands, settlements, and other land (e.g. bare soil, rock and ice), where the conversion from one land use category to another is called LUC.
LCA Life Cycle Analysis Life cycle analyses (LCA) is a methodology that evaluates the entire spectrum of impact of a product over its whole life cycle. In the case of biofuels, LCA generally refers to a calculation of CO2 or GHG emissions from initiation of feedstock production to combustion of the fuel in a vehicle.
LLC Limited Liability Company Limited Liability Company (LLC) is a business structure allowed by state statute. LLCs are popular because, similar to a corporation, owners have limited personal liability for the debts and actions of the LLC. Other features of LLCs are more like a partnership, providing management flexibility and the benefit of pass-through taxation. Owners of an LLC are called members. Since most states do not restrict ownership, members may include individuals, corporations, other LLCs, and foreign entities. There is no maximum number of members. Most states also permit “single member” LLCs, those having only one owner. A few types of businesses generally cannot be LLCs, such as banks and insurance companies. Check your state's requirements and the federal tax regulations for further information. There are special rules for foreign LLCs.
LTO Landing and Take-Off emissions All aircraft activities that take place at altitudes under 914 meters (3.000 feet), including taxi-in and -out, take-off, climb-out, and approach-landing

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M

Term/Acronym Entity/Meaning Definition/Context
MJ Mega Joule One million joules, symbolized by MJ
Megaton (i.e., of CO2) 1 Million Tons A unit typically used for the measurement of the mass of CO2 emitted by a process or entity. The unit is typically expressed in metric tonnes.
Metric Ton (or tonnes)   1,000 Kilograms or 2,205 Pounds
MOU or MoU Memorandum of Understanding A document describing a bilateral or multilateral agreement between parties. It expresses a convergence of will between the parties, indicating an intended common line of action. It is often used in cases where parties either do not imply a legal commitment or in situations where the parties cannot create a legally enforceable agreement. It is a more formal alternative to a gentlemen's agreement. In some cases, depending on the exact wording, MoUs can have the binding power of a contract; as a matter of law, contracts do not need to be labeled as such to be legally binding. Whether or not a document constitutes a binding contract depends only on the presence or absence of well-defined legal elements in the text proper of the document (the so-called “four corners”). For example, a binding contract typically must contain mutual consideration—a legally enforceable obligations of the parties, and its formation must take place free of the so-called real defenses to contract formation (fraud, duress, lack of age or mental capacity, etc.).

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N

Term/Acronym Entity/Meaning Definition/Context
N2O (N2O, N2O) Nitrous Oxide Chemical emitted from natural biosphere activity, certain agricultural (natural and human influenced), and industrial activities, as well as during combustion of fossil fuels (primarily in internal combustion engines, and not turbine engines). N2O is a potent greenhouse gas and Stratospheric Ozone depletion agent. It is used as an oxidizer in rocket motors, and as an anesthetic and analgesic. See also NOx.
NASA National Aeronautics Space Administration The National Aeronautics Space Administration's (NASA) mission is to pioneer the future in space exploration, scientific discovery, and aeronautics research.
NATA National Air Transportation Association The National Air Transportation Association (NATA) is the leading organization representing aviation service businesses such as fixed base operators, charter providers, aircraft management companies including those supporting fractional shareholders, maintenance and repair organizations, flight training, and airline service companies. Founded in 1940, NATA aggressively promotes safety and the success of aviation service businesses through its advocacy efforts before government, the media, and the public as well as by providing valuable programs and forums to further its members' prosperity.
NERD Non-Esterified Renewable Diesel Technical moniker associated with Renewable Diesel which is produced through hydrotreating, similar to HEFA-SPK. This nomenclature differentiates this type of diesel from the product commonly described as biodiesel (produced via esterification, FAME).
NOX, NOx, NO, NO2 (NO2, NO2) Oxides of Nitrogen, or Nitrogen Oxides Nitrogen oxides produced by the reaction of naturally occurring nitrogen and oxygen gases in the air during combustion. NOx gases react to form smog, acid rain, and ozone. The production of NOx from gas turbine engines for aviation is regulated.

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O

Term/Acronym Entity/Meaning Definition/Context
O2 Oxygen  
O3 Ozone  
OEM Original Equipment Manufacturer An original equipment manufacturer, or OEM, manufactures products or components which are purchased by a purchasing company and retailed under the purchasing company's brand name. OEM refers to the company that originally manufactured the product.
Offtake Agreement   An agreement between a producer of a resource and a buyer of a resource to purchase/sell portions of the producer's future production.
Olefins   Any of a class of unsaturated open-chain hydrocarbons such as ethylene, having the general formula CnH2n
Oligomerization   A chemical process that converts monomers to a finite degree of polymerization; can be used to convert alcohols such as ethanol (a C2 molecule) into longer chain hydrocarbons such as jet fuel (C8, C10, C12, C14, C16). See also ATJ (Alcohol-to-Jet).

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P

Term/Acronym Entity/Meaning Definition/Context
Petroleum   A generic term applied to oil and oil products in all forms, such as crude oil, lease condensate, unfinished oils, petroleum products, natural gas plant liquids, and non-hydrocarbon compounds blended into finished petroleum products
Pipeline   A pipe used to transport liquids or gases
PM Particulate Matter Tiny particles of volatile and nonvolatile solid or liquid suspended in a gas or liquid
Pyrolysis   Pyrolysis is the chemical decomposition of condensed organic substances by heating in a low oxygen environment (to prevent combustion). Can be used to convert plant material to crude oil that can be used for biofuels.

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Q

Term/Acronym Entity/Meaning Definition/Context
Qualification (of fuel)   Qualification processes are used by specification-writing organizations such as ASTM International to develop new fuel specifications, or to revise existing specifications (e.g. to add a new alternative fuel). These qualification processes will include a technical evaluation of the fuel followed by development of the specification requirements and criteria.

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R

Term/Acronym Entity/Meaning Definition/Context
REACH Renewable Acid-hydrolysis Condensation Hydrotreating Process of converting lignocellulosic biomass to a biocrude via acid hydrolysis, followed by a condensation step to create carbon chains which are then hydrotreated to convert the bio-crude into drop-in fuel
Refinery   A production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value
Refining   The process of purification of a substance or a form; e.g., crude oil into refined petroleum products
Renewable Energy   Energy generated from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished)
RJF Renewable Jet Fuel See also Biofuel.

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S

Term/Acronym Entity/Meaning Definition/Context
S Sulfur The element sulfur, often found in petrochemical feedstocks. When combusted, any sulfur present in the fuel oxidizes to form oxides of sulfur (often referred to as SOx), which are a major air pollutant (contributing to acid rain and atmospheric particulates). This factor is the driving force behind efforts to introduce ultra-low sulfur fuels. Sulfur does have the positive effect of being a natural lubricant in jet engine fuel system components, so its complete removal will drive the need for incorporating lubricity additives for the fuel.
SAF Sustainable Aviation Fuel or Sustainable Alternative Fuel Terminology preferred by international and EU stakeholders to describe conventional jet fuel blended with jet fuel derived from sustainable alternatives to petroleum.
SAF Sustainable Aviation Fuel Aviation fuels produced sustainably from renewable resources (in whole or in part). See also Biofuel. This was CAAFI’s preferred terminology before agreeing to use the term SAF as preferred by international stakeholders in support of industry solidarity.
SIP-SPK Synthetic Paraffinic Kerosene created from Synthesized Iso-Paraffins Nomenclature for an approved process for the creation of jet fuel blending component using synthesized iso-paraffins from the specialized fermentation of sugars. The specification for this fuel is included in ASTM D7566, Annex A3.
SK Synthetic Kerosene A very generic term for jet fuel produced from a non-petroleum sources. See also Alternative Fuels.
SKA Synthetic Kerosene with Aromatics A more descriptive but still generic term for a jet fuel blending component that contains aromatic content
SO2, (SO2, SO2) or SOx Sulfur dioxide, or Oxides of Sulfur generically See definition of Sulfur.
SOAP-Jet Seminars on Alternatives to Petroleum-Jet CAAFI's R&D Team webinar series focused on the co-processing of biofuels within existing refinery systems with an emphasis on the applicability of this approach to produce aviation biofuels.
SPK Synthetic Paraffinic Kerosenes Drop-in alternative jet fuel blending component consisting of paraffins derived from non-petroleum sources (often biofuels). It is not a complete replacement for jet fuel as is does not contain cyclo-paraffins or aromatics. See Jet Fuel.
STG+   STG+ gas-to-liquids technology is a thermochemical catalytic process to convert syngas derived from natural gas, biomass, or municipal solid waste into methanol, which is dehydrated into dimethyl ether and then converted via catalysis, transalkylation ,and hydrogenation into drop-in transportation fuels, such as gasoline, jet fuel, and aromatic chemicals.
Stranded assets   An asset that is worth less on the market than it is on a balance sheet due to the fact that it has become obsolete in advance of complete depreciation
Supplier   Entity that provides goods or services to a company
Supply Chain   A system of organizations, people, technology, activities, information, and resources involved in moving a product or service from supplier to customer
Sustainable Energy   The provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs
SWAFEA Sustainable Way for Alternative Fuel and Energy in Aviation European Commission effort that funded an alternative-fuel-for-aviation initiative
Syngas Synthesis Gas Syngas is the abbreviation for Synthesis gas. This is a gas mixture that is comprised of carbon monoxide, carbon dioxide, and hydrogen. The syngas is produced due to the gasification of a carbon-containing fuel to a gaseous product that has some heating value.
Synthetic Biology   Synthetic biology refers to both the design and fabrication of biological components and systems that do not already exist in the natural world and the re-design and fabrication of existing biological systems. Currently being used by some biofuels companies to convert raw materials into hydrocarbons using biological processes.
Synthetic Fuel   Liquid fuel obtained from non-petroleum feedstocks (coal, natural gas, or biomass)
Synthetic Jet Fuel   A jet fuel derived from non-petroleum sources, as defined by ASTM 7566

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T

Term/Acronym Entity/Meaning Definition/Context
TAG, TG, triglyceride Triacylglycerol, triacylglyceride, or triglyceride The primary constituent of naturally occurring plant and animal oils composed of three fatty acid molecules attached to a single glycerol molecule
Tallow   See Animal Oils.
Tank Farm   A facility for storage of liquid petroleum products or petrochemicals
Throughput   The rate at which something can be processed, often mass or volume per day or year
TRB Transportation Research Board TRB is one of six major divisions of the National Research Council—a private, nonprofit institution that is the principal operating agency of the National Academies in providing services to the government, the public, and the scientific and engineering communities. The National Research Council is jointly administered by the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The Transportation Research Board engages professionals worldwide in a broad range of interdisciplinary, multimodal activities for innovative transportation solutions.

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U

Term/Acronym Entity/Meaning Definition/Context
UCO (UVO, RVO, WVO, tallow) Used cooking oil (UCO), used vegetable oil (UVO), recycled vegetable oil (RVO), waste vegetable oil (WVO), or yellow grease Oil (typically plant oils, but not always) from cooking processes (homes, restaurants, industrial applications) that is discarded/recycled after reaching its useful life. It has subsequent use for animal feed and the manufacture of soap, make-up, clothes, rubber, and detergents. It is being used as a feedstock for biofuel production. Differs from Brown Grease which is typically recovered from grease traps in sewage treatment facilities, and often contains significant contaminants that make its re-use difficult.
UHCs Unburned hydrocarbons Hydrocarbons that are not completely converted to CO2 during the combustion process due to some inefficiency, subsequently considered to be contaminates or particulates in the engine exhaust
ULS(D) Ultra Low Sulfur (e.g., Ultra low sulfur diesel) For diesel, defined as having a maximum 15 parts per million (ppm) sulfur content
Uplift/Uptake The use of fuel onboard an aircraft Refers to the concept of loading the fuel onto an aircraft for usage on the next flight. Can be specific in its meaning of how much fuel is loaded onto the aircraft (mass or volume).
USAF, AF United States Air Force The United States Air Force (USAF) is the aerial warfare service branch of the United States Armed Forces.
USDA United States Department of Agriculture The U.S. Department of Agriculture is the federal department charged with coordinating and supervising all agencies and functions of the government relating directly to agriculture—providing leadership on food, agriculture, natural resources, rural development, nutrition, and related issues based on sound public policy, the best available science, and efficient management.

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W

Term/Acronym Entity/Meaning Definition/Context
WTI West Texas Intermediate Also known as Texas Light Sweet, WTI is a type of crude oil used as a benchmark in oil pricing and the underlying commodity of New York Mercantile Exchange's oil futures contracts.

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Y

Term/Acronym Entity/Meaning Definition/Context
Yellow Grease   Yellow Grease is the product produced from the recycling of used cooking oil. It is being used as a feedstock for biodiesel production.

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