“High fuel prices, coupled with tremendous volatility, have made identifying new fuels a priority for the aviation industry.”
Suzanne Hunt, Senior Advisor, Carbon War Room

Industry Background

Air travel currently transports two billion people a year and 43 million tons of goods – but emits 650 million tons of CO2 in the process. Though ships and cars produce more total pollution than airplanes, we are increasingly flying for holidays, city breaks and business. The Intergovernmental Panel on Climate Change (IPCC) reports that aviation is responsible for approximately 2%, of annual anthropogenic CO2 emissions. Unchecked, the aviation sector could be responsible for over 5% of global emissions by 2050.

The aviation industry has made great strides in improving its efficiency. Better plane and engine design, towing to and from gates and more gradual descents on landing are all making a significant difference. Yet despite these improvements emissions from aviation are still growing, therefore government regulation is also growing in some regions. In Europe for example, the European Commission is putting a price on carbon, asking airlines to either reduce their emissions or purchase CO2 permits for every ton they emit above their allowances. Advanced satellite navigation systems could be phased in to help aircraft to choose the more fuel-efficient flight path every time, but this transition is expected to span a decade or more.

Price Of Fuel

The aviation industry is highly vulnerable to fuel price fluctuations, with fuel representing 33% of an airline’s operating costs on average. Airlines spent $140 billion on jet fuel in 2010. That cost is expected to reach $200 billion in 2012. High prices, coupled with tremendous volatility, have made identifying new fuels a priority for the industry.

As a result, the renewable jet fuel industry has grown rapidly over the past five years:

  • Dozens of companies are developing viable renewable jet fuels
  • More than ten demonstration-scale operations have been brought online worldwide
  • The US military is engaged in testing, certifying and purchasing renewable fuels; they along with USDA and DOE are committed to spending $510 million on co-financing production facilities
  • ASTM, a globally recognised leader in the development and delivery of international voluntary consensus standards, is designing and approving systematic specifications for renewable aviation fuels (with two complete and several more in the pipeline).
  • 23 major airlines, comprising The Sustainable Aviation Fuel Users Group, have pledged to use renewable fuels with lower carbon impact
  • More than ten commercial airlines have carried flights using renewable jet fuel since HRJ/HEFA was approved for use in July of 2011.
Opportunities

Early stage companies in the renewable jet fuel industry are struggling to meet capital requirements, due in part to investor uncertainty in this landscape of complex technologies and markets. These concerns surround the entire value chain and include scale-up risk, technology status, environmental and carbon impact, and feedstock availability, as well as perhaps the most important factor – costs.

New low-carbon biofuels could help to provide the aviation sector with enhanced energy and price security while significantly reducing its CO2 emissions. However, to overcome the powerful backlash to the first generation of biofuels, strong, credible sustainability standards have to be created – only then will this new generation of fuels earn public acceptance. Additionally, they must be practical, workable and affordable for businesses to adopt them. Finally, for these standards to facilitate industry growth and not become a barrier to international trade, they must be truly international in nature.

The Carbon War Room believes that increased transparency and access to information will accelerate the formation of the renewable jet fuel market (as well as additional related renewable markets).

What is Renewable Jet Fuel?

Unlike fossil fuels, which are extracted from the ground, burned, and cannot be replenished, renewable fuels can be made over and over again. These fuels can be made from things like natural waste – wood waste, sugar, vegetable oil, grasses – or even your garbage. Or they can be made from more imaginative sources, like pollution from factories and algae.

What makes for a good or bad source of renewable fuel? What makes them sustainable or not? Renewable fuels shouldn’t compete for food or replace natural forests or other natural habitats. They should produce less total pollution than the conventional fossil fuels that they displace. And their benefits and safety should be scientifically tested and proven.

Read more about the different types of renewable jet fuels and what they are made from...

Renewable jet fuels are nearly chemically identical to conventional fossil jet fuels, only they are produced from renewable resources.

Unlike biodiesel or ethanol, advanced biofuel processing technologies produce fuels that are completely fungible with conventional petroleum-based fuels. These fuels generally meet or exceed the performance criteria of the petroleum fuels they replace. Renewable jet fuels under development, the conversion technologies that produce them and the resources from which they are made are described below.


HEFA (or HRJ), Produced from Hydroprocessing Natural Oils HEFA (hydroprocessed esters and fatty acids), sometimes also called HRJ (hydroprocessed renewable jet), are produced by 'refining' natural oils, much as petroleum is refined today. Hydroprocessing natural oils (plant oils or animal fats) involves converting these oils from lipids to hydrocarbons through the addition of hydrogen. The first step converts the lipids to fully saturated hydrocarbons, or synthetic paraffins, by saturating oxygen bonds and double-carbon bonds with hydrogen. These hydrocarbons are then selectively cracked and isomerised to produce primarily diesel, jet fuel and propane. This process can be integrated into existing fossil fuel refining facilities and operated at similar costs to petroleum refining. They can also be added on to first-generation biodiesel production facilities, or built from scratch in stand-alone refineries.

**Note that HEFA fuels are ASTM certified for commercial use in up to a 50/50 blend with conventional jet fuel.

FT-SPK, produced from biomass gasification and Fischer-Tröpsch Synthesis FT-SPK (Fischer-Tröpsch Synthetic Paraffinic Kerosene) is made by gasifying (you can think of gasifying as vaporising) biomass using heat and controlled amounts of oxygen and steam and then using the FT process to turn the vapors (called synthetic gas, or ‘syngas’, consisting of carbon monoxide and hydrogen) into liquid fuels. The syngas is converted into a synthetic paraffinic wax via the FT catalytic process. As in hydroprocessing, this paraffinic wax is then selectively cracked and isomerised to produce liquid fuels that are compatible with existing infrastructure. Note that this process can also be used to turn coal and natural gas into "non-renewable fuels", generally referred to as CTL (coal to liquid) and GTL (gas to liquid) fuels.

**Note that FT-SPK fuels are ASTM certified for commercial use in up to a 50/50 blend with conventional jet fuel.

ATJ (Alcohol to Jet) ATJ (Alcohol to Jet) is made via alcohol oligomerisation which involves linking short-chain alcohol molecules (e.g. ethanol or butanol) together to form jet-fuel range hydrocarbons. There are several chemistries that can be employed to oligomerise alcohols. In each of these processes, water and/or oxygen are removed from the alcohol molecules, and hydrogen is added. The starting alcohol volume is reduced during the conversion to hydrocarbon jet fuel (eg it takes approximately two gallons of ethanol to make one gallon of renewable jet fuel).

PTJ (Pyrolysis to Jet), produced from biomass pyrolysis. Pyrolysis refers to the thermal decomposition of biomass into pyrolysis oil. Biomass is heated under extreme temperatures in the absence of any reactive gaseous compounds. The biomass is converted into low-quality oil that must then be upgraded for processing into fuels. Hydroprocessing, described above, is the principal method by which pyrolysis oil is converted to fuels. Gasoline, aromatics and chemicals are the principal products of this production method, although jet fuel can be co-produced.

FRJ (Fermented Renewable Jet), or Fermentation-Based Biomass-to-Liquid Synthesis. In this approach, sugars are fermented by microorganisms that directly metabolise them into hydrocarbon fuels that can be used as jet fuel with little or no additional chemical processing. A number of companies are pursuing different microorganisms for this function, including heterotrophic algae, yeast, and bacteria.

Why aren't airlines already running on renewable jet fuel?

The renewable jet fuel industry is very young. Approval of the first two renewable jet fuels was only just achieved in 2009 and 2011 respectively. The early stage companies in the renewable jet fuel industry are struggling to meet capital requirements due in part to investor uncertainty in this complex technology and market landscape. These concerns surround the entire value chain, and include scale-up risk, technology status, environmental and carbon impact, feedstock availability, as well as perhaps the most important - costs. There is currently no publicly available source for measuring or comparing these factors across companies.

The Carbon War Room believes that increased transparency and access to information will accelerate the formation of the renewable jet fuel market (as well as additional renewable markets since most companies who produce renewable jet fuel also produce other renewable fuels and chemicals). Participants in the industry need a more complete understanding of the firms in the supply chain, risks, technology performance and differentiation, and scalability.

What is renewable jet fuel made from?

The renewable jet fuels described on the fuels page are generally produced from lingo-cellulosic biomass (e.g. forestry and agricultural residues), natural oils (eg plant oils and animal fats), and sugars (eg from sugar cane, sugar beet or sweet sorghum). These broad feedstock categories are described below.

In addition to renewable fuels produced from converted biomass, natural oils, or sugar feedstocks, there are early-stage technologies under development that seek to directly synthesize renewable fuels from CO or CO2 via chemical, metal and biological catalysts.

Biomass
Biomass includes any plant material containing sugar, starch, cellulose or other complex carbohydrates as target compounds for conversion into fuels. These feedstocks include municipal, agricultural and forestry wastes. Dedicated biomass energy crops are also used, including sugar cane, switchgrass, sorghum, miscanthus, willow, poplar or macroalgae.
Natural Oils
Natural Oils feedstocks are triglycerides or fatty acids and can be extracted (or secreted from) plants and microorganisms. Oilseed plants, including Camelina, Jatropha, Castor, Oil Palm and other crops, can produce oil-bearing seeds. Aquatic microorganisms, such as algae and cyanobacteria, can accumulate and sometimes secrete natural oils. Yields vary dramatically, as do the amount and types of land used for these crops. The scale potential and environmental impacts of natural oils feedstocks will accordingly be highly variable and site specific.
Sugars
Some plant sugars are readily extractable/digestible, such as parts of cane sugars. Sugars can also be derived from biomass via a chemical or enzymatic hydrolysis process, unlocking water-soluble C5 and C6 sugars. The scale potential for biofuels derived from cellulosic sugars is massive, but these technologies are not yet fully commercialised – though several companies may be close. There are also early stage companies developing photosynthetic microbes that can fix CO2, synthesise, and then secrete sugars for collection, thus decoupling sugar production from agricultural land use.
CO, CO2
Several biofuel conversion processes utilise waste CO or CO2 from other industrial processes as their primary input. These gases can be converted directly to fuels via fermentation, photosynthesis or chemical catalysis.
Key Acronyms & Terms
AAAE
American Association of Airport Executives is the trade association representing airport executives and airport management personnel at airports in the US (www.aaae.org).
ACI
Airports Council International is an association representing the interests of airport operators and partners worldwide (www.aci.aero).
AEA
The Association of European Airlines (AEA) is a European trade association whose membership is comprised of 33 major European airlines (www.aea.be).
AIA
The Aerospace Industries Association represents manufacturers, aircraft suppliers, helicopters, unmanned aircraft systems, space systems, aircraft engines, missiles, material and related components, equipment, services and information technology in the US (www.aia-aerospace.org).
AIAC
The Aerospace Industries Association of Canada (AIAC) is a trade association promoting and facilitating Canadian competitiveness in the global aerospace industry (www.aiac.ca).
AIREG
The Aviation Initiative for Renewable Energy in Germany (AIREG) is a German trade association whose membership – comprised of German airlines, academic organizations, and other vested supply chain representatives – strives to support the development and introduction of renewable aviation fuels in Germany (www.aireg.de).
ATAG
The Air Transport Action Group (ATAG) is an international trade association representing the global air transport supply chain (www.atag.org).
ASTM
ASTM International, formerly known as the American Society for Testing and Materials (ASTM), develops international voluntary consensus standards. ASTM’s diverse members deliver the test methods, specifications, guides and practices that support industries and governments worldwide. (www.astm.org)
A4A
Airlines for America (A4A) is an industry association that works with business and regulatory organisations to promote secure air transportation in the US. Its name changed from Air Transport Association (ATA) to A4A in late 2011 (www.airlines.org).
ATC
Air Traffic Control (ATC) is a service provided by ground-based controllers who direct aircraft through controlled airspace and on the ground. ATC services all over the world separate aircraft to prevent collisions, organize and expedite the flow of traffic and provide information and other support for pilots.
ATJ
Alcohol to Jet fuel – ATJ (Alcohol to Jet) – is made via alcohol oligomerisation, which involves linking short-chain alcohol molecules (e.g. ethanol or butanol) together to form jet-fuel range hydrocarbons. There are several chemistries that can be employed to oligomersze alcohols. In each of these processes, water and/or oxygen are removed from the alcohol molecules, and hydrogen is added. Note that the starting alcohol volume is reduced during the conversion to hydrocarbon jet fuel (e.g. it takes approximately two gallons of ethanol to make one gallon of renewable jet fuel).
ATM
Air Traffic Management (ATM) encompasses the processes, procedures and resources that monitor controlled air space and direct aircraft both on the ground and in the air. ATM is comprised of the following complementary systems: Airspace Management, Air Traffic Flow and Capacity Management (ATFCM), and Air Traffic Control (ATC).
Biofuels
Liquid fuels derived from organic matter or "biomass".
Bio SPK
Synthetic Paraffinic kerosene from vegetable oils or animal fats, also called hydroprocessed renewable jet (HRJ).
BTL
Biomass-To-Liquids (BTL) is a process used to produce liquid biofuels from solid biomass.
CAAFI
The Commercial Aviation Alternative Fuel Initiative (CAAFI) is a coalition, with funding for the one full-time director from the United States FAA, working with commercial airlines to advance the emerging alternative fuels industry. CAAFI is most notable for its work accelerating the testing and technical certification of new types of renewable jet fuels (www.caafi.org).
Carbon
In the context of climate change, 'carbon' is often used interchangeably with carbon dioxide (CO2). CO2 (or CO2e where the 'e' stands for equivalent) is often used as a proxy for a range of green house gases.
CO2e
Greenhouse gas emissions in carbon dioxide equivalents. Generally includes the six greenhouse gas groups covered by the Kyoto Protocol: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6).
CNS
Communications, Navigation and Surveillance.
CSF
The Commercial Spaceflight Federation (CSF) is a US-based industry association for businesses and organizations working to make commercial human spaceflight a reality (www.commercialspaceflight.org).
Drop-in fuel
An alternative fuel that meets all the requirements of current fossil fuel specifications and does not require any modification to equipment or infrastructure.
Energy crops
Defined here as woody crops or grasses grown for energy uses.
EU ETS
The European Union Emissions Trading Scheme (EU ETS) is a significant element of the EU's policy-based effort to curb and reduce industrial greenhouse gas emissions (http://ec.europa.eu/clima/policies/ets/index_en.htm).
European Advanced Biofuels Flight path Initiative
The European Advanced Biofuels Flight path Initiative is a roadmap initiative launched in 2011 by the European Commission (EC) services, in coordination with Airbus and four major European airlines, to outline clear milestones to achieve annual production of two million tons of sustainable aviation biofuel by 2020 (http://ec.europa.eu/energy/renewables/biofuels/flight_path_en.htm).
FAA
The Federal Aviation Administration (FAA) is the agency of the United States government charged with providing a safe, efficient aerospace system for the US. (www.faa.gov/)
Feedstock
Feedstock refers to raw materials used in industrial processes. In the renewable fuel industry, feedstock refers to the materials that are being converted into liquid fuels for transportation.
FRJ
Fermented Renewable Jet (FRJ) or Fermentation-Based Biomass-to-Liquid Synthesis. In this approach, sugars are fermented by microorganisms that directly metabolise them into hydrocarbon fuels that can be used as jet fuel with little or no additional chemical processing. A number of companies are pursuing different microorganisms for this function, including heterotrophic algae, yeast, and bacteria.
FT
Fischer-Tröpsch (FT) synthesis, is the step in a liquid fuel production process – converting biomass, coal or methane to liquid fuels – when the synthesis gases are converted to liquid fuels.
F-T SPK
Fischer-Tröpsch Synthetic Paraffinic Kerosene (FT-SPK) is a type of jet fuel made by gasifying (you can think of gasifying as vaporising) biomass using heat and controlled amounts of oxygen and steam and then using the FT process to turn the vapors (called synthetic gas, or ‘syngas’, consisting of carbon monoxide and hydrogen) into liquid fuels. The syngas is converted into a synthetic paraffinic wax via the FT catalytic process. FT is named after German chemists Franz Fischer (1877–1948) and Hans Tropsch (1889–1935). The process is most often used to create FT diesel, a fuel for compression-ignition engines, but is also used to make FT kerosene for jets.
GBEP
The Global Bioenergy Partnership (GBEP) was created in 2005 by the Group of Eight (G8) – a forum for the governments of eight of the world's largest economies. GBEP brings together public, private, and government stakeholders to promote biofuel best practices, relevant capacity building, and sustainable development of bioenergy worldwide. Its secretariat is housed at the UN Food and Agriculture Headquarters in Rome (www.globalbioenergy.org).
GIACC
The Group on International Aviation and Climate Change (GIACC) formed within the International Civil Aviation Organization (ICAO) to address the inconsistency between the concept of “common but differentiated responsibilities” contained in the United Nations Framework Convention on Climate Change (UNFCC) and the concept of non-discrimination contained in the Chicago Convention as they relate to the aviation industry.
Gigaton
One gigaton is equal to one billion tons. In the context of this website, we are referring to one billion tons of carbon.
GHG Emissions
Greenhouse gas emissions (GHGs) include direct GHGs such as Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Perfluorocarbons (PFCs), Hydrofluorocarbons (HFCs), Sulphur hexafluoride (SF6) as well as for the indirect greenhouse gases such as SO2, NOx, CO and NMVOC. These gases trap heat from the sun within the earth’s atmosphere.
HEFA
Hydroprocessed esters and fatty acids (HEFA), sometimes also called HRJ (hydroprocessed renewable jet) are produced by “refining” natural oils (e.g. vegetable oils and animal fats) much like petroleum is refined today (see definition for HRJ).
HRJ
Hydroprocessed renewable jet fuel (HRJ), also referred to as HEFA, is a ‘drop-in’ aviation fuel produced by hydroprocessing a plant- or animal-based oil into a synthetic biobased fuel that is nearly chemically identical to conventional petroleum-based jet fuel.
HVO
Hydrotreated Vegetable Oil (HVO) is a road transport biofuel derived from vegetable oils.
IATA
International Air Transport Association (IATA) is a global trade association comprised of approximately 240 airline members, as well as manufacturers, air traffic controllers and airports. IATA supports industry-wide fuel efficiency targets of 1.5% improvement per year through 2020.
ICAO
International Civil Aviation Organization (ICAO) is a specialised agency of the United Nations, created in 1944 to promote the safe development of international civil aviation. The Kyoto Protocol calls for aviation emissions to be limited and reduced via ICAO (www.icao.int).
ILUC
Indirect Land Use Change (ILUC), as described in an IUCN report, refers to changes in land use that arise from the displacement of an existing land use practice as a result of a new land use practice coming into place. This can occur on a spectrum from local to global: local displacement of human uses of a given resource, e.g. land or shoreline. Increasing market demand for agricultural commodities must be met by increased supply in national, regional and/or global markets. Many different human activities have the potential to cause ILUC. ILUC is an important and controversial issue, in part because the conversion of natural lands (e.g. forests) results in massive GHG emissions, habitat destruction and potential biodiversity loss and other negative impacts. For those biofuels that use feedstocks that come from the land base (as opposed to waste feedstocks), concerns have arisen that ILUC will result from the expansion of agricultural lands for biofuel feedstock production.
ISEAL Alliance
The ISEAL Alliance is a global association that works with established and emerging sustainability standards and certification efforts and provides guidance and delivers programs designed to strengthen their social and environmental impacts. Their Codes of Good Practice are global references for developing standards and following them is seen by some certification professionals as essential to demonstrate credibility (www.isealalliance.org).
LCA
Life Cycle Analysis (LCA) is used to assess environmental impacts associated with a product's life from raw material extraction, to processing, manufacture, distribution, use, maintenance and disposal. LCAs can be done comprehensively for all environmental impacts of a given product, or for one or a few of them (e.g. water, GHGs etc). The green house gas emissions implications of renewable fuel production pathways are generally assessed on a full life-cycle basis.
Lignocellulosic
Biomass material containing lignin and cellulose e.g. wood, straw, grasses.
LUC
Land Use Change (LUC). Land cover generally refers to the physical, chemical or biological categorisation of a given land area. Land use generally refers to the human use of a given land area (e.g. cattle raising, recreation, urban development, etc.). LUC therefore generally refers to the changes in land cover or land use caused by humans. Some land use changes have dramatic GHG implications, such as the conversion of natural forests to agricultural land or urban development.
NextGen
The Next Generation Air Transportation System (NextGen) is being developed in the US to improve CNS (Communications, Navigation, and Surveillance) and ATM (Air Traffic Management). NextGen involves using satellite-based navigation and other advanced technologies, which will enhance the safety and efficiency of routes, approaches, etc. Europe is working on a sister effort called SESAR to modernise European air traffic control.
OEM
Original Equipment Manufacturer (OEM) refers to a company that originally produced a product or good. OEMs in the aviation industry include airplane and engine manufactures.
Oligomerisation
Oligomerisation is the chemical conversion of monomers to polymers.
PTJ (Pyrolysis to Jet), Produced from Biomass Pyrolysis
Pyrolysis refers to the thermal decomposition of biomass into pyrolysis oil. Biomass is heated under extreme temperatures in the absence of any reactive gaseous compounds. The biomass is converted into low-quality oil which must then be upgraded for processing into fuels. Hydroprocessing, described above, is the principal method by which pyrolysis oil is converted to fuels. Gasoline, aromatics and chemicals are the principal products of this production method, although jet fuel can be co-produced.
Renewable Fuels
Fuels made from renewable resources.
RSB
The Roundtable on Sustainable Biofuels (RSB) – the principal international multi-stakeholder initiative to define sustainable biofuels and develop a third-party certification scheme (http://rsbservices.org).
SAFUG
The Sustainable Aviation Fuel Users Group (SAFUG) is an alliance of 23 airlines that (with the participation of OEMs) represent approximately 15% of global jet fuel demand. The members pledged to procure only sustainable renewable jet fuels. SAFUG’s mission is to accelerate the development and commercialisation of sustainable aviation biofuels (www.safug.org).
Members:
  • AeroMexico
  • Air France
  • Air New Zealand
  • Alaska Airlines
  • ANA
  • Avianca
  • British Airways
  • Cargolux
  • Cathay Pacific
  • Etihad Airways
  • GOL
  • Gulf Air
  • JAL
  • KLM
  • Lufthansa
  • Qantas
  • SAS
  • Singapore Airlines
  • TAM
  • TUI Fly
  • Virgin America
  • Virgin Atlantic
  • Virgin Australia

Affiliates:

  • AirBus
  • Boeing
  • Embraer
  • UOP
  • Aeropuertos y Servicios Auxiliares
SESAR
Single European Sky ATM Research (SESAR) is being developed in Europe to improve Communications, Navigation, and Surveillance (CNS) and Air Traffic Management (ATM).
SH
Synthetic Hydrocarbons are hydrocarbons synthesised from unconventional feedstocks (e.g. biomass, coal, or natural gas).
SPK
Synthetic Paraffinic Kerosene includes fuels from Fischer-Tröpsch (FT) and hydroprocessed renewable jet (HRJ) processes.
SWAFEA

Sustainable Way for Alternative Fuels and Energy for Aviation is an agency under the European Commission's Directorate General for Transport and Energy focused on investigating the feasibility and the impact of the use of alternative fuels in aviation. The SWAFEA team involves 20 European and international organisations, representing all players in alternative aviation fuels – aircraft and engine manufacturing, air transport, oil industry, research and consulting organizations – covering a large spectrum of expertise in the fields of fuel, combustion and the environment, as well as agriculture (www.swafea.eu).
Synthetic Biology
Synthetic biology is a young area of biological research that combines science and engineering to design and construct new biological functions and systems not found in nature.
Synthetic Fuel
Synthetic fuel, also referred to as 'synfuel', is a term that refers to fuels produced via gasification of biomass, coal, or natural gas and Fischer-Tröpsch synthesis (which is most often used to create FT diesel, a fuel for compression-ignition engines, or a kerosene replacement/blend stock).
TTW
Tank-to-Wake (TTW) describes emissions from burning fuel in aircraft.
WTT
Well-to-Tank (WTT) describes emissions generated during the production and distribution of the fuel.
WTW
Well-to Wake (WTW) describes emissions from fuel production, distribution, and use in aircraft.
UNFCCC
United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty developed in 1992 aimed at stabilising atmospheric greenhouse gas concentrations (http://unfccc.int).