The DOI matches its Crossref record; 40 of the 41 references it cites were found in a registry or an index; none of the 120 sources its claims cite is checked for support yet.
Use of sustainable fuels in aviation: a review
Open accessAbstract
As the push for carbon-neutral transport continues, the aviation sector is facing increasing pressure to reduce its carbon footprint. Furthermore, commercial air traffic is expected to resume the continuous growth experienced until the pandemic, highlighting the need for reduced emissions. The use of alternative fuels plays a key role in achieving future emission goals, while also lowering the dependency on fossil fuels. The so-called sustainable aviation fuels (SAF), which encompass bio and synthetic fuels, are currently the most viable option, but hydrogen is also being considered as a long-term solution. The present paper reviews the production methods, logistical and technological barriers, and potential for future mass implementation of these alternative fuels. In general, biofuels currently present higher technological readiness levels than other alternatives. Sustainable mass production faces critical feedstock-related challenges that synthetic fuels, together with other solutions, can overcome. All conventional fuel replacements, though with different scopes, will be important in meeting long-term goals. Government support will play an important role in accelerating and facilitating the transition towards sustainable aviation.
Overview
AI snapshot
Written from the paper’s full text.
TL;DR
This review surveys sustainable aviation fuel pathways—bio-based drop-in SAF, synthetic power-to-liquid/e-fuels, hydrogen, and battery-electric propulsion—and assesses production, certification, barriers, and policy support. It concludes that drop-in SAFs are the most viable short- and medium-term option, with biofuels at higher readiness but feedstock-limited, while synthetic fuels and hydrogen/electric aircraft face cost or range barriers and are longer-term.
Key findings
- Aviation accounted for around 2.5% of global CO₂ emissions and 3.5% of global warming including non-CO₂ contributions; 2019 jet kerosene combustion reached 1027 MtCO₂. SAF use remains less than 0.1% of jet kerosene consumption, though SAF can reduce life-cycle carbon emissions up to 80%.
- ASTM has approved eight conversion pathways; certified blending ratios are 5–50% depending on the process, and D4054 certification takes 3–5 years and costs at least $5 million. HEFA-SPK has powered over 95% of all SAF flights to date.
- Biofuels currently have higher technology readiness than other alternatives, but sustainable mass production faces feedstock constraints; synthetic PtL/e-fuels avoid biomass feedstock issues but are currently too expensive. Hydrogen and battery aircraft are long-term options with range limits: large battery-powered aircraft are not expected to cover more than about 500 km by 2050, and liquid hydrogen contains 2.5 times more energy per kilogram than kerosene.
- Policy support is emphasized: ReFuelEU targets 2% SAF at EU airports in 2025 rising to 63% in 2050 for biofuels and 0.7% for e-fuels in 2030. Waste/residue lipids could account for at least 20 million tons of SAF and 20 million tons of renewable diesel, and 2030 global feedstock availability could provide around 135 million tons of SAF per year.
Methods
- Narrative review of alternative aviation fuels, covering drop-in SAF (bio and synthetic), hydrogen, and battery-electric propulsion, including production methods, certification, logistical/technological barriers, and future implementation.
- Draws on published literature, ASTM standards (D1655, D4054, D7566), ICAO/CORSIA, IATA, EU ReFuelEU, and third-party data/figures; no primary experimental data or systematic search protocol is reported.
- Main analysis is a qualitative synthesis and comparison of pathways, feedstocks, blending limits, costs, and policy targets.
Limitations
- The paper states that a complete, extensive description of possible biofuel feedstocks would fall outside its scope; it also notes that restrictions may apply to the availability of third-party data.
- No formal limitations section is provided; as a narrative review, it lacks a systematic search/selection method and reports no primary data.
- Evident from the text: cost, readiness, feedstock, and emissions figures rely on cited third-party sources and projections, which may change as technologies and policies evolve.
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Claims the paper makes
93 Not checked yet · 25 Own interpretation · 5 No basis given · 1 Own result
In the paper
“blending ratios for certified pathways only allow between 5 and 50% mixing, depending on the conversion process.”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [27] Chevron (2006). Alternative Jet Fuels, Chevron.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“commercial air traffic is expected to resume the continuous growth experienced until the pandemic”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
What the sources say
- Not checked yetcites [16] European Organisation for the Safety of Air Navigation (2022, January 10). EUROCONTROL Forecast Update 2021–2027. Available online: https://www.eurocontrol.int/publication/eurocontrol-forecast-update-2021-2027.
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, the latter are currently too expensive in comparison with the former”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Studies show that SAF can decrease life cycle carbon emissions up to 80% [29]”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [29] (2022, January 07). What is Sustainable Aviation Fuel (SAF)?. Available online: https://www.bp.com/en/global/air-bp/news-and-views/views/what-is-sustainable-aviation-fuel-saf-and-why-is-it-important.html.
plaindirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
““Drop-in” alternatives to conventional jet kerosene emerge as the best short-and medium-term choice”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“current usage still only accounts for less than 0.1% of jet kerosene consumption [2].”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [2] International Energy Agency (2022, January 05). Internatonal Energy Agency, Paris. Available online: https://www.iea.org/reports/aviation.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“It is important to notice that not all biofuels can be used in the aviation sector [40].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.1. Renewable Feedstocks
What the sources say
- Not checked yetcites [40] Air Transport Action Group (2017). Beginner’s Guide to Sustainable Aviation Fuel, Air Transport Action Group.
plain- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“That is not the case for biofuels made from first-generation feedstocks (edible crops), which is why these are not considered viable alternatives for future implementation [6,45].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.1. Renewable Feedstocks
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
- Not checked yetcites [45] Al-Salem, S.M. (2019). Bio-plastics and Biofuel: Is it the Way in Future Development for End Users. Plastics to Energy, William Andrew Publishing.
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In the paper
“this is not enough to remove the need for mitigation measures [2]”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [2] International Energy Agency (2022, January 05). Internatonal Energy Agency, Paris. Available online: https://www.iea.org/reports/aviation.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“recent long-term projections actually predict an 8% reduction in air passenger traffic for the year 2050 when compared with similar pre-pandemic studies [17]”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [17] Air Transport Action Group (2021). Waypoint 2050, Air Transport Action Group.
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In the paper
“the rate of improvement is progressively slowing down [21]”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [21] International Civil Aviation Organization (2022, January 07). Trends in Emissions that Affect Climate Change. Available online: https://www.icao.int/environmental-protection/Pages/ClimateChange_Trends.aspx.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“This is due to the use of nitrile O-rings, which require a minimum of 8% in the level of aromatic content in the fuel in order to function properly [27]”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [27] Chevron (2006). Alternative Jet Fuels, Chevron.
plaindirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“given the competitive nature of the market, this option appears to be unfeasible.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“the decline in air traffic is considered to be only temporary [16]”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [16] European Organisation for the Safety of Air Navigation (2022, January 10). EUROCONTROL Forecast Update 2021–2027. Available online: https://www.eurocontrol.int/publication/eurocontrol-forecast-update-2021-2027.
plain- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“SAF-suitable feedstocks can be grouped in four categories: oil, sugar, starch, and lignocellulosic feedstocks [41,46].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.1. Renewable Feedstocks
What the sources say
- Not checked yetcites [41] International Civil Aviation Organization (2017). Sustainable Aviation Fuels Guide, International Civil Aviation Organization.
- Not checked yetcites [46] PtX Hub (2022, January 13). How is Sustainable Aviation Fuel Produced?—Conversion Processes Explained. Available online: https://ptx-hub.org/how-is-saf-produced-conversion-processes-explained/.
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, these technologies are only viable as long-term solutions.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Biodiesel, for example, does not meet the performance requirements to enable its use in air-craft, mainly due to lower energy density and higher freezing point than Jet-A fuel [42].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.1. Renewable Feedstocks
What the sources say
- Not checked yetcites [42] Roberts, W.L. (2008, January 7). Bio jet fuels. Proceedings of the 5th International Biofuels Conference, New Delhi, India.
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“In December 2021, United Airlines performed a successful demonstration flight using 100% SAF in one of its engines [34].”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [34] (2022, January 13). United Flies World’s First Passenger Flight on 100% Sustainable Aviation Fuel Supplying One Of Its Engines. Available online: https://www.ge.com/news/reports/united-flies-worlds-first-passenger-flight-on-100-sustainable-aviation-fuel-supplying-one.
plainSingle case- Asserted: passes — The authors put it forward as true.
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In the paper
“Optimizing flight routes for minimum emissions rather than cost, improving maintenance schedules and other operational measures, as well as introducing further advancements in weight reduction materials and related technologies [2,20], bring important contributions to decrease emissions and should not be neglected, but are clearly insufficient.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [2] International Energy Agency (2022, January 05). Internatonal Energy Agency, Paris. Available online: https://www.iea.org/reports/aviation.
- Not checked yetcites [20] BBC Future Planet (2022, January 13). The Fastest Ways Aviation Could Cut Emissions. Available online: https://www.bbc.com/future/article/20210525-how-aviation-is-reducing-its-climate-emissions.
boosteddirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“power-to-liquids (PtL) options could present themselves as a better solution.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
hedged- Asserted: passes — The authors put it forward as true.
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In the paper
“There are two established pathways for production of PtL fuels-the Fischer-Tropsch (FT) pathway and the methanol pathway [63].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
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In the paper
“Aromatic compounds are also generated through this process, which is of extreme interest and could contribute towards achieving higher engine compatibility specifications, and to receive certification for higher blending ratios or, potentially, total replacement of conventional kerosene [63].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Jatropha (Jatropha curcas) is another potential lipid oil source as it can yield around 2.5-3 metric tons of oil per hectare [6].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Presently, the percentage of renewable content allowed in coprocessing is only up to 5%, and when this method was first approved it could only be obtained from lipids (plant oils and animal fats), but Fischer-Tropsch-derived biocrude (unrefined hydrocarbon content coming from an FT reactor) was also allowed in 2020 [71].”
§ Use of Sustainable Fuels in Aviation-A Review > Co-Processing
What the sources say
- Not checked yetcites [71] Commercial Aviation Alternative Fuels Initiative (2022, January 20). Two New Alternative Jet Fuel Production Pathways Approved. Available online: https://www.caafi.org/news/NewsItem.aspx?id=10502.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The main pro for using this plant as fuel feedstock is its ability to be grown on degraded soils, in otherwise non-arable lands such as in arid ecosystems [39].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Unlike biofuels, synthetic or e-fuels do not rely on biomass to produce liquid hydrocarbons.”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3. Synthetic Fuels
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The methanol pathway is an alternative that, while currently not yet certified by ASTM for jet fuel production [63,78], could present itself as an interesting option for the aviation sector.”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
- Not checked yetcites [78] International Civil Aviation Organization (2019). Power-to-Liquids (PTL): Sustainable Fuels for Aviation, International Civil Aviation Organization.
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In the paper
“These show significant potential both as oil and lignocellulosic feedstock.”
§ Use of Sustainable Fuels in Aviation-A Review > Halophytes
What the sources say
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The Fischer-Tropsch pathway requires syngas production, which will force that, if regular electrolysis is applied to obtain H 2 , an additional step of reducing the sourced CO 2 to CO must be undertaken [76].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [76] Neuling, 2020, Power-to-Liquid fuels for aviation—Processes, resources and supply potential under German conditions, Appl. Energy source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“With co-processing, biocrude is blended with crude-oil-derived middle distillates in a petroleum refinery [36].”
§ Use of Sustainable Fuels in Aviation-A Review > Co-Processing
What the sources say
- Not checked yetcites [36] Commercial Aviation Alternative Fuels Initiative (2022, January 15). Fuel Qualification. Available online: https://www.caafi.org/focus_areas/fuel_qualification.html.
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In the paper
“One advantage of this technology is that it is designed so that the hydrogen production requirements can be produced internally [74].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.3. Other Pathways
What the sources say
- Not checked yetcites [74] Ricardo Energy and Environment (2020). Targeted Aviation Advanced Biofuels Demonstration Competition—Feasibility Study. Report for Department for Transport, UK, Ricardo Energy and Environment.
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Despite being the only pathway that has passed to Phase 2 of D4054, this technology is still far from being ready for commercial scale production [67,74].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.3. Other Pathways
What the sources say
- Not checked yetcites [67] Directorate-General for Energy (2017). High Biofuel Blends in Aviation, European Commission.
- Not checked yetcites [74] Ricardo Energy and Environment (2020). Targeted Aviation Advanced Biofuels Demonstration Competition—Feasibility Study. Report for Department for Transport, UK, Ricardo Energy and Environment.
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“There are, however, known obstacles to future larger scale implementations, derived from the complexities involved with feedstock growth that may compromise long-term sustainability targets.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Waste gas from industrial processes in which decarbonization is an especially complex endeavor, such as the cement or limestone industries, could be used to create a CO 2 cascade-a process in which CO 2 from non-sustainable sources is re-utilized before being finally released into the atmosphere [76].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [76] Neuling, 2020, Power-to-Liquid fuels for aviation—Processes, resources and supply potential under German conditions, Appl. Energy source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Cerium oxide (ceria) is used as the redox-active material because this compound presents good properties regarding its high oxygen ion conductivity and cyclability [93].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.2. Sun-to-Liquid Process
What the sources say
- Not checked yetcites [93] (2022, January 09). SUN-to-LIQUID: Fuels from Concentrated Sunlight. Available online: https://www.sun-to-liquid.eu/.
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Nevertheless, using renewable energy is still fundamental for PtL fuels to show significant improvements in GHG emissions [76].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [76] Neuling, 2020, Power-to-Liquid fuels for aviation—Processes, resources and supply potential under German conditions, Appl. Energy source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Still, even by 2050, large battery-powered aircraft are not expected to cover distances of more than approximately 500 km [107].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.2. Battery Electric
What the sources say
- Not checked yetcites [107] International Air Transport Association (2019). Aircraft Technology Roadmap to 2050, International Air Transport Association.
hedged- Asserted: passes — The authors put it forward as true.
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In the paper
“As previously mentioned, drop-in fuels are the best short-and medium-term alternatives to address the climate issue, due to various technological and logistical factors [98].”
§ Use of Sustainable Fuels in Aviation-A Review > 3. Other Alternatives
What the sources say
- Not checked yetcites [98] Energy Monitor (2022, January 09). Aviation Emissions: “We can’t Wait for Hydrogen or Electric”. Available online: https://www.energymonitor.ai/sectors/transport/aviation-emissions-we-cant-wait-for-hydrogen-or-electric.
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In the paper
“These higher costs are due to significantly higher energy requirements for DAC when compared with point source capture [75].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [75] German Environment Agency (2016). Power-to-Liquids: Potentials and Perspectives for the Future Supply of Renewable Aviation Fuel, German Environment Agency.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Liquid hydrogen has a variety of properties that make it suitable to be a replacement for conventional kerosene, namely containing 2.5 times more energy per kilogram than kerosene [103].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [103] International Air Transport Association (2019). Fact Sheet 7: Liquid Hydrogen as A Potential Low-Carbon Fuel for Aviation, International Air Transport Association.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Furthermore, there are no NOx emissions with the usage of this propulsion system [104].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [104] Baroutaji, 2019, Comprehensive investigation on hydrogen and fuel cell technology in the aviation and aerospace sectors, Renew. Sustain. Energ. Rev. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Despite the excitement generated by the numerous environmental advantages that this technology can potentiate [97], it will not be ready for commercialization in the foreseeable future.”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.2. Sun-to-Liquid Process
What the sources say
- Not checked yetcites [97] SolarPACES (2022, January 09). “Sun-to-Liquids” Solar Fuels R&D Wins Recognition at Cop26. Available online: https://www.solarpaces.org/sun-to-liquids-solar-fuels-rd-wins-recognition-at-cop26/.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“If used as a liquid fuel replacement, and though the same combustion principles as with current aircraft apply, there would have to be engine reconfigurations to due to variations in the combustion gases and properties between the kerosene and hydrogen [104].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [104] Baroutaji, 2019, Comprehensive investigation on hydrogen and fuel cell technology in the aviation and aerospace sectors, Renew. Sustain. Energ. Rev. source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“This is mainly due to its small energy by volume number when compared with conventional kerosene, even in its liquid form [105].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [105] Airbus (2022, January 25). How to Store Liquid Hydrogen for Zero-Emission Flight. Available online: https://www.airbus.com/en/newsroom/news/2021-12-how-to-store-liquid-hydrogen-for-zero-emission-flight.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Aircraft propulsion through the use of batteries has the highest potential to reduce not only CO 2 emissions, but emissions of other GHGs, such as NOx as well [107].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.2. Battery Electric
What the sources say
- Not checked yetcites [107] International Air Transport Association (2019). Aircraft Technology Roadmap to 2050, International Air Transport Association.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, in the absence of revolutionary breakthroughs within this field, the scope of such alternatives will be limited mostly to short-range flights.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plainconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“while these focus primarily on safety”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“studies are being conducted on additives that enable emission reduction in GHG in various petroleum fuels [116]”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
What the sources say
- Not checked yetcites [116] Paneerselvam, P., Venkadesan, G., Panithasan, M.S., Alaganathan, G., Wierzbicki, S., and Mikulski, M. (2021). Evaluating the Influence of Cetane Improver Additives on the Outcomes of a Diesel Engine Characteristics Fueled with Peppermint Oil Diesel Blend. Energies, 14. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- It may state two separate claims as one. 57
- Probably not a substantial claim. 33
None of the sources cited for this claim have been checked yet.
In the paper
“The comprehensive and meticulous method set by D4054 requires different fuel volumes in each different tier, and the 3-5 year process has a cost of at least $5 million on candidate fuel producers [37,38].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.1. Certification Process Overview
What the sources say
- Not checked yetcites [37] Heyne, 2021, Sustainable aviation fuel prescreening tools and procedures, Fuel source
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“in January 2020, ASTM approved a Fast Track Annex to D4054, but new fuels approved under this process are limited to a 10% blend percentage [38].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.1. Certification Process Overview
What the sources say
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“other methods, such as using solar energy, are still in the early development phases.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
In the paper
“Biofuels from oil feedstocks used to be mostly produced from first-generation feedstocks, such as palm oil and soybean [41], but these can lead to sustainability issues”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [41] International Civil Aviation Organization (2017). Sustainable Aviation Fuels Guide, International Civil Aviation Organization.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“future progress is not expected to match the projected increase in air traffic, hence will therefore be insufficient”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [21] International Civil Aviation Organization (2022, January 07). Trends in Emissions that Affect Climate Change. Available online: https://www.icao.int/environmental-protection/Pages/ClimateChange_Trends.aspx.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“in order to accomplish the required results, it becomes necessary to lower and eventually end the dependency of commercial aviation on fossil fuels.”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence.
In the paper
“aviation is widely seen as the hardest sector to decarbonize, whether it is looked at from a technological or an economical standpoint [4].”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [4] Searle, S., Pavlenko, N., Kharina, A., and Giuntoli, J. (2019). Long-Term Aviation Fuel Decarbonization: Progress, Roadblocks, and Policy Opportunities, International Council on Clean Transportation.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“while also lowering emissions of other pollutants, such as soot [30], sulfur oxides, and ultrafine particles [31], as well as mitigating the climate impact of contrails [32].”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [30] Gaspar, 2016, Impact of alternative fuels on the operational and environmental performance of a small turbofan engine, Energ. Convers. Manag. source
- Not checked yetcites [31] Gladstein, Neandross & Associates (2020). Sustainable Aviation Fuel: Greenhouse Gas Reductions from Bay Area Commercial Aircraft, Gladstein, Neandross & Associates.
- Not checked yetcites [32] Narciso, M., and Sousa, J.M.M. (2021). Influence of Sustainable Aviation Fuels on the Formation of Contrails and Their Properties. Energies, 14. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Second-generation biofuels are comprised of non-food crops and other alternative raw materials that do not seek to compete with edible feedstocks for land usage, and are therefore more likely to meet the sustainability standards required.”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Sustainable mass production faces critical feedstock-related challenges that synthetic fuels, together with other solutions, can overcome.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
In the paper
“by 2019 more than a quarter of a million SAF flights had been performed by more than 45 commercial airlines [9]”
§ Use of Sustainable Fuels in Aviation-A Review > 2. Drop-In Alternatives
What the sources say
- Not checked yetcites [9] International Air Transport Association (2021). Fly Net Zero Information Pack, International Air Transport Association.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Government support will play an important role in accelerating and facilitating the transition towards sustainable aviation.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
In the paper
“the current generation of aircraft being 20% more efficient than the previous generation, and 85% more than those of the 1960s [2]”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
What the sources say
- Not checked yetcites [2] International Energy Agency (2022, January 05). Internatonal Energy Agency, Paris. Available online: https://www.iea.org/reports/aviation.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The so-called sustainable aviation fuels (SAF), which encompass bio and synthetic fuels, are currently the most viable option, but hydrogen is also being considered as a long-term solution.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“Since plants are the most common sources for biofuel production, associated carbon life cycle emissions can be significantly reduced, as some of the CO 2 will be reabsorbed by the next generation of crops [39].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2. Biofuels
What the sources say
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“All conventional fuel replacements, though with different scopes, will be important in meeting long-term goals.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The use of alternative fuels plays a key role in achieving future emission goals, while also lowering the dependency on fossil fuels.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Currently, biogenic feedstocks are most used, but sustainability poses as a major obstacle to larger-scale applications”
§ Use of Sustainable Fuels in Aviation-A Review > 1. Introduction
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Sometimes wastes from anthropogenic activities, especially industrial by-products, can also be considered as a separate feedstock category [47].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.1. Renewable Feedstocks
What the sources say
- Not checked yetcites [47] Commercial Aviation Alternative Fuels Initiative (2022, January 16). Feedstocks. Available online: https://www.caafi.org/focus_areas/feedstocks.html.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In general, biofuels currently present higher technological readiness levels than other alternatives.”
§ Use of Sustainable Fuels in Aviation-A Review > Abstract
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
In the paper
“One of the main advantages of producing SAF in petroleum refineries is the fact that the higher capacities of those refineries allows for higher fuel output, and offers significant cost reduction opportunities [72].”
§ Use of Sustainable Fuels in Aviation-A Review > Co-Processing
What the sources say
- Not checked yetcites [72] Tanzil, 2021, Production of Sustainable Aviation Fuels in Petroleum Refineries: Evaluation of New Bio-Refinery Concepts, Front. Energy Res. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The final annex to D7566, namely Annex A7, was approved in May 2020 and it covers for the production and use of a type of synthesized paraffinic kerosene from hydrocarbonhydroprocessed esters and fatty acids.”
§ Use of Sustainable Fuels in Aviation-A Review > Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK)
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“However, in 2018 co-processing of renewable content with conventional crude oil was approved and added to Annex A1 of ASTM D1655 [70].”
§ Use of Sustainable Fuels in Aviation-A Review > Co-Processing
What the sources say
- Not checked yetcites [70] Commercial Aviation Alternative Fuels Initiative (2022, January 20). Co-Processing Provision Approved and Added to ASTM 1655 Annex A1, Enables Renewable Feedstocks in Jet Fuel. Available online: https://www.caafi.org/news/NewsItem.aspx?id=10408.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Halophytes are a group of salt-tolerant grasses that can grow in areas where plant life normally could not prosper [39].”
§ Use of Sustainable Fuels in Aviation-A Review > Halophytes
What the sources say
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“The feedstocks suitable for jet fuel production through CH are similar to those of the HEFA pathway, with carinata being used during the qualification process [66][67][68].”
§ Use of Sustainable Fuels in Aviation-A Review > Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK)
What the sources say
- Not checked yetcites [66][67][68]
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“A use of only a small percentage of this type of soil could boost current SAF production numbers [6], without the need to compete with edible crops or being dependent on their rotation timelines [50].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
- Not checked yetcites [50] Hari, 2015, Aviation biofuel from renewable resources: Routes, opportunities and challenges, Renew. Sustain. Energ. Rev. source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“The difference lies in that, unlike the fatty acids or fatty acid esters found in HEFA production, this addition describes the hydroprocessing of bioderived hydrocarbons obtained from oils found in a specific algae (Botryococcus braunii), the only feedstock source for this conversion process [36,46,65,66,69].”
§ Use of Sustainable Fuels in Aviation-A Review > Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK)
What the sources say
- Not checked yetcites [36] Commercial Aviation Alternative Fuels Initiative (2022, January 15). Fuel Qualification. Available online: https://www.caafi.org/focus_areas/fuel_qualification.html.
- Not checked yetcites [46] PtX Hub (2022, January 13). How is Sustainable Aviation Fuel Produced?—Conversion Processes Explained. Available online: https://ptx-hub.org/how-is-saf-produced-conversion-processes-explained/.
- Not checked yetcites [65] SkyNRG (2022, January 20). Technology. Available online: https://skynrg.com/sustainable-aviation-fuel/technology/.
- Not checked yetcites [66] International Air Transport Association (2020). Fact Sheet 2: Sustainable Aviation Fuel: Technical Certification, International Air Transport Association.
- Not checked yetcites [69] Green Car Congress (2022, January 20). ASTM Approves 7th Annex to D7566 Sustainable Jet Fuel Specification: HC-HEFA. Available online: https://www.greencarcongress.com/2020/05/20200514-ihi.html.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“which in turn implies that, though research is not as advanced as is the case with bio SAFs, e-fuels could potentially become the best choice for short-and medium-term decarbonization efforts.”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3. Synthetic Fuels
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Solid oxide electrolysis (SOEL) is a recent, less developed technology when compared with AEL and PEMEL that is just now entering the market [83,85], but it is considered a more promising long-term option for carbon-neutrality pursuit [86].”
§ Use of Sustainable Fuels in Aviation-A Review > Electrolysis
What the sources say
- Not checked yetcites [83] Wulf, 2020, Review of Power-to-X Demonstration Projects in Europe, Front. Energy Res. source
- Not checked yetcites [85] Varone, 2015, Power to liquid and power to gas: An option for the German Energiewende, Renew. Sustain. Energ. Rev. source
- Not checked yetcites [86] Herz, 2021, Economic assessment of Power-to-Liquid processes—Influence of electrolysis technology and operating conditions, Appl. Energy source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“cover crops can also improve soil quality in comparison with monocropping [39], as it reduces erosion and improves water infiltration and carbon sequestration [6], though the sustainability benefits of this practice are still not completely clear and need further analysis”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
- Not checked yetcites [48] O’Malley, J., Pavlenko, N., Kharina, A., and Searle, S. (2021). Estimating Sustainable Aviation Fuel Feedstock Availability to Meet Growing European Union Demand, International Council on Clean Transportation.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Providing that the FT process employs iron or cobalt catalysts, ASTM does not restrict the feedstock origin for drop-in FT fuels, and so this pathway can already be used in commercial aircraft up to 50% blends [63,74].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
- Not checked yetcites [74] Ricardo Energy and Environment (2020). Targeted Aviation Advanced Biofuels Demonstration Competition—Feasibility Study. Report for Department for Transport, UK, Ricardo Energy and Environment.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Camelina can be used as a rotational cover crop [6].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Methanol is currently produced especially from syngas, through a sequence of exothermic reactions, and requires a stoichiometric H 2 /CO ratio of 2 for maximum efficiency [79].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [79] National Energy Technology Laboratory (2022, January 08). 10.3. Syngas Conversion to Methanol, Available online: https://netl.doe.gov/research/coal/energy-systems/gasification/gasifipedia/methanol.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Finally, Swedish Biofuels and Byogy are currently developing a variation of the ATJ process that can produce jet fuel with a higher level of aromatic content (ATJ-SKA) through the addition of an aromatization step, which is currently in Phase 1 Testing of D4054 [36,67].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.3. Other Pathways
What the sources say
- Not checked yetcites [36] Commercial Aviation Alternative Fuels Initiative (2022, January 15). Fuel Qualification. Available online: https://www.caafi.org/focus_areas/fuel_qualification.html.
- Not checked yetcites [67] Directorate-General for Energy (2017). High Biofuel Blends in Aviation, European Commission.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
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Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“This leads to a higher freezing point, which in turn means that less processing steps are required, giving it a production cost advantage over HEFA-SPK [74].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.2.3. Other Pathways
What the sources say
- Not checked yetcites [74] Ricardo Energy and Environment (2020). Targeted Aviation Advanced Biofuels Demonstration Competition—Feasibility Study. Report for Department for Transport, UK, Ricardo Energy and Environment.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Camelina (Camelina sativa) falls under this category.It is a non-edible energy crop with a high lipid oil content, its main use is precisely as a feedstock for fuel production and, after the oil extraction process, leftover material can also be used as feed supplement for livestock [39].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [39] Air Transport Action Group (2011). Beginner’s Guide to Aviation Biofuels, Air Transport Action Group.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“However, there is not a consensus regarding the sustainability and potential for GHG reduction in this process, with some companies arguing that fuel resultant from co-processing should be ineligible for SAF classification [73].”
§ Use of Sustainable Fuels in Aviation-A Review > Co-Processing
What the sources say
- Not checked yetcites [73] Environmental + Energy Leader (2022, January 20). Biofuel, Transportation Companies Ask Congress To Exclude Co-Processed Petroleum from Sustainable Aviation Fuel Credit. Available online: https://www.environmentalleader.com/2021/12/biofuel-transportation-companies-ask-congress-to-exclude-co-processed-petroleum-from-sustainable-aviation-fuel-credit/.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Although it is still far from being the most industrially used method to obtain H 2 [81], it is a growing market and the most promising process to achieve carbon-free hydrogen production [82].”
§ Use of Sustainable Fuels in Aviation-A Review > Electrolysis
What the sources say
- Not checked yetcites [81] International Energy Agency (2022, January 05). The Future of Hydrogen. International Energy Agency, Paris, Available online: https://www.iea.org/reports/the-future-of-hydrogen.
- Not checked yetcites [82] Office of Energy Efficiency and Renewable Energy (2022, January 09). Hydrogen Production: Electrolysis, Available online: https://www.energy.gov/eere/fuelcells/hydrogen-production-electrolysis.
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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It may state two separate claims as one.
In the paper
“Catalytic hydrothermolysis is one of the two pathways that were most recently certified for commercial use -again, with a maximum blending ratio of 50%-in 2020 (Annex A6 of D7566 in the case of CH).”
§ Use of Sustainable Fuels in Aviation-A Review > Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK)
What the sources say
- Not checked yetcites Annex A6 of D7566
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“These include low seed yield (and limited biogenetic studies on technologies that could help boost breeding programs, such as cloning and gene expression), susceptibility to viral infections and pests such as insects and rodents, and high complexity and cost of efficient oil extraction methods [51].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [51] Jacob-Lopes, E., and Zepka, L.Q. (2017). Jatropha Biofuel industry: The challenges. Frontiers in Bioenergy and Biofuels, IntechOpen. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“There have been, however, advancements in direct CO 2 to methanol conversion [80], which would eliminate the need for CO 2 reduction through RWGS, and thus improve cost efficiency of the whole production line.”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.1. Power-to-Liquids (PtL) Production Pathways
What the sources say
- Not checked yetcites [80] Bos, 2015, A novel condensation reactor for efficient CO2 to methanol conversion for storage of renewable electric energy, Chem. Eng. J. source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“It is also poisonous both to humans and animals so, unlike Camelina, leftovers from the oil extraction cannot be reused as fodder [49].”
§ Use of Sustainable Fuels in Aviation-A Review > Camelina
What the sources say
- Not checked yetcites [49] Farm Energy eXtension (2022, January 16). Jatropha: Biodiesel and More. Available online: https://farm-energy.extension.org/jatropha-biodiesel-and-more/.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“and though their potential flight coverage is limited, they can still play an important role in decarbonizing aviation, which is why numerous projects involving several airlines are currently under development [101].”
§ Use of Sustainable Fuels in Aviation-A Review > 3. Other Alternatives
What the sources say
- Not checked yetcites [101] Aviation Today (2022, January 09). 10 Airlines That Made Electric and Hydrogen-Powered Aircraft Investments, Partnerships in 2021. Available online: https://www.aviationtoday.com/2022/01/01/10-airlines-made-electric-hydrogen-powered-aircraft-investments-partnerships-2021/.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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It may state two separate claims as one.
In the paper
“Studies show that HHO has advantages over H 2 in reducing CO and CO 2 , and increased efficiency and reduction in some GHG emissions have been reported with duel-fuel setups in diesel engines [88].”
§ Use of Sustainable Fuels in Aviation-A Review > Electrolysis
What the sources say
- Not checked yetcites [88] Sekar, 2022, Optimisation of dry cell electrolyser and hydroxy gas production to utilise in a diesel engine operated with blends of orange peel oil in dual-fuel mode, Int. J. Hydrogen Energy source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“Unlike SAFs, which rely mostly on carbon offsetting to reduce life cycle emissions, the latter technologies would eliminate in-flight CO 2 emissions, and though their potential flight coverage is limited, they can still play an important role in decarbonizing aviation, which is why numerous projects involving several airlines are currently under development [101].”
§ Use of Sustainable Fuels in Aviation-A Review > 3. Other Alternatives
What the sources say
- Not checked yetcites [101] Aviation Today (2022, January 09). 10 Airlines That Made Electric and Hydrogen-Powered Aircraft Investments, Partnerships in 2021. Available online: https://www.aviationtoday.com/2022/01/01/10-airlines-made-electric-hydrogen-powered-aircraft-investments-partnerships-2021/.
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Another way to promote SAF use is through legislation, such as the European Commission's ReFuelEU Aviation, a mandate that sets specific targets for SAF integration in EU airports, from 2% in 2025 to 63% in 2050, for biofuels, and to 0.7% for 2030, for e-fuels [114].”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
What the sources say
- Not checked yetcites [114] GreenAir (2022, January 27). European Commission’s ReFuelEU Aviation Proposal Details SAF Blending Obligation on Fuel Suppliers. Available online: https://www.greenairnews.com/?p=1374.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Though demand is substantially lower when compared with biofuel production [75,78], sustainability issues may emerge if, for example, the used water source conflicts with agricultural land requirements, and such factors need to be evaluated before any future large-scale facilities enter production.”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [75] German Environment Agency (2016). Power-to-Liquids: Potentials and Perspectives for the Future Supply of Renewable Aviation Fuel, German Environment Agency.
- Not checked yetcites [78] International Civil Aviation Organization (2019). Power-to-Liquids (PTL): Sustainable Fuels for Aviation, International Civil Aviation Organization.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“There is some skepticism regarding the capability of biogenic feedstocks to address expected future fuel demand without compromising some of these obligations [63].”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, this process would still nevertheless increase CO 2 atmospheric levels, and so it is not a realistic option towards achieving future goals.”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Biofuels are closer to wide-scale commercialization than other alternatives, but, despite increasing number of flights using SAFs, especially employing HEFA-SPK, no pathway has yet achieved the highest technological readiness level [74]”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
What the sources say
- Not checked yetcites [74] Ricardo Energy and Environment (2020). Targeted Aviation Advanced Biofuels Demonstration Competition—Feasibility Study. Report for Department for Transport, UK, Ricardo Energy and Environment.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Water is necessary for hydrogen production (1.3-1.4 liters of water per liter of jet fuel [75]), as well as cooling and heating purposes during other phases [76].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [75] German Environment Agency (2016). Power-to-Liquids: Potentials and Perspectives for the Future Supply of Renewable Aviation Fuel, German Environment Agency.
- Not checked yetcites [76] Neuling, 2020, Power-to-Liquid fuels for aviation—Processes, resources and supply potential under German conditions, Appl. Energy source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“One of the main advantages of this technology is the high operational temperature range (up to 1000 • C [84]); this enables that waste heat to be reused from both the exothermic FT reaction or methanol synthesis [75], which reduces the energy demand and results in significantly higher efficiencies than AEL or PEMEL [87].”
§ Use of Sustainable Fuels in Aviation-A Review > Electrolysis
What the sources say
- Not checked yetcites [84] Gandía, L.M., Arzamendi, G., and Diéguez, P.M. (2013). Chapter 2–Water Electrolysis Technologies. Renewable Hydrogen Technologies, Elsevier. source
- Not checked yetcites [75] German Environment Agency (2016). Power-to-Liquids: Potentials and Perspectives for the Future Supply of Renewable Aviation Fuel, German Environment Agency.
- Not checked yetcites [87] Buttler, 2018, Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas and power-to-liquids: A review, Renew. Sustain. Energ. Rev. source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Power-to-liquid processes are also relying on new improvements in both high temperatures and co-electrolysis, and while at the moment they are nowhere near as close to compete with biofuels in terms of cost, it is expected that in the long-term this pathway becomes the most economically competitive [6].”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Hydrogen consumption has been progressively increasing in recent decades, but not on a sustainable manner, being mostly produced from gasification of coal or reforming of natural gas, with associated CO 2 emissions exceeding 800 million tons per year [81].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [81] International Energy Agency (2022, January 05). The Future of Hydrogen. International Energy Agency, Paris, Available online: https://www.iea.org/reports/the-future-of-hydrogen.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Drop-in fuels have the advantage on other alternatives, not only due to being more matured technologies, but also because their compatibility with current aircraft and logistics makes it possible to address the urgency of the problem.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Within this category, jet fuel from biogenic sources is currently easier and less expensive to produce in meaningful quantities, and can be achieved through several different pathways.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“In addi-tion, most fuel production pathways also generate other products, and even if production is optimized to obtain jet fuel, valorization of co-products should not be neglected [83].”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
What the sources say
- Not checked yetcites [83] Wulf, 2020, Review of Power-to-X Demonstration Projects in Europe, Front. Energy Res. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The combination of all these issues produce negative effects on the cost-effectiveness of SAFs, which, if these problems were to be left unaddressed, and the economic viability of these fuels remained questioned, could lead to a deceleration in the decarbonization efforts, thereby undoubtedly preventing the sector from achieving the set objectives for the next decades.”
§ Use of Sustainable Fuels in Aviation-A Review > 4. Challenges
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
In the paper
“H 2 fuel cell aircraft in development are only targeting short-range flights, and though hydrogen turbine aircraft are expected to be capable of flying larger distances, it is not expected that they will be able to cover long-distance flights [6].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.1. Hydrogen
What the sources say
- Not checked yetcites [6] World Economic Forum (2020). Clean Skies for Tomorrow: Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation, World Economic Forum.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Another possible feature form SOEL is the ability of co-electrolysis of CO 2 and steam to produce syngas, which would be of extreme interest since it would also eliminate the need for RWGS, but this technology is in an early development stage [63,87].”
§ Use of Sustainable Fuels in Aviation-A Review > Electrolysis
What the sources say
- Not checked yetcites [63] Schmidt, 2018, Power-to-Liquids as Renewable Fuel Option for Aviation: A Review, Chem. Ing. Tech. source
- Not checked yetcites [87] Buttler, 2018, Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas and power-to-liquids: A review, Renew. Sustain. Energ. Rev. source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Hybrid electric systems that combine electric and combustion engines can, therefore, provide a better alternative since these explore the advantages of both systems, and will also play an essential role in maturing electric aircraft technology [9].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.2. Battery Electric
What the sources say
- Not checked yetcites [9] International Air Transport Association (2021). Fly Net Zero Information Pack, International Air Transport Association.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“CO 2 from fossil origin is not a sustainable long-term solution but could be of interest in the short-term to prove production of scale [89].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [89] World Economic Forum (2020). Joint Policy Proposal to Accelerate the Deployment of Sustainable Aviation Fuels in Europe. A Clean Skies for Tomorrow Publication, World Economic Forum.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The two-step redox cycle guarantees that the syngas and O 2 are generated in separate steps, which avoids the formation of explosive mixtures while also removing the necessity for high-temperature gas separation [95].”
§ Use of Sustainable Fuels in Aviation-A Review > 2.3.2. Sun-to-Liquid Process
What the sources say
- Not checked yetcites [95] Rutz, 2022, Drop-in fuels from sunlight and air, Nature source
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“However, at the moment this is still an underdeveloped technology, and disputes regarding its feasibility for larger scale production due to high operating costs are ongoing [90].”
§ Use of Sustainable Fuels in Aviation-A Review > Resources
What the sources say
- Not checked yetcites [90] Keith, 2018, A Process for Capturing CO2 from the Atmosphere, Joule source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“E-Fan X, an Airbus partnership with Rolls-Royce and Siemens, was developed with the goal of building a hybrid electric demonstrator that could accommodate 50-100 passengers, but was canceled in 2020 before any flights were made [110].”
§ Use of Sustainable Fuels in Aviation-A Review > 3.2. Battery Electric
What the sources say
- Not checked yetcites [110] Airbus (2022, January 27). E-Fan X: A Giant Leap Towards Zero-Emission Flight. Available online: https://www.airbus.com/en/innovation/zero-emission/electric-flight/e-fan-x.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“gasoline ranges from molecules with 4-12 carbon atoms”
§ Use of Sustainable Fuels in Aviation-A Review > Additional information
What the sources say
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Synthetic fuels, especially from PtL methods, will likely become a protagonist in decarbonization, once current technological barriers are surpassed.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Similarly, hydrogen-and battery-powered aircraft can contribute, in the long term, to eliminate fossil dependency.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plainconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“Jet fuel, on the other hand, is a middle distillate of the two products-its molecules have 8-16 carbon atoms.”
§ Use of Sustainable Fuels in Aviation-A Review > Additional information
What the sources say
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“diesel can vary between 8 and 23 carbon atoms”
§ Use of Sustainable Fuels in Aviation-A Review > Additional information
What the sources say
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Among the additives used in jet fuel are anti-static chemicals, deicing agents, anticorrosive agents, and antibacterial agents [35,38,115]”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
What the sources say
- Not checked yetcites [35] Chevron (2007). Aviation Fuels: Technical Review, Chevron.
- Not checked yetcites [38] Office of Energy Eficiency and Renewable Energy (2022, January 13). Sustainable Aviation Fuels: Review of Technical Pathways, Available online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf.
- Not checked yetcites [115] Interesting Engineering (2022, January 27). What is the Difference between Jet Fuel and Gasoline?. Available online: https://interestingengineering.com/whats-the-difference-between-jet-fuel-and-gasoline.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“due to the particularities of air travel, specification regarding approval and use of additives is more complex, with some being mandatory while others are optional.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The particularities of air travel make the specification for approval and use of additives more complex.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“future technological breakthroughs are likely to be applied to SAF as well, which could help in boosting their environmental benefits.”
§ Use of Sustainable Fuels in Aviation-A Review > 5. Conclusions
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The main difference lies in the hydrocarbons that compose each type of fuel, most importantly the number of carbon atoms.”
§ Use of Sustainable Fuels in Aviation-A Review > Additional information
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Required emissions reductions are obtained through technology developments (T), operations and infrastructure improvements (O), use of sustainable aviation fuels (F), and offsets and other carbon mitigation options (M).”
§ Use of Sustainable Fuels in Aviation-A Review > Appendix A.2. Jet Fuel Properties
What the sources say
- Not checked yetcites [17] Air Transport Action Group (2021). Waypoint 2050, Air Transport Action Group.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Due to the different and more challenging operating conditions faced by air travel, jet fuel specifications must inherently differ from other types of fuels, such as gasoline and diesel.”
§ Use of Sustainable Fuels in Aviation-A Review > Additional information
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Rests on an assumption: Air travel faces different and more challenging operating conditions than other fuel uses.
The paper relies on this without support.
The need for sustainable aviation is undeniable.
“The need for sustainable aviation is undeniable as it is expected that the sector will occupy an increasingly prominent position in global transportation.”
The paper relies on this without support.
Sustainable fuels will play an important role in the transition to carbon neutrality.
“Sustainable fuels will play an important role in this transition.”
The paper relies on this without support.
Air travel faces different and more challenging operating conditions than other fuel uses.
“Due to the different and more challenging operating conditions faced by air travel”
The paper relies on this without support.
The particularities of air travel make the specification for approval and use of additives more complex.
“due to the particularities of air travel, specification regarding approval and use of additives is more complex”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“biodiesel could not be used as jet fuel, given its reduced energy density and high freezing point [60].”
From Assessing the future prospects of emerging technologies for shipping and aviation biofuels: A critical review (2024) · cites this paper as [60]
Citations
Cites
Chisti, Y. (2007) · Biotechnology Advances · doi:10.1016/j.biotechadv.2007.02.001 · Cited by 9,524
Buttler, A., & Spliethoff, H. (2018) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2017.09.003 · Cited by 2,510
A Process for Capturing CO2 from the Atmosphere
Keith, D. W., Holmes, G., St. Angelo, D., & Heidel, K. (2018) · Joule · doi:10.1016/j.joule.2018.05.006 · Cited by 1,910
Daza, Y. A., & Kuhn, J. N. (2016) · RSC Advances · doi:10.1039/c6ra05414e · Cited by 626
Baroutaji, A., Wilberforce, T., Ramadan, M., & Olabi, A. G. (2019) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2019.02.022 · Cited by 592
Lee, R. A., & Lavoie, J.-M. (2013) · Animal Frontiers · doi:10.2527/af.2013-0010 · Cited by 571
Singh, A., & Olsen, S. I. (2011) · Applied Energy · doi:10.1016/j.apenergy.2010.12.012 · Cited by 471
Roberts, A., Brooks, R., & Shipway, P. H. (2014) · Energy Conversion and Management · doi:10.1016/j.enconman.2014.03.002 · Cited by 425
Aviation biofuel from renewable resources: routes, opportunities and challenges
Kandaramath Hari, T., Yaakob, Z., & Binitha, N. N. (2015) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2014.10.095 · Cited by 423
Drop-in fuels from sunlight and air
Schäppi, R., Rutz, D., Dähler, F., Muroyama, A., Haueter, P., Lilliestam, J., Patt, A., Furler, P., & Steinfeld, A. (2022) · Nature · doi:10.1038/s41586-021-04174-y · Cited by 411
Research works printed but not linked: 4
- United Nations (December, January 30). Framework Convention on Climate Change. Adoption of the Paris Agreement. Proceedings of the 21st Conference of the Parties, Paris, France.
- United Nations (November, January 31). International Aviation Climate Ambition Coalition. Proceedings of the 26th United Nations Climate Change Conference, Glasgow, UK.
- Chevron (2007). Aviation Fuels: Technical Review, Chevron.
- Roberts, W.L. (2008, January 7). Bio jet fuels. Proceedings of the 5th International Biofuels Conference, New Delhi, India.
Cited by
Sorted by citations
Hydrogen-powered aircraft: Fundamental concepts, key technologies, and environmental impacts
Adler, E. J., & Martins, J. R. R. A. (2023) · Progress in Aerospace Sciences · doi:10.1016/j.paerosci.2023.100922 · Cited by 397
RETRACTED: Sustainable hydrogen energy in aviation – A narrative review
Yusaf, T. F., Mahamude, A. S. F., Kadirgama, K., Ramasamy, D., Farhana, K., Dhahad, H. A., & Talib, A. R. A. (2023) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2023.02.086 · Cited by 307
RetractedWang, B., Ting, Z., & Zhao, M. M. (2024) · Carbon Capture Science & Technology · doi:10.1016/j.ccst.2024.100263 · Cited by 168
Emerging technologies, policies and challenges toward implementing sustainable aviation fuel (SAF)
Lau, J. I. C., Wang, Y. S., Ang, T. J. N., Seo, J. C. F., Khadaroo, S. N. B. A., Chew, J. J., Lup, A. N. K., & Sunarso, J. (2024) · Biomass and Bioenergy · doi:10.1016/j.biombioe.2024.107277 · Cited by 147
A recent review of aviation fuels and sustainable aviation fuels
Qasem, N. A. A., Mourad, A., Abderrahmane, A., Said, Z., Younis, O., Guedri, K., & Kolsi, L. (2024) · Journal of Thermal Analysis and Calorimetry · doi:10.1007/s10973-024-13027-5 · Cited by 121
Metadata
- Authors
- Cabrera, E., & de Sousa, J. M. M.
- Affiliations
- Instituto Superior Técnico (PT)
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
- Venue
- Energies
- Publisher
- MDPI AG
- Published
- 2022-03-26
- Volume
- 15
- Issue
- 7
- Pages
- 2440
- ISSN
- 1996-1073 (ISSN-L)
- OpenAlex
- W4221122404
- Cited by
- 217
- References
- 41
- Citations by year
- 2026: 51 · 2025: 67 · 2024: 54 · 2023: 36 · 2022: 8
- FWCI
- 16.44
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Energies (publishedVersion, cc-by)
- RePEc: Research Papers in Economics (submittedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Fundação para a Ciência e Tecnologia (UIDB/50022/2020)
- Topics
- Physical Sciences › Engineering › Aerospace Engineering › Advanced Aircraft Design and Technologies
- Physical Sciences › Engineering › Computational Mechanics › Heat transfer and supercritical fluids
- Social Sciences › Economics, Econometrics and Finance › General Economics, Econometrics and Finance › Aviation Industry Analysis and Trends
- Keywords
- sustainable aviation fuel, biofuels, synthetic fuels, hydrogen aviation, aircraft emissions reduction, technology readiness, fossil fuel dependence
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-10-10, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-10-10 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
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