Sustainable Aviation Fuels: A Review of Current Techno Economic Viability and Life Cycle Impacts

Abstract

Australia has set a new climate target of reducing emissions by 62–70% below 2005 levels by 2035, with sustainable aviation fuel (SAF) central to achieving this goal. This review critically examines techno-economic analysis (TEA) and life cycle assessment (LCA) of Power-to-Liquid (PtL) electrofuels (e-fuels), which synthesize atmospheric CO₂ and renewable hydrogen (H₂) via Fischer-Tropsch (FT) synthesis. Present PtL pathways require ~0.8 kg of H₂ and 3.1 kg of CO₂ per kg SAF, with ~75% kerosene yield. While third-generation feedstocks could cut greenhouse gas emissions by up to 93% (as low as 8 gCO₂e/MJ), real world reductions have been limited (~1.5%) due to variability in technology rollout and feedstock variability. Integrated TEA–LCA studies demonstrate up to 20% energy efficiency improvements and 40% cost reductions, but economic viability demands costs below $3/kg. In Australia, abundant solar resources, vast transport networks, and supportive policy frameworks present both opportunities and challenges. This review provides the first comprehensive assessment of PtL-FT SAF for Australian conditions, highlighting that large-scale development will require technological advancement, feedstock development, infrastructure investment, and coordinated policy support.

1. Introduction

Since the advent of the industrial revolution, there has been a notable escalation in the utilization of fossil fuels, resulting in atmospheric carbon dioxide concentrations exceeding 400 parts per million (ppm) and perpetuating climate change issues [1,2]. In light of this, a total of 175 nations formalized their commitment to the Paris Agreement in 2016, which aims to constrain global temperature increases to 1.5 °C through a comprehensive reduction of emissions across all sectors by 43% by the year 2030 [3,4]. Although road transport continues to be the predominant source of emissions within the transportation sector, both the aviation and maritime industries also significantly contribute to overall emissions [5,6]. Following the pandemic, the commercial air travel sector has experienced a resurgence, with an anticipated growth rate of 3.6% annually through 2042, thus underscoring the critical necessity for decarbonization strategies in these challenging sectors [7,8]. The aviation sector, integral to global transportation and commerce, nonetheless casts a considerable environmental impact through its carbon emissions [9,10], as it directly releases carbon dioxide into the atmosphere. Consequently, there exists a pressing need for innovative solutions that reconcile the operational demands of the industry with the ecological integrity of the planet [11,12]. Attaining net-zero emissions within the aviation sector necessitates the utilization of exclusively Sustainable aviation fuel (SAF) adoption, demanding dramatic production increases of 57% annually through 2030, succeeded by a sustained growth rate of 13% per annum from 2030 onwards [13].

The decarbonization efforts within the aviation sector are being navigated through multiple technological trajectories, each characterized by unique attributes concerning readiness, cost implications, and operational ramifications [14,15]. These advancements are increasingly pivotal as the aviation industry endeavours to explore all feasible avenues toward sustainability, such as the implementation of electrification technologies and hydrogen propulsion systems for short-haul flights as alternatives to conventional carbon-intensive methods [16,17]. SAF is the only near-term, long-distance commercial drop-in solution compatible with existing aircraft, with the potential to reduce lifecycle GHG emissions by up to 86% [18,19]. Notwithstanding, its scalability is predicated on factors such as availability, economic viability, and the considerable primary energy demands associated with its production. Fundamentally, the sustainability of SAF is contingent upon a closed-loop carbon cycle, wherein the carbon dioxide emitted during fuel combustion is demonstrably sequestered from the atmosphere during its synthesis [13,20].

Large-scale commercial deployment in aviation depends on transformative advancements in energy density, which are anticipated to emerge after 2040–2050 [21,22]. SAF is emerging as the most practical pathway for the decarbonization of commercial aviation in the short to medium term (2025–2050), providing immediate drop-in compatibility with existing aircraft and airport infrastructure while achieving a lifecycle CO₂ reduction of 70–85%, through advanced biofuel and synthetic fuel production methodologies [23,24]. Although battery electric propulsion holds long-term promise, the current limitations of lithium-ion technology providing only 250–300 Wh/kg compared to aviation fuel’s ~12,000 Wh/kg severely restrict its use to short-haul flights under 500 km and urban air mobility. This inadequate gravimetric energy density means that, before 2050, battery-electric propulsion will remain viable only for niche applications such as urban air mobility or ultra-short regional routes [25,26,27]. Hydrogen-powered aviation faces formidable near-term barriers, including the need for complete aircraft redesigns to accommodate cryogenic storage at −253 °C [28], extensive airport infrastructure upgrades with global transition costs exceeding $1.4 trillion, and unresolved safety risks arising from hydrogen’s wide flammability range and low ignition energy. While hydrogen propulsion offers long-term potential for carbon emission reductions, substantial technical, economic, and safety issues must be resolved first. These include cryogenic storage requirements, fire hazards, and large-scale infrastructure development. Furthermore, fuel cell aircraft currently incur operational costs up to 30% higher and consume more fuel than conventional aircraft due to persistent technological limitations [21,29,30,31,32,33].

The deployment of SAFs is currently the most effective strategy for reducing carbon emissions in the aviation sector [34,35,36], primarily because they can be used within existing aircraft and airport infrastructure without major modifications. Depending on the feedstock and production pathway, SAFs can achieve up to an 85% reduction in life-cycle GHG emissions [37,38,39,40]. They can be produced from a diverse range of renewable and waste-derived feedstocks, including lipids, municipal solid waste, agricultural residues, and captured CO₂ [41,42]. using certified conversion technologies such as Fischer Tropsch synthesis (FT-SPK, FT-SPK/A), alcohol-to-jet (ATJ-SPK), catalytic hydrothermolysis jet (CHJ), and synthetic iso-paraffins (SIP) [43,44]. Figure 1 illustrates the general production process of SAF.

Given their ASTM certification, feedstock flexibility, and compatibility with existing aviation infrastructure, SAFs are positioned as the critical bridging solution toward net-zero targets, enabling meaningful emissions reductions while battery-electric and hydrogen propulsion technologies mature [45]. By contrast, hydrogen and electric aircraft face 30–40% aerodynamic efficiency penalties and 40–70% increases in operational costs, making large-scale adoption economically and technically unfeasible in the next two decades [46,47]. Current SAF scale up efforts, reinforced by policy measures such as the EU’s ReFuelEU Aviation mandatewhich requires 70% SAF integration by 2050 [46,48,49], and similar global commitments, will be central to decarbonizing aviation until alternative propulsion technologies overcome their inherent limitations [22,50].

Among SAF production pathways, the PtL route produces SAF by synthesizing hydrocarbons from renewable hydrogen and captured CO₂, offering a pathway toward near-carbon-neutral fuels. Unlike bio-based routes, PtL is not limited by biomass availability, enabling large-scale deployment wherever renewable electricity and CO₂ sources are accessible, while delivering drop-in fuels fully compatible with existing aviation infrastructure [51]. In the PtL process, proton exchange membrane (PEM) and alkaline electrolyzers use renewable electricity to split water (H₂O) into hydrogen (H₂) and oxygen (O₂) [52]. Carbon dioxide can be sourced either from industrial point sources or directly from the atmosphere via direct air capture (DAC). The Reverse Water–Gas Shift (RWGS) reaction then converts H₂ and CO₂ into carbon monoxide (CO), which is fed into a Fischer–Tropsch (FT) synthesis reactor to produce synthetic hydrocarbons [53]. Such processes are essential for achieving deep carbon reductions and advancing the environmental performance of the transportation sector. Beyond lowering lifecycle emissions [54]. SAFs also reduce particulate matter emissions, improving air quality and mitigating health risks associated with aviation [55]. They can help stabilize fuel costs by reducing dependence on volatile oil markets and support economic growth through job creation in regions involved in feedstock supply and processing [56,57]. However, large-scale PtL deployment requires substantial CO₂ sourcing [58]. By 2050, global e-fuel production is projected to require approximately 6.1 Gt of CO₂ annually far exceeding the estimated 2.8 Gt available from point sources [59,60]. This shortfall underscores the critical need to combine point-source CO₂ capture with DAC to scale e-fuel production [61,62]. Ultimately, SAFs, and particularly PtL-derived fuels, offer a compelling route toward a cleaner, more sustainable, and economically resilient aviation sector.

Multiple techniques and pathways exist for producing synthetic SAF, each with distinct chemical reactions and process routes. Aviation fuels can be grouped into synthetic fuels, biofuels, and traditional jet fuels. Each has its own set of attributes that impact their performance and the environment [63]. A well-established supply chain exists for conventional jet fuels derived from crude oil, although their production generates substantial GHG emissions [64]. In contrast, biofuels are produced from sustainable biogenic resources, which can significantly reduce GHG emissions across their entire life cycle. However, biofuel production may compete with food crops and land use and often requires long growth periods. SAF, while promising, faces challenges related to scalability and cost. Generally, feedstocks such as biomass are insufficient to meet the aviation industry’s large-scale demand, and agricultural sources risk competing with food production. The PtL pathway and other synthetic technologies convert captured CO₂ into aviation fuel [65], offering the potential to further reduce carbon intensity and lessen reliance on biomass feedstocks. Synthetic fuels particularly those produced using renewable energy can substantially lower greenhouse gas emissions while minimizing competition with food crops [66]. However, their production is highly energy-intensive and economically viable only when abundant, low-cost renewable energy is available [67].

As the aviation industry seeks to reduce its environmental footprint, SAF has emerged as a key solution [21,68]. Among the production methods, synthetic e-fuels created by combining hydrogen with captured CO₂ offer promising potential. These fuels can be evaluated using two essential analytical frameworks: technoeconomic analysis (TEA) and life cycle assessment (LCA), which help determine their feasibility and environmental impact [69]. Despite growing interest and development, SAF still faces considerable challenges. Figure 2 presents the United Nations Sustainable Development Goals (UNSDGs) provide a comprehensive roadmap for addressing the global need for long-term, sustainable energy solutions [70]. As illustrated in Figure 2, several SDGs can be directly advanced through the application of LCA and TEA to e-fuel production via the Fischer Tropsch (FT) pathway. The caption within the figure stresses the need for energy that is affordable, reliable, and clean, and mentions the use of resources to produce e-fuel via the PtL derived FT pathway as a sustainable solution. It is always challenging to make sure that feedstock is accessible, set up cost-competitive manufacturing, and meet tight certification standards, such those specified by ASTM International for the use of SAF in commercial aircraft [71]. A notable innovation comes from the U.S. startup Aircela, which has developed a mini device that converts air and water into usable fuel. This system, powered by renewable energy and based on direct air capture (DAC) based PtL, is designed for easy deployment in homes, businesses, and industrial facilities. Now is a critical time to consider both the opportunities and challenges facing SAF particularly those derived from CO₂ as technological innovation and policy frameworks continue to evolve. On World Environment Day, 5 June 2025, the Australian Defence Force (ADF) reaffirmed its commitment to national climate goals, pledging to reduce emissions by 43% by 2030 and achieve net zero by 2050 through a series of impactful programs.

Figure 3 illustrates the emissions reduction pathway for achieving the International Air Transport Association (IATA) target for CO₂ mitigation [72]. Meeting this objective requires a multifaceted approach, including the development and deployment of SAFs, the implementation of carbon offsets and carbon capture and storage (CCS), the advancement of novel technologies such as electric and hydrogen-powered aircraft, and enhancements in infrastructure and operational efficiency [73]. While the substitution of fossil fuels with SAFs has the potential to significantly reduce CO₂ emissions, it is not sufficient on its own to GHG emissions entirely. LCAs have shown that although SAFs exhibit a lower global warming potential (GWP) compared to conventional jet fuels, their impact remains positive. Consequently, carbon offsets and CCS are essential to address the residual emissions that persist even with widespread SAF adoption [74]. Figure 3 delineates the anticipated contributions of various mitigation strategies towards the attainment of net-zero emissions by the year 2050. Sustainable Aviation Fuel (SAF) is recognized as the preeminent contributor, representing 65% of the overall mitigation potential. Following this, carbon capture technologies contribute 19%, the implementation of new technologies, including advanced aircraft designs and propulsion systems, accounts for 13%, while operational enhancements yield a contribution of 3% [75].

Table 1. Properties of e-fuels produced from various pathways vs. fossil fuels from conventional productions *.

Properties	E-Fuels								Fossil Fuels
	FTD	FTG	MtG	FTK	MtJ #	DME	OME	MCH	Gasoline	Diesel	Kerosene	LPG
Density (kg/m3)	765–845	720–755	720–755	730–770	730–770	gas	961–1100	792	715–780	815–855	780–810	540 (at bar)
Boiling point (°C)	85–360	210 (FBP) **	210 (FBP) **	205–300	205–300	−24.8	105–280	65	22–215	170–380	151–301	−41 to −0.5
LHV (MJ/l)	33.1–34.3	30–33	30–33	-	-	18.3–19.3	19.5–19.7	15.4–15.6	31.2–32.2	35.3–36	35.3	24.8
Octane number	-	Upto 85	Upto 85	-	-	-	-	110–112	90–95	-	-	105–115
Cetane number	70–80	-	-	-	-	Upto 55	63–110	5	-	45–33	-	-
Miscibility	Diesel	Gasoline	Gasoline	Jet fuel	Jet fuel	LPG	Diesel	Gasoline, Diesel

* Form [77,78,79]. # Methanol to Jet (MtJ) & Final Boiling Point (FBP) **.

summarizes the differences between fossil fuel and e-fuel’s properties. It delineates the comparative analysis of the fundamental characteristics of e-fuels in juxtaposition with conventional fossil fuels. E-fuels, encompassing FTD, FTG, MtG, FTK, MtJ, DME, OME, and MCH, exhibit a range of densities (from gaseous states to 1100 kg/m³) and extensive variations in boiling point ranges, contingent upon the specific fuel type; conversely, fossil fuels such as gasoline, diesel, kerosene, and LPG are characterized by more confined conventional ranges. The lower heating values (LHV) of e-fuels are typically analogous to or marginally inferior to those of fossil fuels, with the exception of DME, OME, and MCH, which present diminished energy densities. The octane and cetane numbers demonstrate considerable variability: certain e-fuels (for instance, OME and MCH) possess exceptionally high octane ratings, whereas others, such as FTD, exhibit elevated cetane values. The miscibility characteristics also diverge, with e-fuels corresponding to particular fossil fuel analogs (for example, FTD aligns with diesel, while FTK corresponds with jet fuel). The chart elucidates the diverse physicochemical properties inherent in e-fuels, thereby affirming their potential as viable alternatives for a variety of fossil fuels in transportation and energy sectors.

Following Japan’s confirmation of two primary SAF production pathways lipid-based hydroprocessed esters and fatty acids (HEFA) and alcohol-to-jet (AtJ) as its main national SAF strategies, Australia is also adopting these two pathways as key national priorities, as outlined in the recently released Asia-Pacific (APAC) Low Carbon Fuels and CCUS Summit White Paper [80]. HEFA fuels, derived from renewable sources such as vegetable oils, can readily replace conventional jet fuels. Fischer Tropsch synthetic kerosene (FTSK), produced from natural gas or biomass, offers high energy density but remains expensive and technically challenging to manufacture. ATJ fuels, produced from renewable alcohols such as ethanol, can help reduce particulate emissions, though they may compete with feedstocks [81]. Biomass-to-liquid (BtL) SAFs from lignocellulosic materials hold promise, but their production must become more scalable and cost-effective [82]. Power-to-liquid (PtL) SAFs, synthesised from renewable electricity and captured CO₂, avoid land competition but require further technological advancements to reduce costs [83].

The existing SAF literature reveals significant methodological and geographic limitations that have hindered comprehensive understanding of production viability, particularly within the Australian context. Previous research has predominantly concentrated on North American and European frameworks, with minimal Australia-specific investigation [84], creating a substantial knowledge gap for Australia’s distinctive renewable energy landscape and extensive transportation infrastructure. Most existing studies have relied on national or global averages rather than employing high-resolution spatial analysis, thereby undermining their relevance for regional policy development [85]. These geographic biases are compounded by critical methodological deficiencies that permeate the field: limited integration of geospatial TEA-LCA frameworks despite their demonstrated effectiveness in US case studies; insufficient utilization of primary process data with over-reliance on secondary databases [86]; absence of multi-criteria decision frameworks that adequately combine environmental, economic, and social objectives [87]; and inadequate treatment of uncertainty and sensitivity analyses across both TEA and LCA dimensions.

PtL technology assessments have particularly under-explored critical system dependencies, including electricity sourcing variability, direct air capture capital costs, and regional water resource requirements, with most studies remaining confined to single-case analyses without systematic comparison of renewable energy integration options such as offshore versus onshore systems or grid-connected versus dedicated renewable installations. The literature consistently lacks temporal dynamics modeling, failing to capture seasonal feedstock yield variations, hourly energy supply fluctuations, and long-term land-use trajectory implications, while frequently excluding flight-level operational differences and short-lived climate forcers that bias mitigation estimates for specific routes and fleet operations [88]. Most critically, no comprehensive, spatially-resolved national TEA-LCA synthesis exists for Australia despite identified production potential [89], leaving value-chain constraints including port infrastructure capacity, industrial cluster development, water availability, and regulatory frameworks unquantified compared to their international counterparts [90]. This research addresses these fundamental gaps by providing the first comprehensive, quantitative assessment of PtL derived FT SAF viability specifically tailored to Australian conditions, incorporating advanced geospatial analysis, integrated TEA-LCA methodology, and region-specific renewable energy resource evaluation.

This review provides an update outlining a variety of issues of the development and use of SAF with two main goals to (1) synthesize existing knowledge on SAFs into a coherent overview of the field, and (2) examine the technical, economic, and environmental challenges that currently hinder their widespread adoption. The study wants to start a more educated and nuanced global discourse about the future of SAFs by looking at these things. The review also talks about distinct regional strategies and the issues and solutions that have been found in different parts of the world. A lot of the research that has been done so far has looked at only one part of sustainable fuel, such how to get the raw materials or how to make the fuel. However, there are still not enough studies that look at all these factors together and how they affect each other.

2. SAF Development in Australia

For Australia vast, remote, and geographically isolated aviation is not a convenience but a lifeline, and often the only viable connection to the rest of the world. Aviation is part of its national security and infrastructure because it connects its scattered population and makes it possible for important services like transporting people and goods, responding to emergencies, evacuating sick people, and protecting the country. It also has a big impact on the economy because it helps tourism, trade, and business [91]. Given this reliance, decarbonizing aviation is a national priority, and SAFs offer the most immediate and scalable pathway to maintain connectivity while significantly reducing GHG emissions, responsible for 2.5% of global carbon emissions, faces challenges as passenger demand and fuel consumption are projected to rise sharply in Australia, with domestic emissions doubling from 1990 to 2019 and fuel demand expected to grow by 75% by 2050 [48,92].

Figure 4 illustrates SAF activities across the Asia Pacific (APAC) region. Singapore and Japan are emerging as key SAF refining hubs, relying primarily on imported feedstocks. Meanwhile, major agricultural producers such as China, Malaysia, and Thailand are positioning themselves to lead in feedstock supply while also expanding their refining capabilities [93]. For Australia, developing a domestic SAF industry is both a strategic necessity and an opportunity to enhance environmental and economic resilience [94]. At present, approximately 90% of Australia’s liquid fuels including aviation jet fuel are imported, creating a heavy dependence that heightens exposure to geopolitical instability and supply chain disruptions, while contributing to more than 14% of the nation’s total carbon emissions [90].

Australia’s unique geography an isolated continent with no land borders and a widely dispersed population makes aviation indispensable for domestic connectivity, international trade, emergency response, and national sovereignty. The APAC region offers distinct advantages for SAF production, and Australia is well-placed to capitalise on them. The country possesses abundant solar resources for renewable energy generation [95], substantial feedstock availability from agricultural waste, municipal residues, and canola (much of which is currently exported), as well as surplus biomass. These factors position Australia to scale SAF production efficiently across its diverse states and territories.

Australia has strong potential to meet a substantial share of its jet fuel demand with domestic feedstocks and emerging conversion technologies potentially supplying 60% of demand by 2025 and up to 90% by 2050 through expanded biogenic resources and hydrogen production [96]. The federal government, primarily through the Australian Renewable Energy Agency (ARENA), has funded feasibility studies for bio-refineries using sugarcane waste in Queensland, as well as infrastructure trials at Brisbane Airport. Parallel private-sector investment is also advancing: HAMR Energy is assessing a methanol-to-SAF plant in South Australia/Victoria that could produce 125 million litres annually by 2030, generating significant employment and regional economic benefits [97]. Major airlines, fuel suppliers, and airports—including Qantas, Virgin Australia, Ampol, and Sydney Airport are calling for federal regulation and investment incentives to accelerate domestic SAF production. Economic modelling suggests that replacing feedstock exports with value-added local SAF production could add $13 billion to GDP and create thousands of jobs by 2040 [94].

Figure 4. Biofuels and SAF Activities Across Asia and Oceania (APAC) [96]. The map highlights country-level engagement in biofuels and SAF, showing feedstock types and activity status across four categories: Other Biofuels, Feedstock Activity, SAF Policy and Activity. Countries are ranked as Developed, Developing, or Undeveloped based on industry maturity and strategic progress.

Figure 4. Biofuels and SAF Activities Across Asia and Oceania (APAC) [96]. The map highlights country-level engagement in biofuels and SAF, showing feedstock types and activity status across four categories: Other Biofuels, Feedstock Activity, SAF Policy and Activity. Countries are ranked as Developed, Developing, or Undeveloped based on industry maturity and strategic progress.

Australia’s demand for aviation fuel and the number of air passengers is expected to grow substantially in the coming decades, driving a corresponding rise in GHG emissions. Between 1990 and 2019, domestic aviation emissions doubled, and by 2050, fuel demand is projected to increase by 75% [94]. This trend underscores the urgent need for low-carbon alternatives such as SAF. Australia possesses a diverse range of feedstocks for SAF production, spanning both biogenic sources and PtL pathways. However, at present, SAF is available only on flights departing from airports with dedicated supply. Developing domestic biorefineries and the supporting supply chains would not only strengthen Australia’s energy security but also create employment across rural and urban areas advancing the nation’s broader goals of economic growth and a low-carbon transition.

Figure 5 illustrates the potential volume of jet fuel that could be produced from various feedstocks in Australia, compared against the projected national demand. The dashed line represents projected jet fuel demand, which is expected to rise steadily over the next 25 years, remaining well above the total potential production from available feedstocks for most of the period. While all feedstock categories residues, carbohydrates, waste, and oilseeds are projected to grow only gradually, the PtL pathway stands out as the dominant growth driver. PtL production capacity is projected to expand dramatically, from under 6000 ML in 2025 to nearly 14,000 ML by 2050, positioning it as the key technology for closing the supply demand gap. This reflects both the scalability of PtL when powered by abundant renewable energy and its independence from biomass feedstock limitations. Australia’s diverse resource base including agricultural residues, municipal waste, oilseeds, and abundant renewable electricity provides a strong foundation for SAF production. With targeted policy support, infrastructure investment, and industry partnerships, Australia could meet a substantial share of its jet fuel needs domestically by 2050. This shift would significantly reduce reliance on imported fossil jet fuel, enhance national energy security, and contribute to deep decarbonisation of the aviation sector.

The economic viability of different SAF production pathways is heavily influenced by feedstock availability, market trends, and technological maturity. Feedstock exports and prices are fluctuating, driven by increasing SAF investments and government policies abroad, which risk diverting resources away from domestic refining opportunities. Figure 6 shows the projected levelized cost of production for five major feedstocks. In the near term, biogenic SAF derived from sources such as vegetable oil and biomass offers the most cost-effective option before 2030. However, its price trajectory flattens thereafter, leaving little room for further reductions and exposing it to volatility from global demand shifts. Advances in fermentation technologies could reduce ethanol costs and help lower biogenic SAF prices, but these methods introduces trade-offs, such as longer production times, and still offer limited cost-reduction potential after 2024. By contrast, PtL SAF pathways, while initially more expensive at over $4.0/L in 2023, is projected to become increasingly competitive as the hydrogen economy becomes more mature and renewable energy costs fall. For example, PtL SAF production costs could approach $2.0/L∙bar by around 2045. In summary, biogenic feedstocks provide an immediate but constrained short term solution, whereas PtL represents a longer-term pathway with greater scalability for large-volume SAF production.

3. SAF Production Pathways

3.1. ASTM-Approved SAF Pathway

Carbon capture, utilization and storage (CCUS) is a widely investigated technology. Despite being established in the scientific community for almost three decades, its high investment and operating expenses make growth and industrial adoption challenging [98]. Thus, research is concentrating on Carbon Capture and Utilization (CCU) as an alternative to justifying the high capital expenditure of CO₂ capture, which is viewed as a feedstock for the synthesis of chemicals and fuels [99]. CCU is known as PtL for the process of producing liquid hydrocarbons. The raw hydrocarbon mixture is upgraded and refined to meet aviation fuel specifications, including those outlined by ASTM D7566 [100]. That need to be upgraded or converted to attain aviation fuel required properties [54,72,101].

The ASTM approved pathways form the foundation for producing drop in SAF that can be blended seamlessly with conventional jet fuels. At present, blends are limited to 50 vol%, though the industry is gradually moving toward higher proportions, with some future technologies expected to enable 100% SAF use.

Table 2. ASTM-approved SAF pathways *.

Pathway	Description	Feedstock	Blend Limit and (Year)	Energy Efficiency	Conversion Efficiency	Advantages	Challenges	FRL TRL	Accreditation
FT Synthetic Paraffinic Kerosene (FT-SPK)	Via FT, converting CO and H2 into LCHs.	Biomass, coal, natural gas	50% (2009)	50%	40–50%	feedstock versatility, potential for large scale production	high capital costs, feedstock preprocessing complexity	6–7 6–8	ASTM D7566 Annex A1
Fischer-Tropsch Synthetic Kerosene with Aromatics (FT-SPKA)	Like FT-SPK but includes synthetic aromatics to improve compatibility.	Biomass, coal, natural gas	50% (2015)	Like FT-SPK	Like FT-SPK	compatible with legacy aircraft systems; contains essential aromatics	still emerging; limited commercial application	6–7 6–8	ASTM D7566 Annex A4
Hydroprocessed Esters and Fatty Acids (HEFA-SPK)	Hydroprocessing technology to convert fats and oils into LCHs.	Bio-oil, animal fat, cooking oil, tallow	50% (2011)	65–70%	75–85%	high commercial maturity, compatibility with existing infrastructure, feedstock flexibility	limited feedstock availability, land-use concern	9 9	ASTM D7566 Annex A2
Alcohol-to-Jet (ATJ-SPK)	Converts alcohols to LCHs through dehydration, oligomerization, hydrogenation.	Alcohols like ethanol or isobutanol	50% Ethanol (2018); 30% Isobutanol (2016)	40–50%	40–50%	abundant alcohol feedstocks, uses existing infrastructure	low conversion efficiency, high scaling costs	7–8 7–8	ASTM D7566 Annex A5
Synthetic Iso-Paraffinic (SIP) Fuel from Hydroprocessed Fermented Sugar	Produced through biological fermentation of sugars into LCHs	Fermented sugars (sugarcane, corn, biomass)	10% (2014)	25–35%	20–30%	high purity product; low sulfur	high cost; low yield; limited scale-up	5–8 7–9	ASTM D7566 Annex A3
Catalytic Hydrothermolysis Jet (CHJ)	Converts lipids directly into SAF through catalytic hydrothermolysis	Lipid-rich biomass (oilseeds, algae)	50% (2020)	60%	60–70%	produces aromatics; drop-in fuel properties	early stage technology; limited demonstration	6–7 4–6	ASTM D7566 Annex A6
Hydrocarbons, Hydroprocessed Esters, and Fatty Acids SPK (HC HEFA-SPK)	Like HEFA but includes additional processing to convert fatty acids to LCHs	Lipid-rich oils (algae)	10% (2020)	Like HEFA	Like HEFA	Like HEFA	Like HEFA	6 5	ASTM D7566 Annex A7
Co-processed Biomass	Co-HEFA in a conventional petroleum refinery	Vegetable oil, animal fat, used cooking oil	5% (2018)	Like HEFA	Like HEFA	Like HEFA	Like HEFA	6–7 7–8	ASTM D1655 Annex A1
ATJ-SKA	ATJ derivative with the mixed alcohols	C2–C5 alcohols (Biomass)	50% (2023)	Like AtJ	Like AtJ	Like AtJ	Like AtJ	- -	ASTM D7566 Annex A8
Co-processed FT	FT hydrocarbons in a conventional petroleum refinery	co-processed with petroleum	5% (2020)	Like FT	Like FT	Like FT	Like FT	6–7 7–8	ASTM D1655 Annex A1
Co-processed HEFA	HEFA hydrocarbons co-processed with petroleum	Fats, oils, greases (FOG)	10% (2018)	Like HEFA	Like HEFA	Like HEFA	Like HEFA	- -	ASTM D1655 Annex A1
PtL	electrolysis, CO2 capture, synthesis	CO2, water, renewable electricity	50% (2011)	40–55%	40–50%	ultralow carbon intensity, CO2 recycling, renewable integration	high costs, energy-intensive, dependence on renewable sources	6–7 6–8	ASTM D7566 Annex A1

* Information from [13,36].

provides a concise overview of each pathway, outlining their feedstocks, blend limits, and a brief description of their production processes. By examining how different SAF pathways perform on short, medium, and long haul flights, it becomes possible to identify the conditions under which SAF delivers the greatest benefits and where alternative decarbonization strategies may be more effective [54,69,72].

SAF has strong potential for decarbonizing medium-haul routes, but its limited availability and the energy density constraints of current technology make it challenging to apply effectively on long haul flights. This raises important questions about the strategic allocation of scarce SAF resources, underscoring the need to prioritize deployment where they can deliver the greatest emissions reductions [102]. Building on these considerations, this research provides a detailed examination of the future of sustainable aviation, with a particular focus on how SAF and emerging propulsion technologies can work in tandem to enhance the sector’s long-term sustainability. Among these pathways, HEFA, FT, PtL and AtJ are the identified leading SAF technologies towards the targeted fuel transition of the aviation sector [103].

3.2. Power-to-Liquids (PtL)

Australia is well-positioned to become a global leader in PtL SAF production, thanks to its abundant renewable energy resources. Figure 7 illustrates the PtL pathway, in which renewable electricity, water, and captured carbon dioxide (CO₂) are converted into synthetic aviation fuels. Multiple chemical routes exist to transform hydrogen and carbon into jet-compatible fuels, each offering unique benefits, technical characteristics, and levels of commercial maturity.

The PtL process starts with producing renewable electricity, typically from offshore wind farms, large-scale solar photovoltaic arrays, or other clean energy sources. This electricity powers an electrolyser, which splits water into hydrogen and oxygen via electrolysis as

2H₂O → 2H₂ + O₂

Hereby producing H₂ for synthesis hydrocarbon fuel. The carbon component of the fuel is obtained using Direct Air Capture (DAC) technology, which extracts CO₂ directly from the atmosphere [67]. This step is crucial for achieving a closed carbon cycle. The captured CO₂ is reacted with the hydrogen through the Reverse Water-Gas Shift (RWGS) reaction to form carbon monoxide (CO): [66,67],

CO₂ + H₂ ⇌ CO + H₂O

The CO and H₂ mixture (syngas) [104] is fed into a Fischer–Tropsch (FT) reactor, where they are catalytically converted into liquid hydrocarbons (CxHy). The general FT reaction is:

nCO + (2n+1)H₂ → CnH2n + 2 + nH₂O

For example, methane and octane can be produced as

Methane (CH₄): CO + 3H₂ → CH₄ + H₂O

Octane (C₈H₁₈): 8CO + 17H₂ → C₈H₁₈ + 8H₂O

The raw FT hydrocarbons are then upgraded through processes such as hydrotreatment, hydrocracking, and isomerisation to meet aviation fuel quality and safety standards, including ASTM D7566. This ensures the final PtL SAF is fully compatible with existing aircraft engines and infrastructure.

The PtL technologies are already being advanced by a number of business and government projects in Australia. Funding for pilot-scale initiatives combining green hydrogen and CO₂ collection for the creation of synthetic fuel has been provided by the Australian Renewable Energy Agency (ARENA). For example, techno-economic frameworks for the establishment of PtL facilities close to CO₂ point sources and renewable energy hubs are being studied by the Future Energy Exports Cooperative Research Centre (FEnEx CRC) and its industry partners. Interest from the business sector is also rising at the same time. For instance, Wagner Corporation’s proposed $1.7 billion SAF refinery near Brisbane intends to show how waste and renewable resources can be converted on a large scale into aviation fuels [80]. While it is primarily focused on biomass at the moment, it indicates that the infrastructure is ready to integrate PtL modules in the future. Due to high capital costs for electrolyzers, CO₂ collection units, and synthesis reactors, as well as operating expenses associated with variable renewable power supply, PtL SAF is still costly internationally, usually four to eight times the price of fossil-based jet fuel. Nonetheless, levelized prices of PtL fuels are anticipated to decrease significantly over the next ten years due to the falling costs of solar and wind power as well as notable advancements in electrolyzer efficiency. There are many advantages of the PtL-FT Pathway such as, when powered by renewable energy, the PtL FT pathway can achieve near-zero carbon emissions, making it a viable option for decarbonizing the aviation sector [67]. The process achieves high conversion efficiencies, with carbon conversion efficiency at 88%, hydrogen conversion efficiency at 39.16%, and an overall Power-to-Liquids efficiency of 25.6% [68]. The resulting SAF is a drop-in fuel, meaning it can be used in existing aircraft engines and infrastructure without requiring significant modifications [69].

Furthermore, lifecycle assessment studies demonstrate that when powered exclusively by renewable energy sources and combined with atmospheric CO₂ capture, PtL SAF can reduce greenhouse gas emissions by up to 90–95% when compared to conventional jet fuels, meeting the strictest sustainability requirements under the ICAO CORSIA framework. For long-haul and international flights where electrification or hydrogen combustion are unlikely to be practical soon, the PtL pathway therefore provides a feasible long-term answer for profound decarbonization of aviation. Despite ongoing scientific and financial obstacles, Australia is a strong contender for the early implementation and expansion of PtL SAF technologies because to its combination of renewable resources, new legislative backing, industrial infrastructure, and academic know-how. The full potential of this approach will require cross-sector cooperation, strategic investment, and supporting regulatory frameworks to convert Australia’s plentiful solar and wind energy into a high-value, exportable, and climate-neutral aviation fuel.

Australia is uniquely positioned to lead PtL production. This process simultaneously tackles two major climate objectives: cutting aviation emissions and repurposing captured carbon into high–energy-density fuels. PtL pathways currently struggle to present affordable production costs, but projections for rapid reductions in hydrogen and green electricity prices form a promising future [103]. Recent advances such as more selective catalysts operating at lower temperatures, improvements in solid oxide electrolysis cells, and catalyst surface modifications are improving efficiency, lowering energy use, and increasing carbon conversion rates [79]. As a result, PtL pathway was highlighted at the most recent SAF APAC Summit 2025 (16–17 July 2025, Melbourne, Australia), where one of the four key themes “Future plans for SAF production and commercialisation” focused on e-fuels, PtL, and hydrogen. Discussions centred on advancing eSAF from innovation to deployment, supported by the creation of a standardised and enabling SAF framework.

3.3. Alcohol-to-Jet (AtJ)

The Alcohol-to-Jet (AtJ) category in ASTM-approved SAF pathways encompasses processes that convert alcohols primarily ethanol or iso-butanol into jet-range hydrocarbons through several unit operations, including dehydration, oligomerisation, hydrogenation, and fractionation [103]. The AtJ process chain can be broadly divided into three stages: thermochemical, biological, and thermocatalytic. In the first stage, bio-based feedstocks such as sugarcane, cassava, grains, and corn stover are converted into ethanol (EtJ) or butanol (BtJ) via fermentation or gasification. In contrast, the methanol-to-jet (MtJ) route produces methanol from renewable hydrogen and captured CO₂, or from syngas derived from biomass gasification [104]. Once the alcohols are obtained, they undergo a series of refining steps: dehydration to form olefins, oligomerisation to extend carbon chains, hydrogenation to produce paraffinic hydrocarbons, and fractional distillation to yield a jet fuel fraction meeting ASTM standards. Ethanol can also be synthesised directly from CO₂ and H₂ via specialised catalyst systems. Alternatively, methanol can be carbonylated to acetic acid, which is then hydrogenated to ethanol. Figure 8 shows the pathways for SAF and Renewable Diesel (RD) Production as Ethanol-to-Jet (EtJ), Butanol-to-Jet (BtJ), and Methanol-to-Jet (MtJ) routes. The flowchart illustrates biochemical and thermochemical routes from biomass and renewable energy (RE) to SAF and renewable diesel via fermentation, gasification, and alcohol-to-jet (AtJ) processes [103,104].

EtJ is currently the most commercially mature AtJ pathway. Leading technology providers include Honeywell UOP, Axens, Lummus Technology, LanzaJet, Byogy, and SAFFiRE Renewables. In 2024, LanzaJet commissioned the world’s first commercial-scale EtJ facility in Soperton, Georgia, with a capacity of 10 million gallons per year (MGPY). By 2025, global EtJ-based SAF capacity is projected to reach approximately 1.23 billion gallons annually [105]. BtJ remains less developed. KBR is the primary technology licensor, with Gevo and Swedish Biofuels spearheading commercialization. Gevo operates a 10 MGPY facility in Texas and is building a 55 MGPY SAF plant in South Dakota [106]. Swedish Biofuels is developing three plants in Sweden, each with a capacity of 130 MGPY. Global BtJ-based SAF capacity is expected to reach about 245 MGPY by 2025. MtJ is not yet ASTM-approved, unlike EtJ and BtJ, but is emerging as a promising addition to the AtJ technology family [69]. At the 28th UN Climate Change Conference (COP28), companies such as TotalEnergies and Masdar demonstrated the potential of methanol as an aviation fuel blendstock. Technology developers including Honeywell UOP, Axens, Topsoe, and ExxonMobil are adapting existing methanol synthesis and conversion platforms for MtJ production [107]. Projects led by Metafuels and SPIC aim to deliver approximately 4 MGPY by 2025 [107,108]. The MtJ process involves converting methanol to hydrocarbons via methanol-to-gasoline (MtG) or methanol-to-olefins (MtO) pathways, followed by oligomerization and hydroprocessing. Optimized catalytic systems can achieve 90–95% carbon conversion efficiency for methanol synthesis [109]. Due to its ease of storage, methanol offers better compatibility with intermittent renewable energy sources than hydrogen or syngas [86].

3.4. Comparison of the SAF Pathways

Hydroprocessed esters and fatty acids (HEFA) is the most established SAF pathway, benefiting from commercial readiness and direct drop-in compatibility with existing aviation fuel systems [110]. It can use various renewable oils and fats as feedstocks, ensuring relatively straightforward integration into current supply chains. However, its dependence on edible oils and animal fats raises concerns over food–fuel competition and indirect land-use change. Furthermore, the GHG savings are moderate compared to more advanced synthetic pathways, especially if the feedstocks are sourced unsustainably. Table 3 shows the advantages and disadvantages of different SAF pathways where, FT fuels offer versatility in feedstock use from biomass to natural gas and deliver high-quality, sulfur-free fuel compatible with current aviation infrastructure [111]. The process also enables deep carbon conversion into high-energy-density hydrocarbons. The downside lies in its high capital and operational costs, as well as significant energy requirements. Moreover, the GHG footprint depends heavily on the feedstock: coal- or natural gas based FT can be highly carbon-intensive unless paired with carbon capture.

AtJ can leverage multiple alcohol feedstocks such as ethanol, butanol, and methanol, some of which can be produced from renewable sources, offering potential for reduced particulate emissions in combustion [112]. While promising, AtJ faces feedstock competition with other sectors (e.g., transport fuels, chemicals) and is only beginning to achieve commercial scale [113]. This limits current market impact despite growing interest in pathways like ethanol-to-jet and methanol-to-jet. Biomass-to-Liquid (BtL) can utilize a wide variety of biomass, including lignocellulosic residues, offering the potential for sustainable feedstock sourcing and high-quality fuel output with low sulfur [114]. However, BtL is hindered by complex, multi-step processing that often requires substantial energy input, contributing to higher production costs. Commercial deployment remains limited, with projects mostly at the pilot or demonstration stage. Algae based SAF has unique advantages: cultivation on non-arable land, use of saline or wastewater, and very high biomass productivity [115]. It minimizes competition with food crops and can be a sustainable carbon sink. Yet, significant technical and economic barriers remain, including the cost of cultivation, harvesting, and lipid extraction. These challenges have kept algal SAF largely in the research and pilot phases.

PtL stands out for its capacity to produce truly carbon-neutral fuels when powered by renewable electricity and supplied with captured CO₂ [116]. It offers a clear long-term decarbonization pathway for aviation, free from biomass supply constraints. The key drawbacks are its high energy intensity, capital cost, and limited current scale. Infrastructure for large-scale renewable electricity and CO₂ capture will be critical to its growth.

Table 3. Summary of advantages and disadvantages of different SAF pathways from literature *.

SAF Pathway	Technology Maturity	Scalability Potential	GHG Reduction Potential	Production Cost Trend	Key Advantages	Key Limitations
HEFA	High (commercial)	Moderate (feedstock-limited)	Medium (40–70%)	Medium	Commercially available; drop-in fuel	Feedstock competition; limited GHG gains if unsustainable sourcing
FT Synthetic Kerosene	Medium (some commercial plants)	High (with sustainable feedstocks)	High (up to 90% with biomass + CCUS)	High	Flexible feedstocks; high-quality fuel	High CAPEX/OPEX; energy-intensive
AtJ (EtJ, BtJ, MtJ)	Low–Medium (early scale-up)	Medium	Medium–High	High	Can use multiple alcohol sources; low particulate emissions	Feedstock competition; limited current capacity
BtL	Low (pilot/demo)	High (abundant biomass)	High (up to 90% with residues)	High	Uses lignocellulosic waste; low sulfur	Complex process; high energy input
Algal Biofuels	Low (R&D/pilot)	High (non-arable land use)	High	Very High	Minimal land competition; high yield	High production cost; cultivation challenges
PtL	Low (demo projects)	Very High (renewables + DAC)	Very High (>90%)	Very High	No biomass limits; true carbon-neutral potential	High energy demand; expensive

* Information from [110,111,112,113,114,115,116].

Table 3. Summary of advantages and disadvantages of different SAF pathways from literature *.

SAF Pathway	Technology Maturity	Scalability Potential	GHG Reduction Potential	Production Cost Trend	Key Advantages	Key Limitations
HEFA	High (commercial)	Moderate (feedstock-limited)	Medium (40–70%)	Medium	Commercially available; drop-in fuel	Feedstock competition; limited GHG gains if unsustainable sourcing
FT Synthetic Kerosene	Medium (some commercial plants)	High (with sustainable feedstocks)	High (up to 90% with biomass + CCUS)	High	Flexible feedstocks; high-quality fuel	High CAPEX/OPEX; energy-intensive
AtJ (EtJ, BtJ, MtJ)	Low–Medium (early scale-up)	Medium	Medium–High	High	Can use multiple alcohol sources; low particulate emissions	Feedstock competition; limited current capacity
BtL	Low (pilot/demo)	High (abundant biomass)	High (up to 90% with residues)	High	Uses lignocellulosic waste; low sulfur	Complex process; high energy input
Algal Biofuels	Low (R&D/pilot)	High (non-arable land use)	High	Very High	Minimal land competition; high yield	High production cost; cultivation challenges
PtL	Low (demo projects)	Very High (renewables + DAC)	Very High (>90%)	Very High	No biomass limits; true carbon-neutral potential	High energy demand; expensive

* Information from [110,111,112,113,114,115,116].

4. Techno-Economic Evaluation (TEA) and Life Cycle Assessment (LCA)

Techno-Economic Assessment (TEA) and Life-Cycle Assessment (LCA) are essential tools for evaluating the feasibility and sustainability of various SAF production pathways. TEA provides insight into the economic viability of SAF technologies by analyzing costs, scalability, and market competitiveness, while LCA examines the environmental impacts across the entire fuel life cycle from feedstock sourcing to end use. Together, these assessments offer a comprehensive understanding of both the practical and ecological dimensions of SAF development, helping stakeholders identify the most promising pathways and make informed decisions that align with climate goals and industry standards.

More and more people are realizing that the Fischer Tropsch (FT) synthesis process, especially the Power-to-Liquid (PtL) pathway, is a viable and scalable solution to make Sustainable Aviation Fuel (SAF) and reduce carbon emissions in the aviation industry. When carbon dioxide from the air reacts with green hydrogen, which comes from renewable energy sources through electrolysis, this process makes liquid hydrocarbons. Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA) must be used together to provide a full picture of how viable and sustainable this new way of making fuel is. Technoeconomic research shows that Power-to-Liquid (PtL) Fischer-Tropsch (FT)-based fuel for sustainable aviation fuel (SAF) in Australia has a lot of potential but also a lot of problems to solve. The Direct Air Capture (DAC) unit’s high initial cost and ongoing running costs, largely because of energy needs, make it much less likely that Sustainable Aviation Fuel (SAF) production can be economically viable. In order for SAF to compete with fossil fuels, it needs a lot of money to make it worth it. The minimum selling price for jet fuel is expected to be £5.16/kg [66]. The global warming potential of 21.43 gCO₂eq/MJSAF shows that it has much less carbon emissions than regular jet fuels, as shown by life cycle analysis [67].

4.1. Techno-Economic Analysis (TEA)

TEA uses a quantitative way to look at how well the PtL process works technically and how feasible it is economically along its value chain. According to estimates, the cost of making PtL fuels ranges from AUD 1.50 to AUD 3.00 per liter, depending on the feedstock and technology used [67]. The main parts and properties of TEA are shown in

Table 4. Techno-Economic Analysis (TEA) of e-Fuel Production Pathways *.

Aspect	Component	Description	Estimated Cost Range	Impact on Final Cost	Current Barriers	Potential for Cost Reduction	Projected Trend (2025–2035)
Renewable Electricity	Source Type	Primary energy input (Solar, Wind, Hydro); cost varies by location	$30–$80 per MWh	High	High initial investment, geographic limitations	Decreasing due to technology advances, economies of scale	Projected 30–50% reduction in renewable electricity costs by 2035
CO2 Capture and Storage	Capture Method	Essential raw material (DAC, Point-source); cost depends on technology, CO2 purity	$80–$120 per ton CO2	Moderate	High cost of DAC, energy-intensive	R&D into efficient DAC, adoption of modular capture units	Cost expected to decrease as DAC scales up
Electrolysis for H2	Electrolysis Technology	Converts water to hydrogen; capital- and energy-intensive (PEM, Alkaline, SOEC)	$3.5–$7 per kg H2	High	Electrolyzer cost, electricity intensity	Improvements in electrolyzer efficiency, lifetime expansion	Cost of H2 projected to halve by 2035
Fuel Synthesis	Catalyst and Reactor Tech	Combines H2 and CO2 to form e-fuel; catalyst type and design affect cost/efficiency	$2–$5 per kg fuel	Moderate	High-cost catalysts, limited reactor scalability	Research in catalyst recycling, scalable reactors	High-performance catalysts could lower costs by 25%
Total e-Fuel Production Cost	Aggregated Cost	Combined expenses from each stage to produce 1 kg of e-fuel	$5.5–$15 per kg fuel	–	Competes with fossil fuel prices; high dependency on energy costs	System optimization, cost-effective scale-up	Projected cost parity with fossil fuels by 2035 with sufficient scale-up
Comparison with Alternatives	–	Cost competitiveness vs. traditional fuels (fossil fuels, hydrogen, biofuels)	$1–$3 per kg fossil fuels	Moderate	Currently less competitive without subsidies	Policy incentives, renewable energy subsidies	e-Fuels likely to gain competitiveness in aviation/marine sectors
Sensitivity Analysis	–	Assesses variable impacts (electricity price, CO2 efficiency, catalyst cost)	Varies by factor	High	Dependence on volatile electricity markets	Investment in low-cost electricity sources, efficient CO2 capture	Improved resilience with stable renewable prices and market evolution

* Information from [68,69,70,71,72,73,74,75,76].

as follows:

Capital Expenditures (CAPEX): This includes the first money spent on important parts including Fischer-Tropsch reactors, Direct Air Capture (DAC) systems, Alkaline Electrolysers, Proton Exchange Membrane (PEM) systems, gas purification units, and the infrastructure needed to improve or refine fuel. The cost of making Sustainable Aviation Fuel (SAF) is between 0.81 and 5.00 EUR/L, depending on how it is made. This is much more than the cost of fossil fuels [68]. The DAC unit is a key part of the PtL process, but it costs a lot of money to build [69]. To meet the needs of the aviation industry, switching to PtL fuels requires a lot of money to be spent on production facilities, which is anticipated to be several hundred million AUD [70]. Investing in renewable energy infrastructure is vital to lower costs of doing business and make the economy more stable. The fact that SAF costs at least 5.4 times more to make than fossil jet fuel makes it hard to make it economically viable [72]. Possible carbon credits and laws that encourage lower emissions help the economy stay strong in the long run, even when they cost more in the short term.

OPEX (Operating cost): Labor, CO₂ feedstock, maintenance, catalyst replacement, water for electrolysis and cooling, and electricity, which is the main cost driver, are all part of this set of continuing costs. The cost of energy, which powers the electrolyser, is the main factor that affects the OPEX for PtL FT-based SAF production. CO₂ capture, labor, and maintenance are other costs that come up while running a business. The cost of renewable energy is one of the main things that affects OPEX. Electricity in Australia may be cheap, especially when businesses use renewable energy sources on their own property because there are so many of them. The cost of using direct air capture equipment to store CO₂ is another major operational expense. But as DAC technology gets better, these expenses should go down over time.

Energy and Mass Balance: Find out the flow rates of hydrogen, carbon dioxide (CO₂), and hydrocarbons, as well as the energy needs at each stage. This includes energy losses across systems, the possibility of heat integration, and the stoichiometric ratios of syngas (H₂:CO). The balance of mass and energy is very important for figuring out how efficient the conversion process is. The solid oxide semi-closed CO₂ cycle can be up to 68.9% efficient in larger buildings [74]. Energy intake from renewable sources has a big effect on the whole energy balance and the sustainability of the fuel manufacturing process.

Levelized Cost of Fuel (LCOF): It is the average cost of making one unit of SAF (for example, USD/L or USD/GJ) across the plant’s operational life. It is based on CAPEX, OPEX, efficiency, and capacity factor. Technological progress and economies of scale may help cut costs [72]. The LCF is an important factor in determining if PTL FT fuel is economically viable. According to research, economies of scale and new technologies might greatly lower the LCF. In the best case, the cost of producing CO could drop to as low as 53 €/GJ [73].

Conversion efficiency: The term for how well energy inputs like CO₂ or electricity can be turned into fuel. This includes heat losses, the amount of energy used to directly capture air (kWh/kg-CO₂), the efficiency of the electrolyzer (kWh/kg-H₂), and the efficiency of Fischer-Tropsch synthesis. Conversion efficiency has a direct effect on how long it takes to get back the money spent on PTL FT technology. Investors are more likely to invest in technology that has shorter payback times since it is more efficient. For instance, the effectiveness of the SOS-CO₂ cycle makes it possible to have competitive power pricing, which can also be used in situations where fuel generation is needed.

The internal rate of return (IRR), payback time, and net present value (NPV): All are important ways to figure out how long PTL FT projects will last. A high IRR means that an investment is likely to be profitable, whereas a positive NPV means that expected profits will be greater than costs. Higher carbon prices can make renewable fuels more competitive, which makes PTL FT fuels more economically viable through carbon pricing. These financial measures are used to see if initiatives can work in different price and policy situations. Changes to policies and incentives are needed to make SAF production better and more profitable [73].

The size and capacity of the plant: It affect economies of scale and the payback period for capital expenditures. To lower the Levelized Cost of Energy (LCOE), you need a high capacity factor. To figure out how well the facility is doing economically, you need to know its size and capacity factor. Larger facilities have lower LCFs and better financial indicators because they benefit from economies of scale [74]. Capacity factors have an effect on operational efficiency, and bigger factors lead to better financial results.

Sensitivity analysis: How changes in important elements like power costs, electrolyzer costs, CO₂ capture efficiency, and catalyst life affect the LCOF and the project’s potential to make money. This helps finding the main ways to cut costs. Sensitivity analyses show that capital expenditures and operating hours are two important factors that affect LCF [75]. This shows how important it is to design plants well.

Carbon Intensity: To have emissions that are the same as those of conventional fuels, at least 84.6% of the energy must come from renewable sources [76]. Scenario modeling and policy integration are used to look at how carbon pricing, SAF blending rules, renewable energy subsidies, and tax breaks affect the finances of projects. Table 4 shows the aspects and properties of TEA for e-fuel production pathways.

4.2. Life Cycle Assessment (LCA)

LCA makes TEA better by looking at the environmental effects of PtL SAF over its whole life cycle, from getting the resources to burning the fuel. The PtL FT-based SAF manufacture is an excellent approach to cut down on the carbon footprint of flying, but it is still challenging to make it work economically. LCA reveals that PtL fuels can cut greenhouse gas emissions by a lot more than normal jet fuels over the course of their whole life. Using renewable energy sources might lower emissions by as much as 80%. New technology and rules need to be put in place to make enterprises more competitive because production costs are so high. The environmental advantages depend on using renewable energy sources, which highlights how crucial it is to use a mix of sustainable energy sources in the production process.

The Global Warming Potential (GWP): This tells how much greenhouse gases (CO₂e) are released during the whole life cycle, from burning fuel to running direct air capture (DAC) to making power upstream to refining. PtL technologies for generating SAF cut carbon emissions by more than half compared to fossil fuels [76]. When they come from renewable sources, PTL-FT fuels can lower lifecycle emissions by up to 80% compared to normal jet fuels [77].

Source of Energy: The cumulative energy demand (CED) is the total amount of primary energy needed to generate one unit of SAF. This comprises both direct and indirect energy sources, such as heating in FT reactors, compressing hydrogen, and DAC power. Using renewable energy sources to create power is what helps the environment the most. The LCA of PTL-FT e-fuels for Sustainable Aviation Fuel generation reveals that using renewable energy might considerably lessen the amount of pollution that planes produce in Australia.

Water footprint, Land Use and Resource Depletion: A lot of people don’t pay attention to how much water cooling and electrolysis consume, which is especially essential for regions like Australia that are dry. The water footprint and how resources are used are highly essential. The refinery’s need for cooling water is a big element of this [78]. Land Use and Resource Depletion looks at how mining and modifying land for things like electrolysers and other infrastructure influence the ecosystem. Making things takes a lot of energy, much of which comes from renewable sources. This could change how resources are used and how long they persist [79]. LCA employs data that is current, location-specific, and process-specific. It also looks at how the process will affect the environment in the long run.

Waste Management: Good waste management procedures are vital for making PtL in a way that has less of an impact on the environment [80]. It explains how to grant credits for waste heat or by-products and how to deal with operations that create more than one product, like naphtha or diesel. Air pollutants such NO_x, SO_x, CO, VOCs, and particulate matter are emitted during both the making and using of the product.

System boundaries: Finding the allocation and system boundaries is highly crucial since they determine how the LCA will be carried out. It’s challenging to compare research since the approach you chose has a large impact on the outcomes [81]. Different techniques of distributing resources, such as mass-based or energy-based methods, could result in different assessments of how they affect the environment. This means that you need to choose carefully to make sure that resource use and emissions are shown correctly.

Sensitivity analysis: It checks how trustworthy LCA conclusions are when the basic assumptions change, such as the grid’s makeup, how advanced the technology is, and how well it collects data. Sensitivity analysis looks at the things that have the most impact on the LCA outcomes. This enables you adjust how things are made and how resources are shared in precise ways [82]. Stakeholders may make sensible decisions about technical investments and policy initiatives for SAF development if they know how sensitive different aspects are.

Uncertainty analysis: The conclusions of a LCA are sometimes imprecise since the input data can change, such as the availability of feedstock and the efficiency of conversion. This uncertainty can have a large impact on how sustainable PtL FT fuel is [83]. Modeling things using real-world data can make things unclear. This highlights how crucial it is to have strict procedures for gathering and studying data to make LCA more accurate.

4.3. The Power-to-Liquid (PtL) Method for Generating SAF

Figure 9 highlights the technical and economic challenges of SAF production. A comprehensive assessment of PtL e-fuels requires integrating TEA and LCA. TEA evaluates economic feasibility by identifying cost barriers and proposing regulatory or investment measures to enhance production, while LCA ensures that these pathways deliver real environmental benefits consistent with climate goals. In the Australian context, techno-economic studies of PtL-FT SAF examine project costs, capital requirements, and overall viability, whereas LCA assesses environmental impacts. Together, these analyses indicate that PtL-FT fuels represent a promising alternative to conventional jet fuels, with the potential to significantly reduce carbon emissions while remaining compatible with existing aviation infrastructure.

Cost of producing alternative fuels, the availability of raw materials, and the speed of technological growth are just a few of the things that can make them economically and environmentally viable. It costs a lot of money to make SAF, especially PtL FT-based fuels, because it demands specialized technologies and infrastructure. Now, SAF isn’t as competitive in terms of price because it costs more to create than standard jet fuels. Investing in SAF manufacturing capacity is particularly crucial because the existing supply barely fulfills 0.1% of the demand for aviation fuel. Production needs to go higher to make a large difference in emissions [81]. Changing oil prices and the need to lower manufacturing costs make SAF less economically viable. The IATA says that SAFs, such PtL FT-based fuels, might lower emissions from planes by as much as 65% by 2050. Adding SAFs to existing infrastructure without making major changes to aircraft technologies makes them more affordable. SAFs are commercially viable since they can help the aviation sector attain its carbon neutrality targets and cut emissions over the course of their lives.

Sustainable aviation fuels (SAFs) emit significantly lower carbon emissions than conventional jet fuels, making them a critical pathway for aviation decarbonization. In particular, Power-to-Liquid Fischer–Tropsch (PtL–FT) fuels are attractive long-term options because they are derived from renewable energy sources. When produced from biomass-based or carbon-storing feedstocks, SAFs could even enable climate-neutral long-haul flights. However, their long-term success depends on the availability of renewable feedstocks and the efficiency of production methods. Current challenges—such as high production costs, limited feedstock access, and the need for advanced technologies—must be addressed to ensure both economic and environmental viability.

The PtL–FT process offers a promising pathway to generate SAF by converting renewable electricity into hydrogen, which is subsequently combined with CO₂ to form synthetic hydrocarbons. These hydrocarbons can then be refined into SAF, providing a low-carbon alternative to fossil-derived jet fuels. This pathway is particularly relevant for Australia, given its abundant solar and wind resources that can support large-scale green hydrogen production through electrolysis. Life Cycle Assessment (LCA) ensures that PtL SAF pathways align with global sustainability standards such as CORSIA and ASTM D7566 certification, while TEA evaluates economic feasibility, including the potential for SAF exports [84]. Figure 10 illustrates the boundary system of TEA and LCA in PtL SAF production, highlighting how the integration of these complementary approaches enables comprehensive system optimization.

Table 5. Boundary Condition Chart: TEA and LCA for PtL-FT SAF in Australia.

Category	TEA	LCA
Goal and Scope	Evaluate the economic feasibility of PtL FT SAF plant in Australia	Assess cradle-to-grave environmental impact of PtL-FT SAF produced in Australia
System Boundary	Gate-to-gate or cradle-to-gate (depending on scope)	Cradle-to-grave (electricity generation → CO2 capture → fuel)
Geographical Context	Australia—focused on renewable-rich regions (e.g., South Australia, Western Australia)	Australia—aligned with local grid mix, renewable energy availability, and national emission factors
Time Horizon	Plant lifetime, 20–30 years	100-year Global Warming Potential
Functional Unit	1 L or 1 MJ of SAF	1 MJ or 1 passenger-km (depending on study design)
Key Inputs	Renewable electricity Water CO2 (from DAC or point sources)	Renewable electricity CO2 capture source Catalysts and materials
Key Outputs	BAF (drop-in FT fuel) Oxygen (co-product) Economic indicators	BAF (with combustion emissions) Co-products (e.g., oxygen, waste heat) Emissions (CO2eq, NOX, etc.)
Energy Source	100% renewable (e.g., solar, wind, hybrid wind-PV)	100% renewable (e.g., solar, wind-hybrid-PV with storage)
CO2 Source	Direct Air Capture (DAC) Biogenic CO2	Not directly considered (except for embodied energy inputs)
Hydrogen Production	Water electrolysis (PEM or alkaline using renewable electricity)	Water electrolysis (renewable electricity only for baseline scenario)
FT Synthesis Conditions	Low-temperature FT (200–240 °C) with iron/cobalt catalyst; product upgrading	Low-temperature FT (200–240 °C) with iron/cobalt catalyst; product upgrading included
Capital Cost Assumptions	Not applicable	Energy-based or system expansion for co-products (e.g., oxygen)
End-of-Life	Not included	Fuel combustion included (CO2 counted as biogenic if captured via DAC/biogenic sources)
Environmental Impact Categories	Levelized Cost of Fuel Net Present Value (NPV) Payback Period	CO2 capture energy use Electricity carbon intensity Allocation method
Allocation Method	Not applicable	Energy-based or system expansion for co-products (e.g., oxygen)
Uncertainty/Sensitivity	Electricity price Electrolyzer efficiency/lifetime	Not applicable

further details the specific parameters and requirements considered within the TEA and LCA processes of this boundary system. Through detailed mass and energy balances, as well as sensitivity and uncertainty analyses, TEA and LCA together ensure that PtL SAF development is safe, profitable, and environmentally sound. This integration accelerates the aviation sector’s progress toward net-zero emissions.

5. Methodologies

This study looks at technoeconomic and life cycle evaluations of making FT-based e-fuels from hydrogen and carbon dioxide in the air using electrolysis and direct air capture (DAC). We carefully followed a review process that included making an exact search string, setting up selection criteria, and carefully extracting data.

5.1. Search String

A thorough search was done in four major databases-Google Scholar, Web of Science, Scopus, and PubMed to make sure the conclusions were strong and based on science. The goal of this search was to gather titles, abstracts, and keywords from journal articles and international conference proceedings that were published between January 2023 and June 2025. The carefully chosen set of keywords in the table guided the data collection. We chose these keywords carefully after looking at a lot of papers and journal articles that focused on the techno-economic and life cycle assessments of PtL-based FT-derived e-fuel production using hydrogen and carbon dioxide from the atmosphere.

Table 6. Literature search strings during January 2023–June 2025 *.

Date	Subject	Search Strings	Filter
January 2023–June 2025 (Web of Science, Scopus, Google Scholar, PubMed)	TEA	“TEA” OR “techno-economic analysis” OR “techno-economic assessment” OR “techno-economic viability” OR “techno-economic assessment” OR “economic viability” OR “economical assessment” OR “economic analysis” OR “technical” OR “technologies”.	Article title, Abstract, Keywords, Topic
	LCA	“LCA” OR “life cycle analysis” OR “life cycle assessment” OR “life cycle viability” OR “environmental viability” OR “environmental assessment” OR “environmental analysis” OR “environmental impact” OR “environmental fact” OR “Sustainability”.
	SAF	“SAF” OR “Synthetic fuel” OR “Sustainable aviation fuel” OR “E-Fuel” OR “Electro-Fuel” OR “Syn Fuel”.
	PtL	“PtL” OR “Power to liquid” OR “PtL based Fuel”.
	FT	“FT” OR “Fischer-Tropsch” OR “FT-SPK”.
	“English”		Limit to

* Search from Web of Science, Scopus, Google Scholar, and PubMed for information in article title, abstract, keywords, and topic.

delineates the search strings, where only used peer-reviewed journal articles, technical reports, and relevant conference papers that were published in academic journals to keep our review honest. Table 6 delineates the search strings, where only used peer-reviewed articles, technical reports, and relevant conference papers that were published in academic journals to keep our review honest.

The literature search and the presentation of findings were conducted in alignment with the directives laid out in Figure 11. In the initial search phase, 3779 scientific articles were identified from the database query. After eliminating 1035 duplicates and disqualifying records along with others for various reasons, were left with 2744 publications for closer examination. From these, 2684 were further excluded, and efforts were made to retrieve the remaining 60 reports. Also 6 are included from the backward search of recent publications. Of these, 16 could not be retrieved, leaving 50 for detailed eligibility assessment for screening of titles, abstracts, and keywords led to the inclusion of scientific articles. Subsequent in-depth full-text eligibility screening culminated in 50 articles being selected for comprehensive analysis.

The inclusion criteria for publications were as follows:

• Articles that specifically explored FT based e-fuel production for SAF utilizing green hydrogen and atmospheric CO₂.
• Studies offering a techno-economic analysis or a life cycle assessment of the PtL derived synthetic e-fuel production process.
• Works that were published in English during the years January 2023 to June 2025.

Conversely, exclusions were made based on the following:

• Articles that mainly focused on alternative aviation fuels without specifically addressing FT based e-fuels.
• Publications that were deficient in substantial data or lacked clarity in their methodology.

5.2. Data Analysis

Compared the synthesis data from the TEA and LCA to get a full picture of how the PtL-derived FT-based e-fuels production process works for SAF use. This meant organizing data based on how it was made. Putting the most cost-effective methods first. Finding the methods that are best for the environment. Looked at the chosen papers to find out about production technologies and how well they work, as well as their costs, break-even points, and return on investment calculations. Got LCA data that focused on getting raw materials, making things, emissions during use, and problems at the end of life. Used statistical software to combine the data from both analyses and get a single result. Based on the combined data, areas with too little research or results that didn’t agree were found. This gap analysis is very important for finding areas that need more research and for guiding future research.

TEA, a vital instrument in the development of e-fuels, evaluates the viability, economic viability, and environmental impact of several production routes. This section examines pertinent TEA evaluations pertaining to e-fuel development. It encompasses several techniques to produce green hydrogen gas from water, studied the use of DAC in conjunction with FT of CO₂ to produce e-fuels; and Rojas-Michaga and Michailos [84] combined DAC, offshore wind farms, and electrolysis to produce PtL e-SAF in the United Kingdom. By assessing e-fuels complete life cycle, from the extraction of raw materials to the disposal of them at the end of their useful life, LCA, is essential to comprehending the environmental effects of these fuels. The LCA research on e-fuels is methodically reviewed in this area, including information on their energy usage, greenhouse gas emissions, and general sustainability. This review highlights the potential environmental benefits and challenges associated with e-fuels by looking at different production pathways, such as electrolysis, DAC, and FT synthesis. This will help guide future research and policy decisions that aim to reduce the energy sector’s carbon footprint.

For our bibliographic collection, 50 articles from 35 countries and the results are illustrated through

Table 7. Summary of the findings of the previous research on the technoeconomic and life cycle analysis of E-fuel production.

Country, yr. and Refs.	Method	Parameter	Highlight	Result	Others	Limitation
KSA, 2025 [13]	SAF: FT, AtJ, PtL, HEFA, CHJ, DSHC	TEA: Efficiency, Cost LCA: Carbon emission	GHG emission by 26–93% compared to fossil jet fuel.	MJSP ranging from 0.39 to 11 USD/L.	FT SAF for long-term sustainability.	lack of production facilities
Malaysia, 2025 [117]	E-fuel: Electrolysis, CCS	TEA: Efficiency, Cost LCA: Carbon emission	Achieved 20% efficiency and 30–40% cost reductions.	70–90% carbon reduction vs. fossil fuel.	TEA requires costs below $3/kg.	Need for scalable e-fuel technologies.
Argentina, 2025 [118]	E-fuel: Electrolysis, CCU, FT, DAC	TEA: Capex, Opex and the profitability analysis.	Used 0.8 kgH2 and 3.1 kgCO2 /kg kerosene.	Achieved a kerosene yield of ~75 %.	NPV, IRR, Payback Period highlighted.	Sensitive to H2 costs and kerosene prices.
Turkey, 2025 [119]	E-fuel: Electrolysis, CCU, CCS	TEA: Technical feasibility	synthetic hydrocarbons and SNG are more compatible.	Green H2 presents the high decarbonization.	TEA is qualitative.	Lack of large-scale demonstration
USA, 2025 [120]	E-SAFs: CO2-based e-fuels.	TEA: Capex, Opex LCA: GWP	The potential of e-fuels to achieve net-zero emissions.	Capex, Opex for SAFs are higher than CJFs.	U.S. federal investments in SAF.	Uncertainty policy interventions
India, 2025 [121]	SAF: Renewable sources	LCA: GWP, technologies	Vital role in strengthening the circular bioeconomy.	SAF can decarbonizing the aviation sector.	sustainability assessment of SAF.	2nd and 3rd-gen biomass feedstocks
China, 2024 [36]	SAF: Technologies	TEA: economic viability. LCA: emissions, resource usage	Evaluates sustainable aviation fuel technologies and their readiness levels.	Significantly reduce emissions compared to conventional jet fuels	Recommendations for sustainable SAF industry development	Crucial for sustainable development
Turkey, 2024 [122]	SAF: technological advancements in fuel production	Evaluation: energy densities and footprints	Presents critical data on the aviation industry’s energy consumption, which reached 12.1 MJ/RTK in 2022.	With projections indicating a potential increase by 2.8 to 3.9 times by 2040	Aviation emissions could reach 2000 megatons by mid-century.	Economic incentives for SAF adoption require further exploration.
Poland, CZ, 2024 [39]	PtL: AtJ, FT	TEA: economic viability. LCA: carbon emissions.	SAFs can reduce carbon emissions by up to 80%.	SAF is currently more expensive than CJF.	Substantial energy required for AtJ fuel.	Energy density limitations of fuels.
Greece, DK, 2024 [43]	Alternatives fuels: production pathway	LCA: various alternative fuels	Various fuels assessed for environmental impact.	H2 is environmentally benign than other fuels.	quantifying carbon emissions, toxicity.	Require further exploration of TEA.
Australia, 2024 [123]	SAF: Three-step AtJet pathway, FT.	TEA: Economic analysis LCA: Carbon intensity	84.6% renewable power needed for comparable emissions reduction.	levelized cost of supply is 14%–25% lower than AtJ of the FT process.	Three-step AtJ pathway yields 1.6 times more SAF.	Higher capital cost for syngas fermentation.
Australia, 2024 [35]	E-Fuel: FT, RWGS, Electrolysis, DAC	TEA: Capex, Opex LCA: GWP	Economic viability relies on optimizing production.	E-fuels can reduce carbon emissions.	Suggests areas for future research	Identifies gaps in e-fuel production.
Switzerland2024 [124]	SJF: CO2 hydrogenation.	LCA: emission, resource usage, cost analysis	CO2 hydrogenation to methanol reduces GHG emissions by almost 50%.	Production cost is 7.86 EUR kgJF-1, 7 times higher than petroleum.	Electricity sources affect cost and emissions.	Challenges remain in terms of cost and energy demand.
India, 2024 [125]	SAF: PtL, FT.	LCA: environmental and costing feasibility.	SAF reduce environmental facts with renewable energy.	SAF are more costly than fossil kerosene.	Production process is energy intensive.	Need for more cost-effective SAF.
Australia, 2024 [126]	SAF: ML, Quantum mechanical	TEA: cost analysis. LCA: emissions.	Optimization of potential strained hydrocarbon	Exploration of strain energy in cycloalkanes.	screening of high-performance SAF.	Limited widespread H2 usage in aviation.
France, NL 2024 [127]	PtL: FT process (Matlab simulation)	TEA: energy efficiency	Global efficiency linked to H2 production efficiency.	Energetic efficiency reaches 48.06%.	Aspen Hysys for efficiency estimation.	No LCA
UK, 2024 [128]	FT-SPK: FT, CCS	LCA: well-to-wake and carbon footprint	FT-SPK with CCS generates negative carbon flux.	Certified blend reduces JF emissions by 37%.	FT-SPK limited to 50% blend with CJF.	UK cover 0.7% of JF demand.
Spain, 2024 [63]	SAF: All pathway based SAFs	LCA: CO2 emissions & commitment to climate change mitigation.	Aviation sector aims to reduce its impact on climate change.	Commercial aviation emitted 915 million tonnes of CO2 in 2019.	SAFs are being developed to reduce the carbon emission.	Does not provide a TEA and LCA
China, 2024 [129]	SAF: Electrolysis, captured CO2	Economic viability, and environmental benefits.	Analytical review of CO2 to jet fuel conversion methods.	High energy demands for carbon recycling.	H2 generation from renewable energy.	Limited exploration of TEA
USA, Brazil, 2024 [130]	SAF: All technologies.	TEA: technologies, Cost LCA: emission, policy	HEFA technology has highest readiness for commercial deployment.	SAF production operates at only 3.5% of potential capacity.	High production costs, 120% more than fossil fuels.	Only 38% of policies offer monetary incentives.
USA, 2024 [131]	PtL: FT e-kerosene, electrolysis, DAC	TEA: production costs, renewable energy expenses.	E-kerosene production cost expected to decrease significantly by 2050.	SAF production increased from 1.9 M to 15.8 M gallons in 6 yrs.	Cost reduction strategies for e-kerosene production.	High cost of kerosene produced with DAC.
Canada, 2024 [132]	SAF: PtL, FT, DAC	TEA: costs, resource and emissions	Negative emissions possible with cleaner electricity.	Resource and costs vary by province	Process highly resource intensive.	Requiring significant energy.
UK, 2023 [133]	SAF: 1sFT: noble Mn-Fe-K catalyst 2sFT: RWGS, FT	Enviro-economic: LCOP, GWP, environmental impacts	1sFT process has 70% and 30% lower externalities cost and GWP compared to 2sFT.	MSP of the fuel blend from the 1sFT is 20% lower than the 2sFT.	This emphasizes the benefits of adopting the 1sFT method.	Lack of TEA
UK, Bolivia, 2023 [115]	SAF: PtL, FT, CCU, DAC, Electrolysis.	TEA: CAPEX, OPEX LCA: GWP, Well-to-Wake system.	Carbon conversion of 88%, H2 conversion of 39.16%, PtL efficiency of 25.6%.	MJSP: 5.16 £/kg GWP: 21.43 gCO2eq/MJSAF.	WtWa water footprint is 0.480 l/MJSAF.	GWP below UK mandate of 50% emission reduction.
Norway, Sweden, 2023 [134]	SAF: PBtL, FT, Electrolysis by Aspen Plus® (V10)	TEA: process, cost, mass & energy balances LCA: sensitivity analysis	EU goal: 32% of total aviation fuel demand by SAF in 2040 can be met.	25 Mt a−1 fuel output achievable with direct renewable energy.	Only Norway and Sweden suitable as PBtL production.	Economic feasibility and environmental impact.
Italy, 2023 [135]	E-Fuel: Electrolysis by Aspen+	TEA: economic analysis, cost estimation.	PtL plant for producing 500 kg/h renewable methanol	LCoM calculated to be 960€/t (175€/MWh).	LCoM affected by electricity.	Not economically competitive.
UAE, Italy, 2023 [136]	Syn E-Fuel: DAC, Electrolysis, CCU, Hydrogenation.	TEA: TPC, LCCR, LCOM, CAPEX, OPEX	Cities with uneven solar energy distribution might need high H2 storage tank.	LCOM: 4.9–8.2 € kgCH4−1 with DAC, 3.1–3.9 € kgCH4−1.	LCOM > current methane price; need economic incentives	Electrolyzer is most expensive
KSA, 2023 [137]	Syn E-Fuel: CCU, CCS, Electrolysis.	TEA: CAPEX, OPEX, LCOe and MFSP	e-gasoline: MFSP of 3.24 USD/L; e-diesel: 2.89 USD/L for with solar.	LCOe from 379 to 564 USD/MWh	E-fuels can become a carbon-neutral option with CO2 taxation.	Need economic implications for decarbonizing road.
USA, 2023 [138]	E-Fuel: electrolysis, RWGS, FT, CCS, Hydrocracking.	TEA: Capex, Opex, energy efficiency. LCA: GHG, GREET.	MFSP: $0.95/L, $0.74/L, & $0.70/L of SAF mix for 100, 400, 1000 MWe energy plant.	GHG: 7 & −25 gCO2e/ MJ. 70% process energy efficiency.	99% carbon conversion by recycle CO2 & combustion.	WTW GHG emissions reduction of at least 92%.
Italy, 2023 [139]	SAF: E-Fuel, Syn-Kerosene, FT, DAC, Electrolysis.	TEA: Assumptions, sensitivity analysis, cost, process evaluations.	Indirect & direct processes produce 66.18 bbl/d & 38.46 bbl/d respectively.	Product cost varies: 460–1435 €/bbl & 752–2364 €/bbl.	Dependency on power energy and hydrogen prices.	Lack of LCA
Germany, 2023 [140]	SAF: LH2, LCH4, CCU, Electrolysis.	LCA: Holistic techno-economic assessment	LH2 costs: 157 €/MWh; LCH4: 217–228 €/MWh.	SAF costs: 279–302 €/MWh.	Limited CO2 reduction potential.	Focus on single fuel production costs.

and Figure 12C denoted by color intensity, which were mostly about countries in Europe (46% of the total publications) is as shown in Figure 12A,B. The Germany publishing the highest number of publications (7), UK (5), Italy (4), Turkey (3) [22], Netherland (2), Sweden (2), Norway (2), Switzerland (2), Iceland (1), Czech (1) [39], Portugal (1) and rest of them from others European countries [43,63]. This is followed Asia (9/50 publications), 15%, with 5 countries as follows: China (2/9), Saudi Arabia (2/9) [13], UAE (2/9), India (2/9) and Malaysia (1/9) and that of the North American continent is (8/50), including USA (6/8) and Canada (2/8). South America (6/50) contributed for 10% as follows: Chile (1/6), Argentina (2/6), Brazil (1/6), Bolivia (1/6) [115] and Ecuador (1/6). However, the contribution from Australia (4), 7% is comparatively small [35]. In addition, very few African (8%) countries have made contributions to the study [116]. Table 7 represents the Summary of the findings of the previous research on the technoeconomic and life cycle analysis of E-fuel production from 35 countries [117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140] in total contributed to the study of TEA and LCA of FT SAF. The scientific production of a country in one field is an index to evaluate the impact the country has on that specific academic field.

Table 7 represents the Summary of the findings of the previous research on the technoeconomic and life cycle analysis of E-fuel production in total contributed to the study of TEA and LCA of FT SAF.

5.3. Techno-Economic Viability and Life Cycle Impacts of SAF

In the study conducted in 2025 by SA Ali et al. [19]. an in-depth techno-economic and life cycle analysis was undertaken. It provides e-fuel production has achieved 20% efficiency improvements and 30–40% cost reductions, with TEA and LCA studies demonstrating 70–90% carbon reduction potential versus fossil fuels, while pilot projects confirm technical feasibility across sectors, though commercial viability requires costs below $3/kg. In the same year, an Argentain e-fuel plant achieves a kerosene yield of ~75%, supported by effective thermal integration and auxiliary services [116]. The plant uses 0.8 kgH₂ and 3.1 kgCO₂ per kg kerosene, utilizing H₂ from wind energy and captured CO₂ from a gas turbine [117]. Since FY 2017, a variety of U.S. federal government initiatives have funded R&D efforts related to SAF and begun to address CAPEX, OPEX and production cost premiums [118,119].

Wang, M et al. [36] provides a detailed life cycle emissions assessment, which is crucial for determining the environmental impact of SAF. The LCA discusses the potential of SAF to significantly reduce emissions compared to conventional jet fuels, highlighting its role in achieving sustainability goals [35]. The paper argues for the economic viability of SAF through a techno-economic analysis. This analysis examines the costs and economic conditions surrounding SAF production, which is essential for stakeholders to make informed decisions about investments and development in this sector. With an emphasis on carbon conversion, hydrogen conversion, and power-to-liquids efficiency, Rojas-Michaga, Michailos [114] carried out the study combining techno-economic and life cycle evaluation. A refinery plant, an offshore wind farm, an alkaline electrolyser, and a DAC unit were all incorporated into the system. Power-to-liquid (PtL) fuels were made using these. The efficiency of power-to-liquids was 25.6%, the carbon conversion was 88%, and the hydrogen conversion was 39.16%. It was determined that the Margin Jet Fuel Price (MJSP) was 5.16 £/kg [141].

Caner İlhan conducted the research combined both techno-economic and life cycle assessment [121] with a focus on the aviation industry’s energy consumption, which reached 12.1 MJ/RTK in 2022, with projections indicating a potential increase by 2.8 to 3.9 times by 2040 [142]. This information underscores the need for alternative energy sources to meet future demands [90]. The study forecasts that without a strategic shift, aviation emissions could reach 2000 megatons by mid-century. This projection emphasizes the potential environmental crisis and the necessity for immediate action within the industry. A life-cycle assessment was carried out by Ravi, Mazumder [137] emphasizing life cycle emissions associated with SAF, highlighting that these fuels can reduce carbon dioxide emissions by up to 80% compared to traditional fossil fuels. This positions SAF as a nearly carbon-neutral option when considering the full lifecycle of production and use. Evanthia A. Nanaki in Denmark also conducts a comprehensive LCA to evaluate the environmental impacts of various alternative energy fuels (AEFs) compared to conventional jet fuel. This includes quantifying emissions in terms of carbon dioxide equivalents, acidification, eutrophication, eco-toxicity, human toxicity, and carcinogens [92].

Alexander Barke in 2022, focused on the economic feasibility and environmental impact [143], The study highlights that while SAFs can reduce greenhouse gas emissions during flight operations, their production is often energy-intensive and can have negative environmental effects. The paper emphasizes the importance of using a renewable energy mix in the production of these fuels to achieve significant environmental benefits. The research reveals that, from an economic perspective, fossil kerosene remains more competitive than SAFs due to higher production costs associated with alternative fuels. The paper discusses the need for political measures, such as subsidies or tax incentives, to enhance the market penetration of SAFs [142].

Research encompassed a thorough techno-economic evaluation of the SAF production pathways in Australia. It highlights that, despite higher capital costs associated with the three-step Alcohol-to-Jet pathway, the levelized cost of supply is 14–25% lower than that of the FT process [144]. This finding is essential for stakeholders in the aviation industry to understand the cost-effectiveness of different SAF production methods. The research offers valuable insights into the carbon intensity of SAF production. It establishes that achieving emissions comparable to conventional jet fuel requires at least 84.6% of the power used in SAF production to come from renewable sources [123]. This contribution emphasizes the importance of renewable energy integration in reducing the carbon footprint of aviation fuels.

A. Bernalte García et al. [132] propose a flexible, technology-neutral heuristic to approximate the minimum selling price (MSP) of SAF. This approach allows for easier generalization and application across various emerging technologies, addressing the limitations of current techno-economic methods that can be extensive and complex. The paper demonstrates the use of the heuristic to evaluate strategies aimed at minimizing the cost of CO₂ abatement for different SAF processes. This evaluation is crucial for guiding the development of economically viable and environmentally friendly production pathways.

Furthermore, in 2024, Australia underwent a comprehensive technical and economic analysis of the production of new SAFs [35]. This assessment is crucial for evaluating the feasibility and economic viability of implementing these fuels on a larger scale. On the other hand, in 2024, Switzerland and Sweden conduct a LCA of synthetic jet fuel production reveals significant reductions in GHG emissions and cost compared to conventional jet fuel. However, challenges remain in terms of cost and energy demand [125].

Colelli and Segneri conducted a thorough technical and financial study on the production of synthetic kerosene from green H₂ and DAC CO₂ in Italy in 2023 [138]. They used a combination of FT synthesis, CO₂ capture, RWGS, and hydrogen produced by water electrolysis. They carried out process assessments and sensitivity analysis. The production rates from the direct and indirect processes were 38.46 and 66.18 barrels per day, respectively. Furthermore, the cost of the product varied greatly, ranging from 752–2364 €/bbl for the direct process to 460–1435 €/bbl for the indirect method. The analysis identified a significant reliance on the price of hydrogen and electricity generation.

Sweden also conducted a techno-economic analysis in 2024 and 2021 that was anticipated to cover the years 2020–2050 [133]. To produce RJF from lignocellulosic biomass and collected CO₂, they employed Fischer-Tropsch (FT), HTL, and PTL (with a Python 3.9 MILP model) techniques [101]. According to the analysis, the blending ratio will lead to a rise in overall RJF output. They predict that RJF output will be between 3.85 and 16.87 TJ by 2030–2050 [35]. Additionally, the cost of producing HTL and PTL jet fuel varies; prices are expected to range from 24.2–25.4 SEK/L for HTL and 16.7–22.0 SEK/L for PTL. Importantly, by-product revenue may enable HTL and PTL approaches to provide competitive prices.

Gençer Zimmermann [136] focuses on TEA in relation to market potential and cost. Notably, the cost of products made per gigajoule (GJ) for OME3-5 e-fuels is substantially greater than that of traditional diesel fuel found at German petrol stations. Based on a reduced heating value, the study shows that e-fuel can effectively retain less than 38.4% of power. Rather than the cost of OME conversion, the most significant economic constraints found are related to energy usage and the price of electrolyzer stacks. The OME3-5 anhydrous route would not be economically viable in the current environment, even if the cost of energy or electrolyzers were significantly reduced. To increase the future economic feasibility of OME3-5 e-fuels, this highlights the necessity of major developments in reaction processes and system enhancements.

Cames and Chaudry [141] draw attention to a serious issue with CO₂ storage brought on by IPCC predictions. It highlights the possibility of a scarcity of appropriate, affordable, and easily accessible CO₂ storage locations due to the considerable amount of CO₂ that has to be stored. The research highlights the cost difference between e-fuels and direct air capture and carbon storage (DACCS) solutions in this context, showing that by 2050, the difference will range from 1.0% to 2.5% of the ticket price. In addition to a techno-economic analysis, a thorough life cycle assessment (LCA) was conducted by [104]. When reliant on offshore wind power, the LCA found a global warming potential (GWP) of 21.43 gCO₂eq/MJ synthetic aviation fuel (SAF). Compared to fossil jet fuel, this GWP is far lower than the UK’s target, which calls for a 50% decrease in emissions. Furthermore, the water-to-water adjusted (WtWa) water footprint was calculated to be 0.480 l/MJSAF, illustrating the process’s wider environmental effect.

Pipitone and Zoppi [135] assessed the process’s environmental viability, paying special attention to its carbon impact. A substantial reduction in the environmental effect was demonstrated by the advanced scenario, which had a carbon footprint of 12 g CO₂/MJSAF, 54% lower than that of conventional approaches. Habermeyer and Papantoni [137] conducted life cycle analysis (LCA) research to evaluate the approaches’ effects on the environment. According to the findings, it is possible to produce 25 Mt a−1 of fuel utilizing direct renewable power sources and 33% forest waste. This might help the EU reach its target of 32% of SAF’s total aviation fuel usage by 2040.

Zang and Sun [139] carried out LCA research that concentrated on the WTW GHG emissions of FT fuels that come from electrolytic H₂ channels and CO₂ sources. The results, which considered several process designs and system limits, demonstrated that when combined with corn ethanol production, FT fuels had WTW GHG emissions that are 57–65% lower. Moreover, FT fuel had 58% energy efficiency and fixed 45% of the carbon in CO₂. When compared to petroleum fuels, the WTW GHG emissions were drastically reduced by 90–108% using sources such as nuclear, solar, and wind generation. Another research that looked at PtL’s potential and effects on the environment revealed that PtL generated from wind energy might lessen environmental impact by as much as 42% [138].

Break-even points, which are frequently represented by metrics like MFSP, offer vital information on the viability of producing e-fuel in various settings. The importance of the energy source in influencing production costs was shown by the fact that MFSP values in the USA varied according to nuclear power plant capabilities [139]. Comparably, the LCOM in the UAE and Benevento and the LCOe in KSA offer essential standards for evaluating the financial effects of e-fuel manufacturing. Some studies point to the need for further financial incentives or technological advancements, while others present favorable return-on-investment scenarios, such as the e-fuel production costs seen in Turkey in 2022 [140]. For example, the LCOM values were higher than the current methane market price. This discrepancy highlights how crucial it is to put TEA in context and acknowledge the flexibility of its consequences for the market, technology, and policy [141].

Given China’s plentiful agricultural biomass supplies in 2024, the techno-economic analysis shows that manufacturing SAF from crops using the gasification–FT process is economically feasible in China [128]. The study considers the expenses related to the generation of hydrogen through electrolysis, CO₂ through direct air capture (DAC), and synthetic natural gas (SNG) through condensation and TEG absorption. According to the study, US tax incentives for the generation of low-carbon hydrogen can drastically lower SNG prices. With a 45 V tax credit and an energy price of 0.03 USD/kWh for water electrolysis, the cost of SNG is comparable to that of fossil NG. By increasing SNG’s economic viability, the 45 V tax credit makes it a viable substitute for fossil fuel NG [128].

The MFSP in Saudi Arabia is USD 2.89/L for e-diesel and USD 3.24/L for e-gasoline. According to an Italian economic analysis, the LCoM is 960 EUR/t, while German research predicts that by 2050, the cost of producing e-fuels will have decreased to 1.8–3.1 EUR/kg [136]. According to UK research, the carbon conversion efficiency is 88% and the power-to-liquids efficiency is 25.6% [123]. Another study conducted in the USA shows that FT has a 70% process energy efficiency. According to Chinese research, ETJ had the lowest energy and GHG emissions, measuring 370.05 KJ/MJ and 31.66 gCO₂eq/MJ, respectively. According to research conducted in the USA, e-fuels can cut WTW GHG emissions by 57–65% [114]. Additional research conducted in Norway emphasizes how important the environmental framework is to the adoption of CCU and e-fuels [136].

A study in India, employs LCA methods to evaluate the ecological implications of four types of alternative fuels compared to traditional fossil kerosene. This comprehensive analysis provides insights into the environmental benefits and drawbacks of using SAFs, emphasizing the need for a renewable electricity mix to achieve significant reductions in environmental impacts [124]. However, another study in Australia, highlights the necessity for a TEA of the production of new SAFs. This assessment is crucial for evaluating the feasibility and economic viability of implementing these fuels on a larger scale [117]. SAFs are increasingly becoming a focus of research and development as the aviation industry seeks to reduce its carbon footprint. A critical aspect of assessing the feasibility and viability of SAFs is conducting a techno-economic analysis to evaluate their cost of production and economic competitiveness compared to conventional jet fuels. In this section, we delve into the techno-economic analysis of synthetic E-fuels, which are produced from CO₂ and H₂, for use as sustainable aviation fuel. Depending on the exact product of interest, CCU may be referred to in literature or various databases as “electrofuels”, “PtL”, “CCU”, “Power-to-Aviation”, and so on. Gathering these names with other keywords, such as “techno-economic analysis”, “environmental analysis” or LCA, different search engines provide a range of publications and studies, the number of which grows year after year. The current level of PtL, TEA and LCA research revolves around 3 major applications:

(i)

storing of intermittent electricity generation (as wind or PV) [105,106],

(ii)

production of 27 transportation fuels [38,39,59,97,107,108,109,110,111,112], and

(iii)

production of chemical substances [95,97,111].

The PtL pathway for producing FT-derived fuels is a relatively novel alternative method. There is no any single drop of SAF produced in Australia from PtL so far. There is an extensive bibliography on methane [113,114,115] and hydrogen synthesis [116,117,118,119,120,121,122]. Similarly, there have been numerous studies on the environmental performance of this manufacturing process, with most of them concentrating on estimating the GWP [123,124,125]. Some study on technical and experimental [126] performances of the PtL process or bottleneck areas of the process is currently being developed. König et al. [110] discovered that the PtL process had a carbon conversion rate of 73.7% and an efficiency of 43.3% using process modelling. High PtX (Power to any product) costs relate to high capital expenses and H₂ production costs (mostly impacted by energy and electrolyser capital costs). Tremel et al. [108] examined several fuel/chemical synthesis methods in terms of technology, economics, and acceptance; FT has excellent public acceptance due to its product’s likeness to traditional fossil fuels. Furthermore, they discovered that the high cost of H₂ generated by water electrolysis is the primary cause for the high cost of PTX fuels and chemicals. There has been minimal study that explicitly examines the manufacturing of SAF using a PtL technique that is currently accessible. Economic evaluations are often performed to determine the cost and economic viability of such a process, taking into consideration the feedstock, energy, and capital investment requirements. Three separate papers evaluated the economic and environmental performance of PtL-derived SAF. By analysing short- and long-term scenarios, these reports determined whether this method was economically viable. Furthermore, the estimated minimum jet fuel selling price of the SAF is much higher when compared to the gate price of conventional jet fuel.

Critical Analysis

There appears to be a heterogeneity of metrics employed across various studies for the assessment of both techno-economic and environmental dimensions of e-fuels production. Illustrative examples follow. The studies encompass a range of metrics, including “minimum fuel selling price (MFSP)” and “levelised cost of Fuel (LCoF)” for evaluating economic viability, thereby complicating direct comparisons. This divergence underscores the necessity for standardised metrics to establish clearer benchmarks for comparative analyses [136,145]. The research predominantly concentrates on conventional feedstocks such as CO₂, H₂, and biomass. Nonetheless, the origin of these feedstocks (for instance, direct air capture versus point-source capture for CO₂, or various types of biomass) may yield substantial disparities in both economic and environmental results. Investigations that specifically focus on a direct comparison of feedstock sources are relatively scarce [135,138]. Several studies accentuate the advantages of integrated systems, such as the amalgamation of FT synthesis with corn ethanol production or the incorporation of power-to-methanol with MSW gasification. However, the comparative benefits of these integrated systems in relation to standalone processes necessitate more exhaustive research [115,146]. The studies originate from diverse geographical contexts [147,148], each characterized by distinct energy infrastructures, regulatory frameworks, and natural resource endowments. Although some studies offer specific insights pertinent to their respective regions, a holistic comparative analysis regarding the influence of geographical factors on the economic and environmental ramifications of e-fuel production is conspicuously absent. Certain studies [139,149] allude to the significance of technological advancements; however, comprehensive examinations of how emergent technologies (such as advancements in catalysts, electrolysers, or carbon capture methodologies) may transform existing paradigms are relatively limited. While numerous studies [150,151] utilize LCA and primarily concentrate on greenhouse gas emissions, other environmental ramifications, including water consumption, land utilization, or effects on biodiversity, are less frequently addressed. This deficiency in comprehensive environmental assessments may overlook some indirect adverse impacts associated with specific e-fuel production methodologies. The research conducted by Romo Martínez [152] emphasizes the importance of carbon CCU and H₂ based e-fuels in consideration of societal acceptance, regulatory factors, and safety protocols. Nevertheless, these socio-political dimensions are infrequently examined in other investigations, indicating a potential lacuna in the research landscape. Regarding economic viability, some studies [151,152,153,154,155] draw attention to the elevated costs linked to the uneven distribution of solar energy, whereas others, such as the research conducted in the UK, suggest comparatively lower costs and favorable outcomes. These contradictory findings indicate that variables such as local conditions, technology selections, and feedstock sources can significantly affect results, thereby underscoring the requirement for more standardized assumptions and scenarios.

5.4. Cost of Production: Current Status and Future Projections

The cost of production is a key factor in determining the feasibility of synthetic E-fuels as a sustainable aviation fuel source. Currently, the cost of producing synthetic E-fuels is higher than that of conventional jet fuels, primarily due to the high cost of hydrogen production and the limited scale of synthetic E-fuel production facilities. Electrochemical reduction and Fischer-Tropsch synthesis are among the primary pro-duction pathways, and both require significant energy inputs. The cost of renewable energy for H₂ production is a major component of the overall cost, and advancements in low-cost, green H₂ production methods are crucial to reducing the cost of E-fuel production.

The cost distribution for the four main technological pathways, FT, AtJ, HEFA, and E-Jet including feedstock contributions, CAPEX, and OPEX is shown in Figure 13 [153]. The cost structure of the HEFA route is comparatively balanced, with OPEX making up 8–10% and CAPEX accounting for 22–40%, including infrastructure associated to hydrogen. The reliance on lipid-based resources, such as waste oils, is revealed by the fact that feedstocks account for the biggest cost share (51–69%). With CAPEX ranging from 54 to 81% and OPEX comprising 12 to 21% and feedstock prices varying from 0 to 32%, the FT method is notably capital-intensive.

However, it offers considerable flexibility because it may make use of inexpensive or subsidized biomass. AtJ needs to spend heavily in infrastructure for the processing of alcohol, which results in 45–75% CAPEX contributions, comparatively low OPEX (2–14%), and moderate feedstock expenses (20–44%), depending on the kind of alcohol. On the other hand, because hydrogen-related expenses fall under feedstock, which accounts for 70–85% of the cost profile because of the energy-intensive processes required in CO₂ collection and green hydrogen synthesis, E-Jet fuels have the lowest CAPEX range (5–20%); OPEX varies from 5 to 15%.

Overall, FT and AtJ are hampered by high capital costs, whereas feedstock costs predominate in HEFA and E-Jet paths. In order to achieve cost-effective deployment and scaling, these findings emphasize the significance of tailored financial and regulatory interventions that consider the unique economic features of each SAF route. In addition to renewable H₂, the cost of CO₂ capture and storage technologies also plays a significant role in the cost of production. As carbon capture and utilization technologies advance and become more widespread, they have the potential to lower the cost of CO₂ feedstock.

5.5. Economic Viability and Challenges

Evaluating the economic viability of synthetic E-fuels involves comparing their cost to that of conventional jet fuels derived from crude oil. Because the aviation industry has very low profit margins, it is very important to keep an eye on fuel costs. Even though the cost of making synthetic E-fuels is high right now, they are expected to become economically viable through better efficiency and economies of scale. Also, as the aviation industry is under pressure to cut carbon emissions, it may be more willing to invest in SAF. The price of crude oil, government incentives, carbon pricing, and the need for SAF all affect how economically viable synthetic E-fuels are. The recovery after COVID-19 gives governments and businesses a chance to invest in the development of SAF, which will make the economy more competitive. Tax reducing, research grants, and low-interest loans for the growth and infrastructure of synthetic E-fuels are all possible ways to help. Carbon pricing mechanisms can make traditional jet fuels more expensive, which can make people more likely to use SAF.

LCA looks at how making synthetic natural gas (SNG) from low-carbon hydrogen and carbon dioxide capture affects the environment. Studies show that SNG can cut greenhouse gas emissions over the course of its life by 52 to 88 percent compared to fossil natural gas, depending on the energy sources used. Using renewable energy to make hydrogen and store CO₂ connects SNG to the United States’ goals for sustainable energy.

Combining life cycle assessments with techno-economic evaluations gives us a lot of information about the sustainability of e-fuels. This method is necessary to make sure that long-term ecological results and initial financial evaluations are in agreement. The RWGS reaction and high-temperature electrolysis are two major breakthroughs that improve carbon conversion efficiency, but their economic viability depends on the size of the operation and future technological advances. TEA of synthetic E-fuels show that there are still problems with the cost of making them and their financial viability. Even so, advances in technology and policies that support them make synthetic E-fuels very promising for the aviation industry’s long-term health. For an economy to work, industry, government, and technology need to work together.

In these studies, the TEA of synthetic E-fuels for SAF highlights the current challenges in terms of production costs and economic competitiveness. But better technology and policies that support it suggest that synthetic E-fuels could be a big part of making flying better for the environment. Businesses, governments, and new technologies all need to work together to keep the economy strong. There are big scientific and economic problems with making and using SAFs, so the aviation industry can’t grow. The many types of feedstocks are a big technological problem because they have different properties and aren’t always available. This influences how well fuel works and how well it is made. It is harder to stabilize supplies when other businesses are competing for feedstocks, and conversion methods make things even more complicated. Two big areas of study are making catalysts work better and figuring out how to use renewable energy in PtL processes.

The manufacture and marketing of Sustainable Aviation Fuels (SAFs) confront substantial technological and economic obstacles that limit their scalability and acceptance in global aviation. One of the most significant technical challenges is the variety of feedstock. SAFs can be created from a variety of sources, including biomass, municipal solid waste, industrial pollutants, and agricultural leftovers. However, the uneven quality, availability, and seasonality of these feedstocks have an impact on fuel performance, production efficiency, and scalability. Competition for these feedstocks from other industries challenges their secure and long-term supply. Conversion methods such as FT synthesis, hydrotreatment, and alcohol-to-jet procedures also provide technological challenges. These processes frequently need costly catalysts, run under energy-intensive conditions, and are sensitive to input contaminants. Developing more robust, cost-effective, and selective catalysts is an important research topic. Including renewable energy sources such as solar or wind for green hydrogen generation is critical for Power-to-Liquid (PtL) routes, but present systems remain inefficient and expensive to operate.

Commercialization and Collaborative Efforts of SAF

The commercialization of SAFs is experiencing significant advancement as a pivotal strategy for the decarbonization of the aviation sector, albeit considerable economic and infrastructural obstacles remain. Present production levels constitute approximately 3.5% of the feasible capacity, with expenditures averaging over 120% higher than those of conventional jet fuel [154]. Ambitious policy frameworks, exemplified by the U.S. SAF Grand Challenge which aims for an annual output of 3 billion gallons by 2030 and 35 billion gallons by 2050, emphasize the magnitude of transformation necessary, necessitating a 130 fold escalation in production relative to existing baselines [155]. Certification via ASTM D7566, encompassing HEFA at TRL 9, has established a comprehensive regulatory framework for implementation, while advanced methods such as ATJ and PtL are increasingly demonstrating techno-economic viability [123,156]. Investment dynamics reflect growing confidence, with hydrothermal liquefaction integrated scenarios demonstrating life-cycle greenhouse gas reductions of 73–82% versus fossil jet fuel, positioning waste cooking oil and tallow feedstocks as commercially viable pathways with 2.8–5.8 times greater emissions reductions [157,158]. The commitments from airlines, bolstered by ICAO targets and alignment with UNSDG 13, reflect a growing confidence in SAF [99,104]. With lifecycle assessments indicating potential reductions in GHG emissions of up to 80% and diversification of feedstock contributing to supply resilience [101,102,103], the commercialization of SAF, although constrained by cost, is progressively being recognized as an essential component of the aviation sector’s sustainable transition. Collaborative efforts between industry and academia are propelling advancements in catalyst design, feedstock optimization, and process efficiency, while policy incentives spanning from carbon pricing to renewable fuel credits are attracting private investment and venture capital [96,97,98].

Making SAF is still too expensive compared to regular jet fuel from an economic point of view because of high capital and operational costs. The difference in costs is a big problem for airlines, but government incentives are starting to close the gap in some places. A lot of money needs to be spent on infrastructure to make the SAF market strong. But changes in fossil fuel prices could make the market less competitive. For SAF to be possible in the long run, it needs to be able to compete with fossil fuels on price and get ongoing support from regulators. The only way to solve the problems that are both technological and economic is for the government, businesses, and academics to work together. Need new conversion technologies, a wider range of feedstocks, better energy efficiency, and laws that make it easier to do all of this for SAFs to be a viable option for lowering carbon emissions in aviation.

6. Conclusions and Outlook

The rise in SAFs has been noted worldwide and SAFs are supported by major states and international organisations due to this aviation fuel regulation reform. IATA wants SAFs to make up 10% of aviation fuel by 2030 [21]. The US and EU offer incentives, requirements, and subsidies for SAF production and UN International Civil Aviation Organization (ICAO) is striving to simplify SAF use and define worldwide environmental criteria [23]. All these efforts illustrate that everyone thinks SAFs make flying more sustainable. Pressure is mounting on the aviation industry to reduce its carbon footprint and fulfill international climate goals like the Paris Accord [24]. SAF might reduce named emissions over Palladium compared to fossil-based Jet A fuel. To reduce carbon emissions, the aviation industry must make this decision. Tallow, city waste, and other bio-based products are used to make SAF. Before SAF is extensively deployed, many technological, financial, and regulatory obstacles must be handled. Based on comprehensive literature reviews, several viable production pathways offer promising routes for large-scale SAF deployment.

HEFA represents the most commercially mature pathway, utilizing waste cooking oils, used vegetable oils, and dedicated oil crops through established hydroprocessing technology, though scalability is constrained by sustainable feedstock availability [153]. FT synthesis offers exceptional feedstock flexibility, converting biomass, municipal wastes, or CO₂ through gasification and catalytic conversion, with PtL variants showing particular promise when coupled with renewable electricity and electrolytic hydrogen production [159]. ATJ processes present an innovative approach, particularly CO₂-derived variants that can achieve 1.6 times higher SAF yields and 14–25% lower production costs compared to conventional FT routes by integrating carbon capture with renewable energy systems [123,160]. Advanced catalytic processes are revolutionizing production efficiency through atomic-scale catalyst design and improved selectivity in syngas conversion and hydroprocessing steps [161,162]. Emerging technologies such as waste tire and plastic pyrolysis-gasification demonstrate competitive economics while addressing waste management challenges, and photocatalytic reforming offers novel pathways for simultaneous hydrogen production and waste valorization [163,164].

For Australia’s unique context, the integration of abundant renewable energy resources with PtL pathways, combined with the country’s strong R&D capabilities in advanced catalysis and waste-to-fuel technologies, positions the nation to develop a competitive and sustainable SAF industry that can meet both domestic aviation needs and export opportunities while contributing to global decarbonization targets. This review examined the environmental impact and technology and economic performance of SAFs throughout their life cycle and their viability in Australian aviation has been the focus.

SAFs, manufactured from biomass and synthetic e-fuels, minimize aviation’s fossil fuel use and greenhouse gas emissions. They reduce particulate pollution, clean the air, and make energy safer. Australia is far from other countries and has many resources, making this crucial. However, many major difficulties remain. Not much biomass can be used to manufacture SAFs, and changing it is expensive. The SAF also competes with food and power. Synthetic e-fuels fit with aviation infrastructure and long-term carbon emission reduction targets instead of, they are energy-intensive and expensive to produce. Government regulations, market incentives, and technology advancements affect the economy in both circumstances. The market struggles to accept these items due to international regulations and the expensive cost of certification methods like ASTM D7566. Despite these challenges, Australian SAFs are doing well. The country has abundant renewable energy, strong R&D, and growing government support for SAF. All these factors make it ideal for a competitive SAF sector. Better power-to-liquid, carbon capture, electrolysis, and catalytic synthesis should cut production costs, especially when scaled up. To balance cost, scalability, and sustainability, research and policymaking should use LCA and TEA frameworks. Government, business, academia, and foreign partners must collaborate to eliminate aviation pollution. Aligning policies, building infrastructure, and changing rules can help SAF spread faster. SAFs, especially synthetic e-fuels, could help the Australian and global aviation sector transition to a low-carbon future with the appropriate backing and fresh ideas.

This study brings together recent SAF research and provides crucial information regarding emerging technologies including carbon capture and PtL synthesis. These innovations could make aviation fuels greener and help the globe become more sustainable. The evaluation emphasizes the need for academia, industry, and the government to collaborate to remove barriers and accelerate innovation. It provides a roadmap for SAF deployment, notably in Australia, where long-distance travel, renewable energy, and strong climate policies coexist.