Myth-busting Sustainable Aviation & Shipping: Separating Hype from Reality

In 2024, sustainable aviation fuel (SAF) production doubled to 1 million tonnes, yet this represents less than 0.5% of global jet fuel consumption. Meanwhile, the maritime shipping industry—responsible for nearly 3% of global greenhouse gas emissions—faces a $2.4 trillion investment gap to achieve net-zero targets. These stark numbers reveal a fundamental truth: decarbonizing transportation's hardest-to-abate sectors requires moving beyond marketing narratives to understand what actually works.

Why It Matters

Aviation and maritime shipping together account for approximately 5% of global CO₂ emissions, with projections suggesting this share could triple by 2050 without intervention (International Energy Agency, 2024). The urgency intensifies when considering that both sectors lack viable battery-electric alternatives due to energy density constraints—jet fuel contains roughly 43 times more energy per kilogram than lithium-ion batteries.

For Asia-Pacific specifically, this challenge is existential. The region handles over 60% of global container traffic through ports like Singapore, Shanghai, and Busan. Singapore alone processes 37 million TEUs (twenty-foot equivalent units) annually, making its decarbonization pathway a bellwether for the entire industry. Meanwhile, Asia-Pacific aviation markets are projected to grow 4.5% annually through 2040, faster than any other region (Boeing Commercial Market Outlook, 2024).

The metrics that matter extend beyond carbon intensity. Life cycle assessments (LCA) must account for upstream emissions from feedstock production, water consumption in biofuel processing, and the opportunity costs of biomaterials diverted from other uses. Without rigorous measurement frameworks, billion-dollar investments risk funding solutions that merely shift environmental burdens rather than eliminating them.

Key Concepts

Sustainable Aviation Fuel (SAF) Pathways

SAF encompasses multiple production technologies certified under ASTM International standards. As of 2025, seven pathways have received approval:

Technology	Feedstock	Max Blend	2024 Market Share
HEFA-SPK (Hydroprocessed Esters and Fatty Acids)	Used cooking oil, tallow	50%	82-99%
FT-SPK (Fischer-Tropsch)	Municipal solid waste, biomass	50%	<5%
ATJ-SPK (Alcohol-to-Jet)	Ethanol, isobutanol	50%	~3%
SIP (Synthesized Iso-Paraffins)	Sugars	10%	<1%
Power-to-Liquid (PtL)	CO₂ + green hydrogen	50%	<1%

The dominance of HEFA-SPK creates a critical bottleneck: global used cooking oil supply can theoretically produce only 5-7 million tonnes of SAF annually, far below the 350+ million tonnes of jet fuel consumed each year.

Maritime Decarbonization Options

Shipping faces even more complex tradeoffs. The International Maritime Organization's (IMO) revised 2023 strategy targets net-zero emissions by "around 2050," with interim targets of 20% reduction by 2030 and 70% by 2040 (from 2008 baseline). Key alternatives include:

Green ammonia: Zero-carbon at point of use, but requires $8-12/kg production costs to compete (current green ammonia: ~$6/kg, conventional: $0.30/kg)
Green methanol: 100+ vessels ordered with methanol-capable engines, led by Maersk
LNG: 50% lower CO₂ than heavy fuel oil, but methane slip undermines benefits
Wind-assist technologies: Proven 10-30% fuel savings on bulk carriers

Life Cycle Assessment Frameworks

True decarbonization requires full LCA accounting. The EU's ReFuelEU Aviation regulation mandates a 70% lifecycle emissions reduction for SAF relative to fossil jet fuel. This includes:

Well-to-wake analysis: From feedstock cultivation through combustion
Indirect land use change (ILUC): Emissions from displacing food crops
Water intensity: Some biofuel pathways consume 2,000+ liters per liter of fuel
Energy return on investment (EROI): Net energy delivered versus energy consumed in production

What's Working

Regulatory Mandates Creating Demand Certainty

The EU's ReFuelEU Aviation mandate, effective January 2025, requires a 2% SAF blend at all EU airports, rising to 6% by 2030 and 70% by 2050. This regulatory certainty has unlocked $50+ billion in announced SAF production investments globally.

Singapore's Maritime Decarbonization Pilot demonstrates Asia-Pacific leadership. The Maritime and Port Authority of Singapore (MPA) launched a $300 million Maritime Decarbonisation Centre in 2024, partnering with DNV, A.P. Moller-Maersk, and BHP to test biofuel blends, shore power infrastructure, and digital optimization tools. Early results show 15-20% fuel consumption reductions through AI-optimized routing and just-in-time arrival systems.

Industry Offtake Agreements

Long-term purchase agreements are de-risking project finance. Air New Zealand signed a 30 million liter SAF supply agreement with Neste in 2024, while Air Canada committed to 77.6 million liters over multiple years. TotalEnergies and Lufthansa announced plans for up to 2 million tonnes annually by 2030.

Technology Breakthroughs Expanding Feedstock

LanzaJet opened the world's first commercial ethanol-to-jet facility in 2024 in Soperton, Georgia, with 10 million gallons annual capacity. This alcohol-to-jet pathway can utilize agricultural residues and waste ethanol, bypassing the used cooking oil constraint. Montana Renewables commenced operations at the largest U.S. SAF facility (180,000 barrels per day capacity), converting soybean oil and distillers corn oil.

What's Not Working

Cost Premium Persistence

SAF remains 2-5x more expensive than conventional jet fuel, with prices ranging from $4-8 per gallon versus $2-3 for Jet-A. Despite tax credits—the U.S. Inflation Reduction Act offers $1.25-1.75 per gallon—the premium creates resistance from cost-sensitive airlines operating on 1-3% margins.

Infrastructure Gaps

Only ~1% of required SAF infrastructure is operational globally. Airports lack dedicated storage, blending, and distribution systems. Singapore's Changi Airport invested $25 million in SAF-capable hydrant systems, but most Asia-Pacific airports have no such plans.

Greenwashing Through Accounting Loopholes

"Book and claim" systems allow airlines to purchase SAF certificates without physically using the fuel, raising additionality concerns. While this mechanism enables SAF deployment at production-site airports, critics argue it delays infrastructure investment at high-traffic hubs.

Maritime Pilot Fragmentation

Despite 100+ green corridor initiatives announced globally, few have advanced beyond memoranda of understanding. The Singapore-Rotterdam green corridor, launched in 2022, has yet to complete a fully carbon-neutral voyage using alternative fuels.

Key Players

Established Leaders

Neste (Finland): World's largest SAF producer, 1.5 million tonnes annual capacity expanding to 2.2 million by 2026
A.P. Moller-Maersk (Denmark): Fleet of 25+ methanol-powered vessels ordered, $1.4 billion committed to green methanol supply
TotalEnergies (France): SAF production target of 1.5 million tonnes by 2030 across five facilities
Singapore Airlines: First Asia-Pacific carrier with binding SAF commitments, targeting 5% blend by 2030
Shell Aviation: Operating SAF blending at 18 airports globally, including Singapore and Amsterdam

Emerging Startups

LanzaJet (USA): Ethanol-to-SAF technology, $50 million Series A led by British Airways
Twelve (USA): Power-to-liquid CO₂ conversion, partnerships with Microsoft and Alaska Airlines
Amogy (USA): Ammonia-to-power systems for maritime, $150 million funding
Windship Technology (UK): Wind-assist propulsion systems claiming 30%+ fuel savings
Boundless Impact Research & Analytics (Singapore): LCA software for maritime emissions tracking

Key Investors & Funders

Breakthrough Energy Ventures: $2 billion committed across SAF and maritime decarbonization
AP Moller Capital: $1 billion green transition fund
Singapore Economic Development Board: $300 million Maritime Singapore Decarbonisation Blueprint
Japan Bank for International Cooperation: $10 billion ammonia supply chain financing
European Investment Bank: €500 million SAF infrastructure facility

Real-World Examples

1. Singapore Maritime Decarbonisation Centre

Singapore's $300 million initiative, launched in 2024, functions as a living laboratory for maritime decarbonization technologies. The centre coordinates trials of biofuel blends on container vessels, tests shore power systems at Jurong Port, and develops digital tools for emissions measurement, reporting, and verification (MRV). Early results show 15-20% fuel consumption reductions from AI-optimized routing. The centre has attracted participation from 40+ shipping companies and aims to certify Singapore-produced low-carbon ammonia by 2027.

2. Auckland Airport SAF Trial

Auckland Airport partnered with Air New Zealand and Fulcrum BioEnergy in 2024 to test municipal solid waste-derived SAF on domestic routes. The pilot processed 5,000 tonnes of household waste to produce 500,000 liters of SAF, achieving lifecycle emissions 80% below conventional jet fuel. Critically, the project demonstrated that waste-to-SAF pathways can achieve competitive costs ($4.20/gallon) in markets with high landfill tipping fees.

3. Maersk's Methanol Fleet Deployment

Maersk took delivery of the world's first large methanol-powered container vessel, the 16,000 TEU Ane Maersk, in February 2024. Operating between Asia and Europe, the vessel uses green methanol produced from agricultural waste and renewable electricity. Maersk has committed to 25 methanol-capable vessels by 2027 and secured 730,000 tonnes of green methanol supply agreements. The company estimates 25-30% cost premium for green methanol operations but anticipates parity by 2030 as production scales.

Sector-Specific KPIs

Metric	Current (2024)	Target (2030)	Target (2050)
SAF production (million tonnes)	1.0	15-20	350+
SAF cost premium vs. jet fuel	2-5x	1.5-2x	<1.5x
Maritime alternative fuel adoption	<1%	5-10%	80%+
Lifecycle emissions reduction (SAF)	60-80%	70%+	90%+
Green ammonia production cost ($/kg)	6.00	3.00	1.50
Vessels on order with alt-fuel capability	1,100+	3,000+	—

Action Checklist

Establish corporate SAF procurement targets with binding offtake agreements (minimum 3-year terms)
Implement full lifecycle assessment protocols for all decarbonization investments, including ILUC factors
Engage port authorities on shore power infrastructure and alternative fuel bunkering capabilities
Join industry coalitions (e.g., First Movers Coalition, Getting to Zero Coalition) to pool demand signals
Develop internal carbon pricing mechanisms that account for aviation and shipping exposure
Pilot digital MRV systems to establish baselines before mandatory reporting requirements take effect
Assess supply chain resilience to feedstock constraints in HEFA-dominant SAF market

FAQ

Q: Is SAF actually carbon-neutral? A: No. SAF reduces lifecycle emissions by 60-80% compared to conventional jet fuel, not 100%. The "sustainable" label reflects lower carbon intensity, not zero emissions. Power-to-liquid pathways using direct air capture and renewable hydrogen can theoretically achieve 90%+ reductions, but remain <1% of production.

Q: Why isn't battery-electric aviation viable for commercial routes? A: Energy density is the fundamental constraint. Jet fuel contains approximately 12,000 Wh/kg, while the best lithium-ion batteries deliver 250-300 Wh/kg. A battery with equivalent energy to a transatlantic flight's fuel load would weigh more than the aircraft itself. Battery-electric is emerging for short-haul routes (<500 km) but cannot serve medium- or long-haul segments.

Q: What's the difference between green ammonia and blue ammonia for shipping? A: Green ammonia is produced using renewable electricity to split water (electrolysis) and synthesize ammonia via the Haber-Bosch process, resulting in near-zero lifecycle emissions. Blue ammonia uses natural gas with carbon capture and storage (CCS), reducing emissions 60-90% depending on capture rates and methane leakage upstream. Green ammonia costs roughly $6/kg (2024) versus $2-3/kg for blue ammonia.

Q: How do book-and-claim SAF certificates work? A: Book-and-claim allows SAF environmental attributes to be transferred separately from physical fuel delivery. An airline can purchase SAF produced in Los Angeles and apply its carbon benefits to flights departing Singapore, even though the physical fuel was used in California. This mechanism enables SAF deployment at production sites before distribution infrastructure exists everywhere, but critics argue it delays infrastructure investment.

Q: Which Asia-Pacific ports are leading in maritime decarbonization? A: Singapore has invested most aggressively, with $300 million committed to its Maritime Decarbonisation Centre and plans for ammonia bunkering by 2027. Shanghai is piloting methanol bunkering for coastal ferries. Australia's Port of Newcastle is developing green hydrogen and ammonia export infrastructure. South Korea's Busan is testing shore power systems and has ordered ammonia-fueled tugboats.

Sources

International Energy Agency. (2024). Net Zero Roadmap: A Global Pathway to Keep the 1.5°C Goal in Reach. https://www.iea.org/reports/net-zero-roadmap-a-global-pathway-to-keep-the-15-0c-goal-in-reach
SkyNRG & ICF. (2025). Sustainable Aviation Fuel Market Outlook 2025. https://skynrg.com/safmo25/
International Maritime Organization. (2023). 2023 IMO Strategy on Reduction of GHG Emissions from Ships. https://www.imo.org/en/OurWork/Environment/Pages/2023-IMO-Strategy-on-Reduction-of-GHG-Emissions-from-Ships.aspx
Maritime and Port Authority of Singapore. (2024). Maritime Singapore Decarbonisation Blueprint. https://www.mpa.gov.sg/maritime-singapore/sustainability
European Commission. (2023). ReFuelEU Aviation Regulation. Official Journal of the European Union. https://eur-lex.europa.eu/eli/reg/2023/2405
MarketsandMarkets. (2025). Sustainable Aviation Fuel Market - Global Forecast to 2030. https://www.marketsandmarkets.com/Market-Reports/sustainable-aviation-fuel-market-70301163.html
DNV. (2024). Maritime Forecast to 2050: Energy Transition Outlook. https://www.dnv.com/maritime/publications/maritime-forecast-2024/
Boeing. (2024). Commercial Market Outlook 2024-2043. https://www.boeing.com/commercial/market/commercial-market-outlook

Myth-busting sustainable aviation & shipping: separating hype from reality (angle 7)