Decarbonizing Aviation: Challenges and Opportunities for Emerging Fuels

The aviation sector contributes 2% of global CO2 emissions, with projections suggesting these could triple by 2050 without policy intervention. While Sustainable Aviation Fuels (SAFs) are the primary current solution, the report argues that the term is imprecise and that relying solely on biofuels would require quadrupling global production by 2030 and quintupling it by 2040, posing severe risks to land use, biodiversity, and food security. To meet projected global energy demands of 15.9 quads in 2030 and 21.5 quads in 2050, the report advocates for a shift toward scalable zero-emission fuels (SZEFs)—including hydrogen and synthetic fuels created via direct air capture (DAC)—and electric propulsion. It provides specific policy recommendations for the U.S. and EU, including RD&D investments, carbon intensity standards, and the phasing out of free emission allowances.

• The aviation sector's CO2 emissions grew by 30% between 2013 and 2019, reaching 920 Megatons (Mt), and were on track to triple by 2050 before the COVID-19 pandemic.
• The term 'Sustainable Aviation Fuels' (SAFs) is criticized as being imprecise and misleading because it often conflates biofuels with truly sustainable options and excludes other energy carriers like hydrogen and battery electric propulsion.
• Meeting projected global aviation energy demand using only biofuels would require an unrealistic scale-up of production, increasing from 3.65 quads per year to 15.9 quads by 2030 and 21.5 quads by 2050.
• Massive expansion of biofuel production poses significant environmental and social risks, including land use change (LUC), biodiversity loss, and increased food insecurity.
• Synthetic fuels produced from CO2 captured via direct air capture (DAC) and hydrogen are a viable 'drop-in' alternative to kerosene, though they currently face high costs and energy requirements.
• Electric propulsion is limited to small aircraft and short distances due to the low energy density of current battery technology, which is approximately 14 times less dense than conventional jet fuel.
• Hydrogen propulsion eliminates in-flight CO2 emissions but faces economic hurdles, with short-range aircraft in 2040 potentially seeing operating costs increase by 25% per passenger compared to kerosene.
• The report argues that nature-based offsets, such as those used in ICAO's CORSIA scheme, carry substantial risks regarding permanence, leakage, and the albedo effect.
• U.S. policy is currently fragmented; the report recommends establishing a zero-carbon aviation energy mandate and a national zero-carbon fuel standard (ZCFS) to accelerate demand for SZEFs and electric propulsion.
• The EU's ReFuelEU Aviation proposal sets a blending mandate for SAFs starting at 2% in 2025 and reaching 63% by 2050, but critics suggest it overestimates the availability of sustainable waste-based feedstocks.

APA

Merchant, N., Kent, E., & Lewis, J. (2022). Decarbonizing Aviation: Challenges and Opportunities for Emerging Fuels. Clean Air Task Force. https://cdn.catf.us/wp-content/uploads/2022/09/13101935/decarbonizing-aviation.pdf

Chicago

Merchant, Na’im, Emily Kent, and Jonathan Lewis. Decarbonizing Aviation: Challenges and Opportunities for Emerging Fuels. Clean Air Task Force, 2022. https://cdn.catf.us/wp-content/uploads/2022/09/13101935/decarbonizing-aviation.pdf.

Wikipedia

{{cite report |last1=Merchant |first1=Na’im |last2=Kent |first2=Emily |last3=Lewis |first3=Jonathan |title=Decarbonizing Aviation: Challenges and Opportunities for Emerging Fuels |publisher=Clean Air Task Force |date=September 2022 |url=https://cdn.catf.us/wp-content/uploads/2022/09/13101935/decarbonizing-aviation.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{merchant2022decarbonizing, author = {Merchant, Na’im and Kent, Emily and Lewis, Jonathan}, title = {{Decarbonizing Aviation: Challenges and Opportunities for Emerging Fuels}}, institution = {Clean Air Task Force}, year = {2022}, month = sep, url = {https://cdn.catf.us/wp-content/uploads/2022/09/13101935/decarbonizing-aviation.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }