{"id":167958,"date":"2025-09-23T07:20:00","date_gmt":"2025-09-23T05:20:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=167958"},"modified":"2025-09-16T13:00:14","modified_gmt":"2025-09-16T11:00:14","slug":"the-impossible-maths-of-sustainable-aviation-why-only-the-atmosphere-can-fuel-our-future","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/the-impossible-maths-of-sustainable-aviation-why-only-the-atmosphere-can-fuel-our-future\/","title":{"rendered":"The impossible maths of sustainable aviation: Why only the atmosphere can fuel our future"},"content":{"rendered":"\n\n\n

Sustainable aviation feels a lifetime away, with limited production of SAF, slow development of new airliners and an economic disconnect for investing in green technologies. Jean-Philippe Hiegel, VP Strategy & Growth at RepAir Carbon, discusses how we can turn the sky itself into a fuel source capable of powering the aviation industry sustainably:<\/a><\/p>\n\n\n\n

Aviation accounts for 2.5% of global energy-related\u00a0CO2 emissions<\/a><\/strong>\u00a0\u2013 nearly a gigaton annually \u2013 and is growing faster than rail, road or shipping. This sector represents one of the most challenging to decarbonise.\u00a0<\/p>\n\n\n\n

As the International Energy Agency notes, reaching net-zero will require \u201crevolutionary\u201d designs, including alternative propulsion technologies such as electric <\/a><\/strong>or hydrogen-powered aircraft.<\/p>\n\n\n\n

However, battery electric propulsion<\/a><\/strong> is currently limited to very small aircraft and short ranges. Using hydrogen poses significant challenges<\/a><\/strong>: innovative fuel storage and delivery methods, low-cost lightweight cryogenic tanks, and redesigned airframes to accommodate them. Questions about hydrogen\u2019s impact on contrails<\/strong><\/a> remain unanswered, with dedicated studies still underway.<\/p>\n\n\n\n

This technological reality makes sustainable aviation fuels (SAF) critical to decarbonising aviation now. Yet here too, there\u2019s a fundamental constraint that needs to be addressed \u2013 and urgently.<\/p>\n\n\n\n

SAF from biogenic feedstocks has fundamental limits<\/h3>\n\n\n\n

While the EU has set ambitious SAF blending targets<\/a><\/strong> \u2013 2% this year, rising to 6% by 2030 and 70% by 2050 with a synthetic fuel sub-mandate of 1.2% by 2030 and 35% by 2050 \u2013 the industry\u2019s current approach relies heavily on biogenic CO2 from crops, agricultural waste and other biological sources. And biogenic feedstocks have inherent limitations that make these targets mathematically impossible.<\/p>\n\n\n\n

The EU\u2019s RefuelEU<\/a><\/strong> regulation excludes SAFs produced from food and feed crops due to sustainability concerns. While biojet kerosene from animal fat and waste oil feedstocks are included, their growth potential is limited by supply. <\/p>\n\n\n

\n
\"RAF
\u00a9 Nick Morrish \/ British Airways<\/figcaption><\/figure><\/div>\n\n\n

More abundant feedstocks could come from agricultural residues, dedicated energy crops and municipal solid waste \u2013 but even these face constraints.<\/p>\n\n\n\n

First, cultivating crops for fuel creates direct land use competition with food production or requires land conversion. Second, and more critically, biogenic sources are finite. <\/p>\n\n\n\n

Meeting the EU\u2019s 2050 SAF targets through biogenic sources alone would require between 7% and 18% of today\u2019s EU agricultural land, depending on the feedstock. It\u2019s both impractical and impossible at the scale needed. <\/p>\n\n\n\n

Even if we maximised every available biogenic source globally, we\u2019d fall short of the gigatons of CO2 needed for aviation fuel production by 2050.<\/p>\n\n\n\n

This is where atmospheric CO2 becomes essential. <\/p>\n\n\n\n

Direct Air Capture: Sustainable aviation fuel from the sky<\/h3>\n\n\n\n

Direct Air Capture (DAC)<\/a><\/strong> allows us to capture CO2 needed to produce e-SAF \u2013 synthetic fuels made by combining atmospheric CO2 with green hydrogen produced by electrolysers run on low-emissions electricity through processes like Fischer-Tropsch or methanol-to-jet conversion.<\/p>\n\n\n\n

The key advantage is unlimited feedstock: the atmosphere contains all the CO2 we need. We\u2019re not talking about offsetting here \u2013 this is about recycling; creating a circular carbon economy where aviation\u2019s emissions become tomorrow\u2019s fuel.<\/p>\n\n\n

\n
\"Direct
Infographic \u00a9 Airbus<\/figcaption><\/figure><\/div>\n\n\n

RefuelEU Aviation regulation already recognises this distinction, segregating between biogenic SAF and e-SAF from direct air capture. This is an acknowledgement that atmospheric carbon represents a fundamentally different resource with fundamentally different potential.<\/p>\n\n\n\n

What makes this pathway particularly promising is also infrastructure compatibility. Airports in Rome and Paris are already preparing for e-fuel supply chains. Unlike hydrogen or electric alternatives that would require complete infrastructure overhauls, e-SAF uses existing fuel systems. <\/p>\n\n\n\n

That\u2019s a massive advantage for an industry that needs solutions now, not in ten years.<\/p>\n\n\n\n

Cutting the cost of carbon capture through electrochemical innovation<\/h3>\n\n\n\n

The cost challenge is real but not insurmountable. Traditional DAC<\/a><\/strong> technologies have struggled with high energy requirements \u2013 often consuming 2,500 kWh or more per tonne of CO2 captured. <\/p>\n\n\n\n

But innovation is rapidly changing this equation. New electrochemical approaches can achieve up to 70% lower energy consumption compared to conventional thermal-based systems. <\/p>\n\n\n\n

By eliminating the need for high-temperature processes and chemical solvents, these technologies can reduce both operational costs and capital requirements. When you factor in mass manufacturing potential using standard materials rather than exotic components, the path to cost-competitive atmospheric CO2 becomes clear. <\/p>\n\n\n

\n
\"A
\u00a9 RepAir Carbon<\/figcaption><\/figure><\/div>\n\n\n

The same innovation curve that brought battery costs down by 90% over the past decade is beginning to transform DAC.<\/p>\n\n\n\n

But we need to be honest about the challenge: the entire e-SAF value chain \u2013 from DAC to hydrogen production to fuel synthesis \u2013 requires substantial energy inputs. Current e-SAF costs five to six times more than conventional jet fuel. <\/p>\n\n\n\n

Building a SAF production plant takes 10 to 20 years to reach full operational scale. This is why it\u2019s a day-one challenge. The plants we need operational in 2040 must break ground today.<\/p>\n\n\n\n

Aviation\u2019s sustainable future must include atmospheric carbon <\/h3>\n\n\n\n

The truth is that from a pure energy efficiency standpoint, the numbers might favour simply capturing CO2 and storing it underground. <\/p>\n\n\n\n

But Europe \u2013 and other countries such as the UK, Brazil and Japan \u2013 have chosen a different path, for better or for worse: pushing the industry to innovate beyond the World War II-era Fischer-Tropsch process, to find new pathways that make recycled carbon economically viable.<\/p>\n\n\n\n

For this to happen, I believe three critical developments must happen:<\/p>\n\n\n\n

    \n
  • First<\/strong>: Reinforce supply-side and demand-side policies to scale up e-SAF production and offtake<\/li>\n\n\n\n
  • Second<\/strong>: Tax aviation fuels according to their climate impact, acknowledging that only a minority of the world flies<\/li>\n\n\n\n
  • Third<\/strong>: Position aviation as a lead market to bring nascent decarbonisation options to commercial scale. Actions from leading airlines and airports that serve as key international and domestic hubs can generate the market pull needed to catalyse the adoption of efficient operations and best-in-class technologies<\/li>\n<\/ul>\n\n\n\n

    E-SAF from atmospheric CO2 doesn\u2019t compete with biogenic SAF \u2013 we need every sustainable fuel source available, but only atmospheric carbon offers the unlimited scale required for aviation\u2019s future.<\/p>\n\n\n\n

    It\u2019s time we acknowledge that aviation\u2019s sustainable future depends on turning the sky itself into our fuel source.\u00a0<\/p>\n\n\n\n

    <\/div>\n\n\n\n

    About the Author<\/h3>\n\n\n
    \n
    \"Jean-Philippe
    \u00a9 RepAir Carbon<\/figcaption><\/figure><\/div>\n\n\n

    Jean-Philippe Hiegel is the VP Strategy & Growth at RepAir Carbon and has deep expertise in carbon capture and storage, carbon dioxide removal, large project development, and decarbonization strategy. At RepAir,\u00a0he leads business development, international partnerships, and commercial scaling of its electrochemical carbon capture technology.\u00a0<\/em><\/p>\n\n\n\n

    <\/div>\n","protected":false},"excerpt":{"rendered":"

    Sustainable aviation feels a lifetime away, with limited production of SAF, slow development of new airliners and an economic disconnect for investing in green technologies. Jean-Philippe Hiegel, VP Strategy & Growth at RepAir Carbon, discusses how we can turn the sky itself into a fuel source capable of powering the aviation industry sustainably: Aviation accounts […]<\/p>\n","protected":false},"author":59,"featured_media":167973,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","nova_meta_subtitle":" How we can turn the sky itself into a fuel source capable of powering the aviation industry sustainably","footnotes":""},"categories":[5571],"tags":[10794,10744,21452,13911,22172,10630,16792,10743],"supplier":[155,2317,8202,24718],"class_list":["post-167958","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-co2-based","tag-aviationfuel","tag-carboncapture","tag-carbonstorage","tag-electricity","tag-esaf","tag-hydrogen","tag-saf","tag-useco2","supplier-airbus","supplier-european-commission","supplier-iea-bioenergy","supplier-repair-carbon"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/167958","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=167958"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/167958\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media\/167973"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=167958"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=167958"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=167958"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=167958"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}