Sustainable Aviation Fuel and Its Role in Advanced Air Mobility

There are more solutions than obstacles. Nicolas Zart

Making sense of the potential of sustainable aviation fuel (SAF) promises can be complicated in this world of highly marketed articles. SAF has the potential to not only pave the way for a smaller carbon footprint in the advanced air mobility (AAM) industry but also for the entire conventional aviation world. The conventional aviation replacement is a drop-in fuel that is compatible with existing aircraft engines and infrastructure. This means it can be replaced without having to do anything on aircraft engines or ground infrastructure.

Not everyone knows or understands that aviation only contributes about two to three percent of global carbon dioxide emissions. This is very small compared to the automotive industry, estimated at 30% of global emissions, topped only by the maritime industry, weighing in at a whopping 60+%. However, growth in air travel is predicted to increase this share. SAF offers a potential pathway to reduce the climate impact of aviation, including emerging sectors such as advanced air mobility. SAF is produced from renewable or waste-based feedstocks, enabling lifecycle greenhouse gas reductions approaching seventy percent compared to conventional jet fuel derived from fossil sources.

Global Emission Reductions and Efficiencies

The International Air Transport Association (IATA) aims for seventy percent SAF usage by 2050 to meet net-zero emissions goals adopted globally, with support from the International Civil Aviation Organization (ICAO). Despite this ambition, SAF currently meets less than one percent of the global jet fuel supply. This gap results from limited manufacturing capacity, high production costs, and technology maturity challenges.

The SAF industry recently suffered from high-impact press releases from an enthusiastic airline industry years ago, eager to recoup time lost with the COVID-19 travel decline, only to be unceremoniously dropped over the past two years. Since then, several ASTM International-approved production pathways have transformed various biological and waste materials into SAF. The Hydroprocessed Esters and Fatty Acids (HEFA) pathway converts used cooking oils and animal fats into jet fuel and is the most commercially mature process. However, the limited availability of suitable feedstock restricts long-term scalability.

The Fischer-Tropsch synthesis process offers the ability to convert biomass or municipal waste into jet fuel but requires significant capital investment and has variable carbon intensity depending on feedstock and energy sources. Alcohol-to-Jet (ATJ) technology is gaining traction as a scalable route, converting ethanol—made from diverse sources including cellulosic biomass and municipal waste—into jet fuel.

LanzaJet, a leading company in SAF innovation, uses the ATJ process to produce SAF from renewable ethanol. Their commercial plant, Freedom Pines Fuels in Georgia, USA, produces millions of gallons of SAF annually, exemplifying a scalable model leveraging existing ethanol supply chains. LanzaJet’s partnership with LanzaTech through CirculAir combines carbon recycling technologies to produce renewable ethanol from industrial emissions, enhancing sustainability and feedstock diversity.

Government Push To Kindle Corporate Efficiency

Government policies underpin SAF market growth, hoping to spur corporate interest, helping make this mobility world more efficient and, by the same token, less polluted. In the European Union, the ReFuelEU Aviation initiative mandates increasing SAF blend requirements up to seventy percent by 2050. The United States offers tax credits, the Sustainable Aviation Fuel Grand Challenge, and various state incentives aimed at expanding domestic SAF production. Other countries, including Japan, Canada, and Australia, have enacted SAF mandates and incentives reflecting net-zero commitments.

Research from the Department of Energy’s Bioenergy Technologies Office and National Renewable Energy Laboratory highlights the technical potential and emissions benefits of SAF. All report the same challenges in cost reduction and feedstock availability. Studies published in the Journal of Cleaner Production and Environmental Science & Technology underscore the importance of sustainable feedstock sourcing to avoid indirect land use change and ensure net environmental benefits.

Globally, airlines including United, Delta, and KLM have trialed SAF blends on commercial routes while manufacturers like Boeing and Airbus support SAF as a key emissions reduction lever. However, most have abandoned SAF, citing the same lack of manufacturing concerns after triumphant press releases a few years ago. For AAM, SAF provides an immediate route to decarbonization compatible with existing propulsion technologies as the sector develops electric and hybrid-electric systems for “flying cars” and urban “air taxis”.

Aviation emissions are a complex challenge demanding multiple solutions. SAF stands out by offering a near-term, scalable, and infrastructure-compatible decarbonization technology. Continued investment, policy support, and innovation in feedstock development and conversion technologies will be essential to unlock SAF’s contribution to a sustainable aviation future. As with any disruptive technology, critical mass production is key to its success. Hopefully, the correct blend of government incentives backed by corporate stewardship will make SAF mainstream.

Sustainable Aviation Fuel and Its Role in Advanced Air Mobility