What Is eSAF? A Guide to Electro-Sustainable Aviation Fuel

Written By Kaitlyn Futch

The aviation industry accounts for roughly 2–3% of global CO₂ emissions, and demand for flights continues to grow. Unlike ground transportation, aviation can’t easily switch to batteries or hydrogen tanks because of weight and range constraints. That’s why sustainable aviation fuel (SAF) is widely recognized as one of the most impactful ways to decarbonize air travel in the near term.

Among the different types of SAF, eSAF (electro-sustainable aviation fuel) is emerging as a breakthrough solution. By combining captured CO₂, renewable electricity, and water, eSAF delivers a drop-in aviation fuel that works with today’s aircraft engines and fueling infrastructure while reducing lifecycle emissions.

What is eSAF?

eSAF, or electro-sustainable aviation fuel, is a synthetic aviation fuel designed to replace conventional petroleum-based jet fuel. Unlike fossil fuels, it is produced using sustainable inputs:

  • CO₂ captured from industrial facilities or other sources.

  • Renewable power (wind, solar, hydro, etc.).

  • Water for green hydrogen production.

The result is a product chemically identical to today’s aviation fuel that can be blended with existing fossil jet fuel, enabling airlines to decarbonize without waiting for new aircraft technology.

But doesn’t that fuel still get burned in the jet engines, releasing emissions? Yes, but the eSAF process recycles carbon rather than releasing new carbon into the atmosphere during its production, which is why it’s considered a net-zero carbon solution.

How is eSAF Made?

The production of eSAF starts with three key feedstocks: renewable power, water, and carbon dioxide (CO₂). By combining these sustainable inputs, Infinium transforms waste and clean energy into ultra-low-carbon jet fuel, a synthetic hydrocarbon fuel that meets today’s specifications.

  1. Carbon Dioxide Capture

    Anthropogenic CO₂, captured from industrial facilities or biogenic sources, is repurposed as a valuable input. Instead of being released into the atmosphere, these emissions become the carbon foundation for fuel production. It’s your “carbon” in hydrocarbon fuels.

  2. Green Hydrogen Production

    Renewable electricity powers electrolyzers that split water into hydrogen and oxygen. This green hydrogen is essential to creating synthetic fuels and ensures the process is powered by clean energy. It’s your “hydro” in hydrocarbon fuels.

  3. Fuel Synthesis

    Infinium’s proprietary technologies combine CO₂ and green hydrogen into syngas, which is then refined into ultra-low-carbon liquid fuels such as eSAF (sustainable aviation fuel), eDiesel, and eNaphtha.

This process is more than theory. It’s already proven at scale. Infinium’s Project Pathfinder in Texas is the world’s first operational commercial eFuels facility, producing today.

Why Does eSAF Matter for Aviation?

Aviation is one of the most challenging sectors to decarbonize. With growing passenger demand and limited alternatives to liquid fuels, airlines face mounting pressure to act. At the same time, governments around the world are rolling out ambitious SAF mandates:

Meeting these requirements involves a fuel that is not only low-carbon but also practical for airlines to adopt at scale.

Today, the production of SAF remains small relative to global fuel demand. In 2024, global SAF production hit a record 1 million tonnes, yet this represented only about 0.5% of total jet fuel consumption. The HEFA-based SAF produced today is valuable and needed, but it’s challenged with feedstock scale and, in certain regions, concerns over land use and compliance.

eSAF addresses these challenges because it is made from renewable power, water, and captured CO₂, and it offers a scalable pathway that can be deployed wherever these resources are available. eSAF is a drop-in solution: it can be used in existing aircraft engines and fueling infrastructure without costly infrastructure changes, making it an accessible tool for airlines looking for alternatives to fossil-based jet fuel.

Most importantly, eSAF delivers a significant lifecycle CO₂ reduction by recycling emissions into new fuel, helping airlines cut their carbon footprint while continuing to meet global demand for air travel.

eSAF vs. SAF: What’s the Difference?

While all SAF is considered sustainable aviation fuel, not all SAF is produced in the same way.

  • Bio-based SAF → produced from feedstocks like used cooking oil, tallow, or biomass.

  • AtJ (alcohol to jet) → produced from alcohols such as ethanol and methanol.

  • eSAF → produced using CO₂ and renewable electricity.

Why eSAF stands out:

  • Doesn’t compete with food crops or agricultural land.

  • Can scale in regions without large biomass resources.

  • Offers long-term carbon reduction with a circular carbon cycle.

This makes eSAF one of the most future-proof solutions for the aviation sector.

The Market Imperative: SAF Mandates Driving Adoption

Global SAF mandates are reshaping the aviation landscape. Airlines are adopting sustainable fuels not only to meet regulatory requirements, but also to strengthen brand reputation and respond to growing customer and investor expectations for credible climate action.

As these policies tighten and public awareness increases, demand for scalable, low-carbon fuel is accelerating. For many carriers, securing a reliable eSAF supply has become a strategic move, supporting compliance, competitiveness, and brand leadership in sustainability.

Why Infinium?

Infinium is one of the only companies in the world producing eFuels at scale today. Our technology converts captured CO₂, renewable power, and water into drop-in fuels that work seamlessly with existing aircraft and fueling systems.

With Project Pathfinder, the world’s first operational commercial eFuels facility, in Texas, and Project Roadrunner under construction in West Texas, Infinium is proving that low-carbon flight is possible now, not decades from now.

Backed by global partners including Brookfield Asset Management, Breakthrough Energy Catalyst, and major airlines such as American Airlines and IAG, Infinium is scaling production to help aviation meet climate goals, comply with emerging mandates, and advance toward a net-zero future

Kaitlyn Futch