Direct Air Capture (DAC) is considered an important technology for the long-term production of Sustainable Aviation Fuel (eSAF) as it provides a scalable and reliable source of carbon dioxide (CO₂) that does not depend on biological feedstocks or industrial emissions.
Need for a Sustainable Carbon Source to Make eSAF
Along with green hydrogen produced using low-carbon electricity, a carbon source is required to synthesise liquid eFuels suitable for aircraft engines. And that should be a sustainable, secure, scalable and verifiable source of CO₂ to meet long-term aviation fuel demand.
Current SAF production methods often rely on waste oils and fats, agricultural biomass or point source industrial CO₂ emissions.
Why Point Source and Biomass CO₂ Sources for SAF are Limited
These sources are not ideal as:
- Waste feedstocks are limited in volume.
- Biomass competes with land use, food production, and biodiversity.
- Industrial CO₂ sources are bound by location and CO₂ purity is a supply risk.
Furthermore, if waste oils or biomass are used, supply volumes can’t be increased in line with projected eSAF demand without creating pressure on food systems and biomass markets.
DAC provides an alternative carbon supply by removing CO₂ directly from the atmosphere, which is effectively unlimited at the scale required for global aviation, and DAC systems can be located at the eSAF production site.
DAC Enables Large Scale Synthetic Fuel Production (eSAF)
In eSAF production, captured atmospheric CO₂ is combined with green hydrogen produced via electrolysis to create synthetic hydrocarbons.
The overall concept is a closed carbon loop:
- CO₂ is captured from ambient air.
- Hydrogen is produced using low-carbon electricity.
- CO₂ and hydrogen are converted into liquid fuel.
- Fuel combustion releases CO₂ back into the atmosphere.
Because the carbon originated from the atmosphere, the process forms a closed carbon cycle rather than introducing new fossil carbon, which makes the flight carbon net-zero. Without DAC, large-scale eSAF production would depend on industrial CO₂ sources, which limits scalability and long-term sustainability.
Using Low-Grade Waste Heat from Hydrogen Electrolysers
Electrolysers generate low-grade waste heat during hydrogen production. Instead of letting this energy go unused, DAC systems can harness it to power their CO₂ capture processes. This co-location reduces the operating costs of DAC while making better use of the total energy input into the site. The captured CO₂ and green H₂ can then be synthesised into SAF via Fischer–Tropsch or other suitable processes, all on a single integrated site, which cuts down on emissions and transport costs.
Long-Term Aviation Decarbonisation
Aviation is difficult to electrify due to energy density requirements for long-haul flight. Liquid hydrocarbon fuels remain necessary for long-distance commercial aviation, cargo transport and the existing aircraft fleets.
To this end, DAC enables production of drop-in fuels compatible with current aircraft while reducing lifecycle emissions, which makes DAC a key enabling technology for sectors where direct electrification is not feasible.
DAC Delivers Both Feedstock for eFuel Production and Carbon Removal
DAC systems can also provide dual value in that they provide carbon removal for climate mitigation markets as well as CO₂ feedstock for fuel synthesis.
This creates economic opportunities through several avenues:
- Carbon credits
- Fuel production revenue
- Industrial CO₂ supply
Final Thought
Strategic Role of DAC in Net-Zero Aviation
Global aviation demand exceeds the sustainable supply potential of biomass-based fuels, whereas DAC enables a pathway to produce aviation fuel at the scale required without exceeding ecological limits.
For this reason, DAC is widely considered a critical technology for achieving net-zero aviation emissions by mid-century. Direct Air Capture addresses these issues by decoupling CO₂ supply from emission sources, enabling location flexibility, consistent purity, and alignment with long-term net-zero aviation objectives. When powered by near-zero carbon energy, DAC-derived CO₂ provides a durable and auditable carbon input for eSAF production.
For more:
- Sustainable Aviation Fuel
- How is Sustainable Aviation Fuel Made?
- How does SAF Reduce Emissions?
- SAF vs Jet Fuel
- SAF Regulations
- What is eFuel?
- What is eMethanol?