Has the economics of carbon capture in aviation reached a turning point?
With full climate impact accounting, e-fuels emerge as a cost-effective solution.
A study by researchers at ETH Zürich, published in the journal “Nature Communications”, has revealed that producing synthetic aviation fuel from captured carbon dioxide could be more economically viable than previously thought, particularly when accounting for aviation's total climate impact, including non-CO2 effects, such as contrails.
The research shows that choosing between different carbon removal approaches – using it as an e-fuel feedstock or storing it in the ground – depends on your climate goals.
Direct Air Carbon Capture and Storage (DACCS) is often discussed as a potentially economical pathway for addressing CO2 emissions, particularly if the goal is achieving CO2 neutrality while continuing the use of fossil fuel-based kerosene.
For example, Robert Hoglund of the Milkywire Climate Transformation Fund has argued that capturing and storing CO2 (DACCS) is cheaper than using that same CO2 to make e-fuels, highlighting the lower electricity demand of DACCS. Climeworks CEO Dr Christoph Gebald echoed this point in his interview on our “Sustainability in the Air” podcast, emphasising the potential cost-effectiveness of DACCS in achieving CO2 neutrality.
However, the economics shift significantly when you account for aviation's full climate effects – particularly contrails, which researchers at Imperial College London have found can have a warming effect greater than all the CO2 emitted by aircraft. As Dr Edward Gryspeerdt from Imperial's Grantham Institute notes, “The warming effect of contrails is more than half the total climate impact of aircraft.”
The study finds that synthetic fuels produced through Direct Air Capture and Utilisation (DACCU) could be more cost-effective than DACCS by approximately €0.40 per litre when aiming for complete climate neutrality.
This potential advantage emerges primarily because alternative fuels appear to produce fewer warming contrails than conventional jet fuel, meaning less additional carbon removal would be needed to achieve climate neutrality.
Though the researchers note that this cost advantage depends on several factors, including the extent of contrail reduction and future energy costs, this finding could challenge previous assumptions about the most cost-effective path to sustainable aviation.
The cost evolution
"To achieve climate targets, which essentially means net zero by 2050, we need two things to happen," said Dr Gebald. "The first one is massive emission reductions, which account for roughly 90% of the exercise we have to do. Now, no matter how hard we reduce our CO2 emissions, the understanding is that we'll be sitting roughly on a pillar of 10% of so-called hard-to-abate emissions that have to be removed from the atmosphere."
While Climeworks expects DAC costs to drop to $100-200 per tonne by 2040, some innovators suggest even more dramatic cost reductions might be possible.
Israeli startup RepAir Carbon Capture claims its novel electrochemical process could capture carbon dioxide using just one-quarter of the energy required by current technologies. The company is targeting costs of around $70 per tonne – representing a dramatic improvement from today's $300-500+ per tonne range if achieved.
The company's innovative use of recycled polypropylene instead of expensive metals for key components could help standardise and streamline both DACCS and DACCU deployment.
Rapidly falling renewable energy costs are enhancing these technological advances. Data from the International Renewable Energy Agency (IRENA) shows that solar power costs have plummeted 90% since 2010 to $0.044 per kilowatt-hour, while wind power has dropped 70% to $0.033/kWh.
Cost impact: from short-haul to long-haul
The ETH Zürich study also provides a detailed breakdown of how decarbonisation costs would impact different flight routes.
The researchers estimate that carbon neutrality could add approximately €23 to the ticket using DACCS for short-haul flights like London-Berlin. Their modelling suggests DACCU (DAC + e-fuels) would be about €10 cheaper than DACCS when accounting for full climate impacts.
With DACCU, medium-haul routes like London-New York would see increases of €20-60. The largest impact is on ultra-long-haul routes like London-Perth, where costs could increase by up to €260, though DACCU could save passengers about €90 compared to DACCS when addressing total climate effects.
Notably, the authors point out that increases are smaller than some seasonal fare variations – the difference between booking two weeks versus two months in advance can be 400% for London-Berlin; over 100% for London-New York; and 70% for London-Perth.
The scale challenge
However, these improvements face a significant challenge: aviation's continued growth. "The numbers leave you speechless. The aviation industry's plans for growth are completely irreconcilable with Europe's climate goals and the scale of the climate crisis," says Jo Dardenne, aviation director at Transport & Environment (T&E).
The organisation has released an analysis showing European aviation plans to double passenger traffic by 2050, potentially overwhelming even the most optimistic technological improvements, and claiming that as a result, the impact of the SAF mandates will be minimal.
A portfolio approach
This growth challenge might require a more comprehensive solution combining multiple approaches where DACCU and conventional CDR methods work together. CO2 could be used as an e-fuels feedstock, while CO2 removals and storage work alongside it.
In his interview, Dr Gebald talked about how Climeworks has already expanded its offering beyond pure DAC to include other carbon removal methods like biochar and afforestation, providing customised portfolios to help companies meet their climate goals. Combined approaches could help address both direct emissions and broader climate impacts while managing costs.
The ETH Zürich study also identifies key conditions that could make synthetic fuels even more competitive:
Access to low-cost renewable electricity (€0.02/kWh),
Higher conventional jet fuel prices (€0.88/L),
Implementation of comprehensive climate impact policies,
Strategic deployment in regions with abundant renewable resources.
Major airlines are already positioning themselves for this transition. British Airways has committed over £9 million to purchase carbon removal credits, while Lufthansa Group has partnered with Climeworks through 2030. American Airlines has contracted with CDR firm Graphyte for 10,000 tonnes of carbon removal, while United is an investor in carbon capture company Svante.
The path forward
The convergence of falling DAC costs, improving renewable energy economics, and a growing understanding of aviation's full climate impact suggest the industry may be approaching a tipping point.
While DACCS currently offers a more economical path to pure CO2 reduction, the additional benefits of synthetic fuels in addressing aviation's total climate impact could make DACCU the more cost-effective long-term solution for true climate neutrality.
The choice between pathways will likely depend on factors beyond pure cost considerations, including renewable energy availability, carbon storage infrastructure, policy incentives, and airlines' strategic preferences. The key challenge now is not technological feasibility but achieving deployment at the scale needed to meaningfully impact aviation's climate footprint while managing the industry's growth trajectory.
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