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We need massive amounts of carbon capture from air to decarbonize aviation, and policymakers must act now

At least 1.83 million tons per year (Mt/yr) of e-kerosene will be produced in Europe by 2030. The European Parliament’s draft of the main regulation supporting e-kerosene production and use in the European Union – the ReFuelEU Aviation – provides that 50% of all aviation fuel consumed in the EU needs to be synthetic by 2050. This would translate to producing several million tons of e-kerosene each year requiring significant quantities of sustainable CO2 for their production: at least 5.5 Mt/yr in 2030 and up to 70 Mt/yr in 2050[1].

In total, 99.9% of all jet fuel currently used in commercial aviation is of fossil origin. In line with climate goals, policymakers are designing regulation to get airlines off fossil jet fuel and onto low-carbon energy sources and energy carriers. New technologies such as hydrogen- or electricity-powered aircraft can reduce the dependency of the sector on fossil kerosene, with some studies suggesting that they could cover up to 40 percent of aviation fuel demand in 2050. However, there is uncertainty over their role, and there is broad consensus that the vast majority of air travel will need to be powered by some type of low-carbon liquid fuels at least until 2050.

To date, most work has gone into various types of biokerosene. However, when scaled-up, even the most sustainable biokerosene will create inescapable competition for arable land and food production. Additionally, the same feedstocks used for biokerosene production are strongly required in other sectors such as for the production of biodiesel in road transport or bioplastics. As a result, bio-kerosene is physically limited in quantity.

In a recent study conducted by the German Energy Agency (dena), LUT University and Ludwig-Bölkow Systemtechnik, we find that due to the limited availability of biokerosene and other technological alternatives, in a carbon-neutral global aviation sector in 2050, nearly 60 percent of fuel demand is covered by e-kerosene.

A major challenge is that e-kerosene requires significant quantities of sustainable or unavoidable feedstock CO2 for its production, and those CO2 sources are fairly limited.

Some so-called point sources of CO2 could be considered sustainable, in the sense of mainly emitting CO2 back to the atmosphere which has previously been drawn down from the atmosphere, such as pulp and paper mills. Other point sources that society might for now consider unavoidable, such as waste incinerators, can also be tapped to produce e-kerosene. However, as found in our work as well as other analyses (1, 2), all these point sources are very limited in quantity, highlighting the need for a scalable, environmentally sustainable source of CO2 for e-kerosene production.

A scalable solution to produce environmentally-sustainable CO2 is DAC, a class of technologies able to remove CO2 directly from ambient air.

A scalable solution to produce environmentally-sustainable CO2 is DAC, a class of technologies able to remove CO2 directly from ambient air. This has seen investment from large companies across the economy such as Airbus, Microsoft, Alphabet, Meta, Shopify, Swiss Re, as well as governments — the U.S. Department of Energy announced it would fund $3.5 billion of DAC projects – but the technology is still nascent, with just a handful of companies building DAC plants worldwide.

The required quantities of kerosene produced with CO2 from DAC, let’s call it ‘DAC-kerosene’, are significant. In our work, we find that DAC covers over 90 percent of CO2 demand for e-kerosene production in 2050 (the remainder coming from point sources), translating into a required DAC capacity for e-kerosene production in 2050 of 161 million tons a year (Mt/yr) to 281 Mt/yr of CO2 in Europe, and 102 Mt/yr to 176 Mt/yr in the U.S., depending on the availability of point sources.

To produce all the required DAC-kerosene domestically in 2050, the US would need to generate up to 1,250 TWh/yr of renewable electricity dedicated to DAC-kerosene production alone, and Europe up to 2,000 TWh/yr. Here too, the scale of the challenge is significant. Europe produced approximately 1,700 TWh/yr of renewable electricity in 2021 (based on 1 and 2, nuclear excluded) for all end-uses, meaning that by 2050 it would need to generate more than today’s entire renewable electricity generation to produce e-kerosene alone. The same is valid for the US, which produced 860 TWh of renewable electricity in 2021 (nuclear excluded).

If this seems challenging, consider the alternatives: DAC-kerosene requires 70 times less land than even one of the least land-intensive biokerosene (produced via the alcohol-to-jet pathway from sugarcane) and does not require any arable land at all.

We further find that the EU and the U.S. have more than enough renewable electricity potential to decarbonize their aviation sectors, using DAC fuels. As a result, DAC-kerosene production plants can be installed and scaled significantly as long as they can access water, air and electricity.

Given the need for DAC-kerosene, policymakers must design incentives that specifically favor DAC fuels, in order to make sure that demand is met while avoiding negative environmental side effects.

The EU should set dedicated quotas for e-kerosene made from carbon via DAC in the ReFuelEU Aviation regulation proposal, requiring at least 10 percent of feedstock CO2 for e-kerosene production to be sourced via DAC in 2030, increasing to 90 percent in 2050.

We have done the math on the most cost-effective route and find that the EU should set dedicated quotas for e-kerosene made from carbon via DAC in the ReFuelEU Aviation regulation proposal, requiring at least 10 percent of feedstock CO2 for e-kerosene production to be sourced via DAC in 2030, increasing to 90 percent in 2050.

Given our current crises of food insecurity, record heatwaves and the EU’s costly oil imports empowering autocratic regimes, we need to think smart across multiple fronts. DAC-kerosene offers the chance to do just that: With rigorous policy we can decarbonize aviation using DAC fuels, in a way that protects food security, avoids competition with other sectors and improves energy security with domestically-produced renewable energy.


[1] Derived from the ReFuelEU Aviation proposal impact assessment from 15.07.2021



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