Decarbonising aviation fuels

The above measures are estimated to bring down the sector’s fuel demand from

71.3 Mtoe under a BaU, to 59.2 Mtoe. Decarbonising aviation by 2050 will therefore depend on decarbonising that remaining fuel demand. We look at two pathways to do this - deploying sustainable advanced biofuels, and renewable fuels of non-biological origin (RFNBO).

Advanced biofuels

Advanced biofuels are defined as biofuels produced from waste and residues. The issues with many, particularly first generation, biofuels are well documented. Europe’s experience with mandates for the road transport sector demonstrated that many of the biofuels used resulted in total emissions which were greater than the fossil fuels they replaced (Transport & Environment, 2018). This was due to what is known as indirect land use change - the use of land to grow crops for biofuels displaces land which was previously used to grow crops for food. This displacement sparks further deforestation and conversion of grassland to ensure sufficient land is cultivated for both fuel and food and an increase in emissions. In addition, even if we were to ignore these Indirect Land Use Change (ILUC) effects, the amount of land required to produce significant volumes of aviation biofuels would be enormous. (Powering the world’s aviation fully with biofuels in 2050 would, directly or indirectly, require more than 3.5 million km² of land;T&E’s own calculations indicate that international aviation will consume around 800 Mt of fuel in 2050.The NCV of kerosene is

44.1 TJ/kt.That equals 35.28 EJ = 843 Mtoe by 2050. IHa produces 100 GJ of biofuel.) This would run counter to the efforts to increase negative emissions and carbon sinks, which will be required as part of the Paris Agreement.

• 80
• 70

• 4.3
• 5.8
• 59.2

Aviation fossil energy demand, Mtoe in 2050

Remaining energy demand, covered by fossil

• Reduction from €150/tCO2 carbon price

Reduction from Gen II aircraft from 2040

Reduction from 0.2% p.a. improvement conventional fleet

Figure 9.2 Contributions of technology, operational efficiency, and carbon pricing on kerosene demand in 2050. Note that 59.2 Mtoe of kerosene is 183 Mt CO,, approximately equivalent to business as usual 2025 emissions.

We limit our availability forecast to only those advanced biofuels from waste and residues which deliver real and sustainable reductions in emissions. Such feedstocks are incidental to other processes and so will be limited in availability. Our projection is that in 2050, availability of sustainable advanced biofuels for the aviation sector will total 7500 kilotonnes of oil equivalent (ktoe), meeting 11.4% of European aviation fuel demand (if the above efficiency and carbon

Roadmap to decarbonising aviation 157 pricing measures are realised; otherwise, advanced biofuels could make up to 10.5% of BaU oil demand).

This is based on previous T&E research on the future availability of sustainable advanced biofuels (Transport & Environment, 2017a). In making this projection, our assumption is that other sectors, particularly road transport, will have transitioned entirely to direct electric or renewable hydrogen propulsion and by 2050 won’t need to decarbonise through the use of alternative fuels.

Sustainable advanced fuels will contribute to decreasing greenhouse gas (GHG) emissions, but there are not so many which show pathways towards zero or negative emissions through their life cycle. If some fuels, for example, achieve 80% emission reductions, then their use will still result in emissions from the sector; i.e. not achieve decarbonisation. To contribute to the decarbonisation of aviation, their production and entire life-cycle impact (including indirect impacts) must be zero carbon.Therefore, decarbonising aviation is coupled with broader efforts to decarbonise the economy, as reducing the carbon intensity of other activities such as heat, industrial processes and electricity generation will help reduce the lifecycle emissions from advanced biofuels. It is crucial for EU policies to account for all GHG emissions (also indirect) from advanced fuels. For accounting purposes, we assign zero emissions to these fuels in our modelling exercise.

Our forecast is that an availability of 7500 ktoe of alternative fuels will contribute to reducing fossil kerosene demand by 6.8 megatonnes of oil equivalent (Mtoe) — or 11.4% — of aviation fuel demand in 2050 (an increasing uptake or blend of biofuel will reduce the CO, price, and the associated demand reduction.