European aviation’s road to decarbonization
23.08.2022 — Dan Kreibich on behalf of SQUAKE
Decarbonization has affected an increasing number of transportation modes around the globe. Some industries are managing to deal with these changes while others are struggling to adapt. For instance, the automotive industry has managed to switch to electric vehicles while the aviation industry’s success regarding sustainability has been somewhat stagnant. Much is being done to make the aviation industry more sustainable, despite considerable roadblocks on the way. In 2021, the International Air Transport Association (IATA) aimed for net-zero emissions by 2050 within the industry, which is more ambitious than previously planned. Achieving this goal will require the combined efforts of manufacturers, carriers, and governments.
This article is the first of a series of six to shed some light on the current status of passenger air traffic-related carbon emissions.
The research team at SQUAKE divided its research as follows:
- gathering and studying background information on CO2 emitted by air travel and the steps taken by public authorities toward reducing these emissions
- overview of the different CO2 emission calculation methodologies and reporting styles that are commonly used in the aviation market
- analysis, discovery, and outcomes of research on European passenger airlines
- general overview of sustainable aviation fuel (SAF)
- deep dive into the topic of SAF
- focus on other sustainability solutions for the passenger aviation industry.
Key Takeaway
- Passenger aviation is responsible for 2.5% of global GHG emissions
- Until 2040 there are no feasible solutions apart from carbon compensations and sustainable aviation fuel
- CORSIA regulations already cover all major European airlines
Warning of climate change
There are alarming pieces of evidence that thresholds have already been exceeded leading to irreversible changes in the ecosystems and climate system of our planet. One of the causes of climate change is the greenhouse effect that occurs as a result of increasing anthropogenic greenhouse gas (GHG) emissions into the atmosphere. By adding greenhouse gasses to the atmosphere, humanity further increases the absorption of infrared waves which leads to an increase in temperature at the Earth’s surface. While at pre-industrial levels, global atmospheric dioxide was around 280 parts per million (ppm); nowadays it amounts to as high as 422 ppm. The EU is responsible for about 18% of global CO2 emissions.
The passenger aviation industry is responsible for 2.5% of GHG emissions
The total EU GHG emissions amounted to about 4 Gt at pre-COVID levels. Of these emissions, around 22%, were attributed to the transportation sector.
Most emissions in the sector come from road transportation (80%), with aviation accounting for around 16%.
The aviation emissions are split up into passenger (85%) and cargo flights (15%). That means passenger flights make up around 130 Mt of CO2e emissions a year while cargo flights are responsible for approximately 20 Mt of CO2e. We concluded that an average domestic flight of less than 700 km emits 297 g of CO2 per passenger kilometer (pkm), accounting for both economy and business classes. (Sources: Eurostat, Statista, ICCT, IEA, FlyGRN, and Our World in Data)
On a global level, the aviation industry is expected to grow over the next decades. Annual growth rates are expected at 3.9% until 2040. According to Airbus, they could even reach 4.3% in the coming two decades. Subsequently, if no counteraction is taken, CO2 emissions will increase accordingly: meanwhile, EU aviation emissions are expected to grow by ~70% by 2030. By 2050, emissions could even grow by ~300%.
The aviation industry is known to be a sector in which the reduction of GHG emissions is particularly challenging. Unlike other subsectors, e.g., automotive where the shift to emission-free alternatives seems feasible by 2040, aviation is deemed exceedingly difficult to be decarbonized due to several factors including:
- Long innovation cycles
- Lack of alternatives to kerosene that offer similar energy-density
- Soaring prices for sustainable fuels
Technological enhancements are currently being developed, but scalability is out of reach before 2035. The current renewable energy supply does not suffice to power aircraft engines with green hydrogen just yet, and electrification of airplanes is even less feasible in the short to medium term. Therefore, it is not yet possible to completely abandon combustion engines. In total, jet fuel consumption in 2019 was 92 billion gallons. Meanwhile, fuel production efficiency for green hydrogen is relatively low at just 30%, especially compared to jet fuel production efficiency which is around 50%. Moreover, the total capacity of installed electrolyzers for green hydrogen production will reach 1.3 GW by the end of this year. It is expected to grow substantially to about 105 GW by 2031, but cannot be conceived as a viable option as of now. Additionally, the efficiency of hydrogen fuel cells is only around 60%, while a modern combustion engine aircraft has an efficiency of up to 96–99% (e.g. Airbus A321neo and Boeing 737 MAX 9). By 2035, Airbus hopes to develop the world’s first emission-free airliner. The British government also expects that they will be able to create such an aircraft by then.
As of today, the most effective measure to reduce emissions is Sustainable Aviation Fuel (SAF). SAF has the potential to reduce a majority of emissions within the aviation industry, however other measures must be taken to reduce the remaining emissions. Provided that sectoral emission reductions have been fully exhausted, remaining emissions should be mitigated via offset investment through an internationally trusted mechanism
Some large airlines (British Airways, Delta Airlines, United Airlines Holding, and others) have set out to achieve climate neutrality by the halfway point of the century. In 2021, the International Air Transport Association (IATA), constituted by the world’s leading airlines, aims to achieve carbon neutrality by 2050 to fight the climate crisis and formally requires air carriers to reduce greenhouse gas emissions.
CORSIA: ICAO’s international response to fighting climate change
As a response to the climate-oriented goals made during the Kyoto Protocol and Paris Agreement, the International Civil Aviation Organization (ICAO) agreed to provide a clear guarantee for the formation of a new Carbon Offset and Reduction Scheme for International Aviation (CORSIA). CORSIA has been developed to address aviation CO2 emissions by introducing innovations in aircraft designs, propulsion systems, operating procedures, fuels, and more back in 2016. As a safeguard, CORSIA sets forth to use 2019 emissions as a baseline; the industry’s growth thereafter shall take place with zero additional emissions, and net balancing offsets against emissions. CORSIA was developed in 2016 and formally launched in 2019. The scheme has been implemented in a voluntary phase from 2021 to 2026. As of the start of the pilot phase covering the years 2021 to 2023, 101 states have volunteered for CORSIA compliance, covering 77% of international aviation activity and 76% of potential CO2 growth. In the subsequent first phase from 2024 to 2026, all airlines with headquarters in voluntary member states need to comply with compensation additional emissions compared to 2019 levels. Airline operators will offset based on the average CO2 growth of the sector. With the start of the mandatory phase in 2027, 107 states will be CORSIA compliant, covering 90% of international aviation activity. By 2030, offset obligations will shift to cover +20% of individual operator growth. In 2032, ICAO will review CORSIA and decide whether the second phase is to be concluded, extended, or improved after 2035. Offset obligations by then will have shifted to cover +70% of individual operator growth.
A few exemptions apply to CORSIA: This includes interstate flights, flights with a maximum take-off mass of less than 5,700 kg, flights with total CO2 emissions of less than 10,000 tonnes, as well as humanitarian, medical and firefighting operations. Moreover, various countries have reasonably been exempted by CORSIA. These are less developed countries, landlocked developing countries, small islands, countries, and finally countries with a low level of aviation activity.
To comply with CORSIA, airlines have started to source SAF at a large scale and implemented carbon compensation programs. Our findings will be presented in one of the upcoming issues.
Coming next → An overview of the various carbon calculation methodologies commonly used by passenger airlines. Don’t miss out!
I would like to thank Yury Erofeev, Moritz Hake, Antonia Adamik, Victoire Ferrari, Sophie Beier, our partners, and the remaining team at SQUAKE for the performed research and analysis.
