Since 2020 TE has conducted assessments at the aircraft, airport and ATS level to prepare the 2nd Global Assessment. The final results are described in the following.
The present study shows that an ambition of -30% CO2 reduction (per seat-km) can be set at mission level for a next generation SMR aircraft that could enter service within the 2030 –
2035 timeframe. For a LR aircraft, with advanced evolutionary tube-and-wing technologies, a target of -20% (per seat-km) is more credible by 2035. NOX reductions of over -40% are
achievable as well, with remaining challenges for the smaller thrust class high bypass-ratio engines.
Clean sheet designs for regional turboprop aircraft show very promising results as well (of about -25% to -30%), relying on all new airframe, advanced aerodynamic technologies and
next generation large turboprop engines or small thrust-class open fans.
Noise reduction levels of -20% (corresponding roughly to -3dB) can be achieved in most cases, depending on engine architecture or aircraft configuration. This implies that the research
effort on noise is pursued in future frameworks and noise impact of decarbonization technologies is monitored and minimized. The high level of interdependencies between noise
and C02 could annihilate these potential noise reductions without further progress on these technologies.
The final impact of the Clean Sky 2 programme can be summarised as follows:
- in the no action scenario, where older aircraft are retired and continue to be replaced by state-of-the-art aircraft which recently entered into service or are about to enter service
(such as new generation families like A220, A320neo, A330neo, A350, ATR-72, Boeing 737MAX, 777-X, Embraer-E2, ...) total CO2 emissions of aviation would increase by 43%.
- if aircraft with Clean Sky 2 technologies were introduced as of 2035, this CO2 increase would be limited to 23%, a reduction of 14.5% in terms of CO2 levels in 2050.
- If aircraft with Clean Aviation technologies (only for Regional and SMR) were introduced as of 2035,
o carbon neutral growth of aviation could be ensured as of 2035 onwards if hydrogen propulsion is used, thanks to an additional 15% CO2 reduction.
o else, an additional 11% net carbon reduction could be ensured if only the regional and SMR aircraft were flying 100% SAF (assuming 80% carbon footprint for SAF on average).
The estimated aviation emissions in 2050 strongly depend on the type of aircraft which will enter into service as the next generation green aircraft but first and foremost on the fleet replacement rate which may be achieved. This study also shows that this process is slow, as it is also linked to production rates and other economic factors related to airlines, market uptake, policy initiatives, etc. Feet replacement rates of 75% by 2050 turn out to be ambitious (even in terms of RPK) and rather hint to 70%. A realistic fleet replacement rate in terms of a/c numbers would be around 60% by 2050.
The complete results of the 2nd assessment are published in the 2nd assessment report. Additional dissemination activities (e.g. conference participations) are additionally forseen to make the public aware of the results.
