The big picture of emissions accounting for future aircraft propulsion systems

Videoconference, 14 February 2024 — The 23rd edition of the monthly familiarisation webinar on basic knowledge on aviation and the environment focused on the task of estimating life-cycle emissions for both future aircraft propulsion systems and conventional gas turbine propulsion systems using sustainable aviation fuels (SAF).

The session highlighted the pivotal role of these assessments in seeking to reduce fossil CO2 emissions in aviation.

Theo Rindlisbacher, physicist and scientific advisor on emissions, air quality and climate at the Swiss Federal Office of Civil Aviation (FOCA), was the invited speaker. Drawing over 80 participants, the webinar facilitated a robust exchange of questions and insights between the audience and the presenter.

A key takeaway emerging from the discussions was that emission performance comparisons between different propulsion solutions are complex and intricately linked to the life-cycle greenhouse gas (GHG) emissions intensity of electricity, which in many European countries is very high.

Mr Rindlisbacher shared the findings of a simplified assessment conducted by FOCA, which revealed that for all propulsion alternatives, the primary energy demand approximately doubles in comparison to the energy content of fossil fuels. This increase encompasses the energy requirements for extraction, refinery, transport and storage.

In the second part of the webinar, Mr Rindlisbacher shared his first-hand insights gleaned from practical engagement with electric flight technologies, drawing from his experience representing FOCA in the testing of the Pipistrel Velis Electro aircraft specifications.