Global air traffic, which is likely to continue growing strongly in the future, is already making a significant contribution to global warming. This increases the need and urgency to develop viable ways of transforming air traffic toward greater climate compatibility. New fuels and propulsion concepts are therefore essential to make air traffic as climate-neutral as possible in the future.

Global aviation is by far the most energy-intensive form of transportation and a strong driver of anthropogenic global warming. Its share of global greenhouse gas emissions is currently 3.5%, which is roughly equivalent to the entire annual CO₂ emissions of Japan. In addition, contrails and condensation trails as well as emissions such as nitrogen oxides (NO_X), water vapor, soot, sulfate and other aerosol particles are the main contributors to the climate impact of aviation. Against this backdrop, technical innovations to make aviation more climate-friendly have a very important role to play. In addition to optimizing the steering of conventional aircraft in the air, this includes in particular sustainable fuels, such as so-called e-fuels based on green hydrogen, for example, as well as new propulsion concepts, but also new designs, for example, to take into account the requirements created by new propulsion concepts and sustainable fuels.

However, there is a great need for research, development and implementation, and there are still significant uncertainties as to how the climate protection goals in air transport can be achieved. Nevertheless, due to the long-term development cycles in air transport, the research and innovation policy course must be set today so that more climate-friendly air transport can be achieved in the next 30 years.

Objectives and approach

The investigation is to be carried out in a TA short study, which will provide a compact overview of the research and implementation status of major projects in the fields of fuels (e.g. e-fuel/power to liquid, hydrogen, biokerosene) and propulsion concepts (e.g. [hybrid]electric flying, batteries/fuel cells) as well as their respective climate impact. Challenges and requirements for aircraft design and materials research are outlined. In addition, knowledge gaps and research needs are to be identified, which still need to be specifically addressed in order to realise the climate goals of aviation. Likewise, potential challenges are to be considered, such as energy consumption, manufacturing costs, transport logistics, safety, competition with food production, fuel cell performance and new materials.

The project will be implemented in three steps: First, an overview of the main levers for decarbonisation will be developed. These include fuels and drive concepts, but also design and materials research. The focus is on the research and development projects relevant to German aviation. Then trends, drivers and barriers that play a role in the implementation of innovative and climate-friendly solutions are considered. Finally, the main political fields of action are presented.