The energy transition in air transport, with the goal of zero emissions, is possible by mid-century but requires a considerable increase in innovation. This is being emphasised by the German Aerospace Center (Deutsche Zentrum für Luft- und Raumfahrt; DLR) and the German Aerospace Industries Association (Bundesverband der Deutschen Luft- und Raumfahrtindustrie; BDLI) at today's joint presentation of the white paper ‘Zero Emission Aviation – Emissionsfreies Fliegen' to the Federal Ministry for Economic Affairs and Energy (Bundesministerium für Wirtschaft und Energie; BMWi). For the first time, the paper comprehensively summarises the current state of research and technological fields of action on the way to zero-emission flying in all areas of air transport. This will require a diverse technology mix, with extensive developments in the areas of sustainable fuels, new configurations, battery and fuel cell technology, as well as various hybrid propulsion solutions and new gas turbine concepts. The transformation to zero-emission air transport by 2050 requires close cooperation between science, industry, and governments.
"The time has come to start a new chapter in aviation. Our white paper shows the path to emission-free flying for the 'Green Deal' in aviation, which will lead to new technologies, attractive high-tech jobs, fascinating products and the promotion of social prosperity in Germany and Europe," says Rolf Henke, the member of the DLR Executive Board responsible for aeronautics research and technology. "With the transformation of an entire industry, however, this path also involves major research efforts. In particular, flying demonstrators will be an essential element in the areas of electric flight, hydrogen, new fuels and new aircraft configurations."
Reiner Winkler, BDLI's Vice President for Aviation emphasises: "We are currently facing two unprecedented challenges. On the one hand, the coronavirus pandemic has triggered the most severe economic crisis in our industry. The collapse of global air traffic creates a dramatic situation for manufacturers as well as for our deeply rooted supply chain, which is located throughout Germany. On the other hand, aviation is on the threshold of climate-neutral flight. We have set ambitious goals for ourselves; by 2050 we will achieve climate-neutral flight. That is why up to 90 percent of our investments in research and development have long been directed at reducing emissions."
Considering the current situation of a massive economic crisis and maximum technological challenges, this white paper is a first step towards disruptive technologies. At the same time, it reinforces the proven path of cooperation between industry and aeronautics-oriented large-scale research. The aircraft of the future should be both climate-neutral and competitive, and they should be built in Germany and Europe. The white paper will be a valuable basis for enhancing the cooperation between research, industry, and government to strengthen climate protection and Germany as a business location together with the 'energy transition in the skies'.
Extensive new technologies
Zero-emission aviation requires a great deal of research. To achieve this goal, several radical technologies need to be studied in parallel and their use evaluated in relation to the size and range of aircraft. In the field of urban air mobility and regional aircraft for short journeys within densely populated areas, battery-electric concepts are promising, while aircraft with hybrid propulsion concepts based on fuel cells are likely to replace today's aircraft on short and medium-haul flights. Sustainable fuels, in combination with new gas turbine concepts, have great potential for emission reductions on medium and long-haul flights. The use of directly burned green hydrogen in particular is becoming a long-term focus. The use of turbo-hybrid electric propulsion concepts and even fuel cells is also conceivable for long-haul flights. New aircraft configurations offer the possibility of integrating new propulsion technologies in a particularly efficient way.
The successful introduction of key technologies for climate-friendly air transport requires extensive flight tests and thus a scheduled demonstrator programme. Until the global aircraft fleet is replaced by the next generation in around 20 to 30 years, financial resources will be needed to improve the climate impact of current aircraft, in addition to investments in new technologies. New operational measures such as the implementation of climate-friendly routing could, for example, be applied quickly to a substantial part of the fleet. Studies by DLR show that even small changes in flight guidance with an increase in operating costs of only one percent could lead to a reduction in climate impact of up to 10 percent.