Climate-compatible aviation

Regional aircraft concept with fuel cells
Since the beginning of 2020, 45 scientists from 20 DLR institutes have been working together on the EXACT project (Exploration of Electric Aircraft Concepts and Technologies) to develop new technology components for a climate-friendly commercial aircraft. Here you can see the 70-passenger Fuel Cell Electric Regional Aircraft 'D70-FC10' concept with 10 fuel cells and propulsion units in the 'pods' under the wings. Hydrogen is supplied centrally via two hydrogen tanks in the rear of the fuselage. The aircraft has a range of just under 2000 kilometres.
Image: 1/8, Credit:
DLR (CC BY-NC-ND 3.0)
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Electric flight – emission-free, with a new look and quieter
Electric flight combines several advantages; it is locally emission-free, quieter, and makes completely new mobility options possible.
Image: 2/8, Credit:
DLR (CC BY-NC-ND 3.0)
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Exhaust gas measurements during formation flight
Behind the DC-8, which is using biofuel, scientists on board the DLR Falcon measure the exhaust gas composition.
Image: 8/8, Credit:
NASA
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The objective has now been set in Germany and Europe, with the aim of achieving climate compatibility in the economy and society. This is how it is worded in the EU's 'Green Deal'. The consequences of climate change also compel us to strive towards climate-compatible aviation, as this sector is responsible for 3.5 percent of global warming. New technologies are needed to ensure global mobility in the future. With 25 institutes and facilities active in aeronautics research, DLR is driving this change forward with sustainable technologies for environmentally compatible air transport. Expertise from DLR's space, energy and transport research programmes is also playing an important role in this.

DLR's ultimate vision is zero-emission air transport. Achieving the climate targets that have been established will require a disruptive approach. Aircraft and air transport must be considered as a complete system. DLR is one of the few research institutions in the world with the capability to simultaneously equip aircraft with new propulsion systems, record their emissions and model the resulting climate impacts within the context of the global air transport system. This systems expertise places DLR in the role of architect. From fundamental research through to applications, DLR works in close coordination and collaboration with the aircraft industry and the air transport sector.

Efficient aircraft configurations with an optimised mix of propulsion technologies

In concrete terms, the energy requirement of new aircraft must be reduced by at least half by 2050. In order to meet this target, these will have to become significantly lighter and more aerodynamically efficient, in combination with the introduction of innovative flight control and sensor systems. Efficient aircraft configurations will require an intelligent mix of alternative propulsion system concepts. In future, small and regional aircraft will be able to take off using battery or hybrid-electric systems, while medium-haul aircraft will be capable of flying using direct hydrogen combustion or fuel cells. On long-haul routes, aircraft will use Sustainable Aviation Fuel (SAF) in combination with highly efficient turbines.

Climate-optimised flight routes offer important possibilities for savings, and these can be harnessed quickly and for all aircraft. This is especially important given that two-thirds of the climate impacts of air transport are due to non-carbon-dioxide effects. Contrails play a significant role in this. They occur in specific places and are thus a key area of focus for routing.

The digitalisation of air transport is an essential tool in this comprehensive transformation. Optimised flight routes rely on complex computer simulations. New aeronautics technologies will make their initial flights as digital twins on a computer before being tested in the real world. Many of them have to be researched from the fundamentals, tested in practice and finally certified. DLR is in prime position to do this, with its research aircraft, wind tunnels, propulsion demonstrators and supercomputers.

In 2020, DLR published the white paper 'Zero Emission Aviation' with the German Aerospace Industries Association. DLR is currently working on a Zero Emissions strategy for aeronautics research.

Background articles

Innovative engine systems are changing air transport

In order to address the challenges of environment-friendly and efficient air transport, researchers at the DLR Institute of Propulsion Technology are investigating and developing new engine technologies and propulsion concepts for aviation. Over recent years, aeronautics researchers have increasingly been focusing on new systems, such as electric propulsion systems.

December 20, 2021

Discussing climate-neutral flight

What would airborne mobility have to be like to radically reduce the emissions caused by air transport? The whole world is talking about hydrogen as a possible solution. However, flying with hydrogen not only requires completely new propulsion systems, but it will also have to be produced and transported to the airport. How can these changes be made while ensuring that air transport remains economically feasible? Climate researcher Katrin Dahlmann, aircraft propulsion engineer Jannik Häßy and renewable energy researcher Veatriki Papantoni gathered to discuss how low-emission air transport might be achieved.

From air taxis to regional jets

New companies are emerging in the Silicon Valley region and are already positioning themselves to address the potential market for urban air transport, hoping to help shape its future. In a White Paper published in October 2016, the transport network company Uber identified a number of problem areas in relation to approvals, technology, operations and infrastructure that could be direct obstacles to the introduction of urban air taxis. Electric flight could provide solutions to some of these problems.

Reducing the carbon footprint and climate impact of contrails

From today's perspective, synthetic liquid fuels represent the most realistically viable alternative to the kerosene conventionally used for energy-intensive long-haul flights. For medium-haul routes, sustainable aviation fuels (SAFs) constitute technology that can be made available relatively quickly. By comparison, alternative propulsion systems based on fuel cells and hydrogen will only become ready for use in the 2030s, and only for regional flights at first. It is also worth bearing in mind that over 75 percent of CO₂ emissions from aviation occur on routes over 1,500 km, making this an area of urgent concern for climate protection.

One-third CO₂ and two-thirds non-CO₂ effects

Global air traffic accounts for around 3.5 percent of anthropogenic global warming to date. Researchers are analysing all of the areas in which the aviation industry has contributed to climate change since its inception, including carbon dioxide (CO₂) and nitrogen oxide (NOx) emissions, and the effect of contrails and contrail cirrus clouds.