(Cologne) – The German Aerospace Center (DLR) is developing an aviation strategy for emission-free flying. The research goal is to develop highly efficient, climate-friendly aircraft. These should take off with climate-friendly drive concepts and sustainable fuels that match their range and size. One looks at aircraft and air traffic as an overall system. 
“DLR’s vision is emission-free aviation. Getting there requires a disruptive approach and new technologies,” the company explained. The need for research and development is considerable, said DLR CEO Anke Kaysser-Pyzalla. “The energy requirements of future aircraft must be reduced to at least half by 2050. “This requires technologies to reduce aerodynamic resistance and overall weight together with innovative flight control and sensors,” says Markus Fischer, Head of Aviation at DLR. In addition, an “intelligent mix of alternative drive concepts” is required.
Long-haul flights with sustainably produced kerosene
On short to long-haul routes, turbofan engines powered by regeneratively produced kerosene enabled largely climate-neutral operation. To achieve this, the existing fleet and the existing infrastructure only need to be modified minimally. According to DLR, “Sustainable Aviation Fuels” (SAF) “significantly reduce the carbon footprint and also reduce the climate impact of contrails.”
Medium-haul with direct hydrogen combustion
In the medium term, the use of hydrogen is particularly suitable for regional and short-haul aircraft. The energy source reduces local CO2 emissions in aviation to zero.
“Towards emission-free aviation”, free as a PDF (21 pages)
“Research into safe and reliable hydrogen combustion” and the handling of the energy source should “prepare its commercial applicability in aircraft over the next five years”.
Short journeys with fuel cells
Despite their very high levels of efficiency, both batteries and fuel cells are “only suitable for small aircraft and regional aircraft in the foreseeable future”. Research into high-performance electric motors, batteries and fuel cells is necessary. “Then a decision can then be made in the next five years about medium-term application in commercial aircraft.” The DLR sees further key research priorities in the “complex overall system from aircraft design, production, operation on the ground and in the air to maintenance.”
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DLR develops strategy for emission-free aviation. © DLR (CC BY-NC-ND 3.0)
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Flying with fuel cells: In September 2016, the hydrogen fuel cell aircraft “Hy4” flew over Stuttgart Airport. © DLR (CC BY-NC-ND 3.0)
