Flying is harmful to the climate because a lot of CO2 is released when kerosene is burned. One environmentally compatible solution could be to run aircraft on sustainably produced hydrogen in the future. To do this, suitable supply chains must be established. A joint project in which Hamburg University of Technology is involved is investigating what this might look like.
"Above the clouds, freedom must be boundless," sang singer-songwriter Reinhard Mey many years ago. In the meantime, flying has come to stand for high CO2 emissions. But researchers are doing a lot to make the aviation industry climate-neutral. One approach is to use green hydrogen as an energy carrier instead of fossil kerosene. However, current capacities to produce hydrogen are still low, and large amounts of electricity are needed for production. One solution to this problem could be to generate the electricity in offshore wind farms at sea. Green energy forms the basis for splitting water into its components oxygen and hydrogen. Only if the hydrogen is produced from renewable energy sources can its use contribute to climate protection. This is a promising approach, but one that poses major challenges for the aviation industry.
Over the next three years, the joint project "HyNEAT - Hydrogen Supply Networks' Evolution for Air Transport" will conduct research to plan the networks for supplying hydrogen at airports. The focus is on the cost-effective production and transport of green hydrogen, which is a volatile gas. This complicates the planning of delivery networks. For use in aviation, the hydrogen must be liquefied because it has a smaller volume in the liquid state. This requires it to be cooled to at least minus 250 degrees Celsius. There are currently only a few such liquefaction plants in Europe, including one in Leuna in Saxony-Anhalt. For transport and storage, the liquid hydrogen must also be well insulated, otherwise there is a risk that it will evaporate.
Models for the supply of green hydrogen
At TU Hamburg, Professor Christian Thies' Resilient and Sustainable Operations and Supply Chain Management Group is involved in the project and tasked with developing mathematical optimization models for the so-called "Hydrogen Supply Chain Network Design Problem". For this purpose, energy systems and demand are analyzed and individual components are modeled. Finally, the results will be combined and specific solution methods for the complex models will be developed with colleagues from mathematics. For example, they will calculate what sizes the pipelines through which the hydrogen is transported must have, or how many trucks must be used for the transport. "With the help of the knowledge gained, our working group creates various scenarios. We examine them and use them to derive recommendations for action for politics and industry on how to efficiently provide green hydrogen for aviation," says Prof. Thies. "Just as necessary as developing new propulsion systems and aircraft concepts is building the corresponding hydrogen infrastructure. The biggest challenge will be to arrive at competitive costs that enable the operation of new types of hydrogen-powered aircraft," continues the supply chain expert.
The project is looking at and investigating a total of three levels: The researchers are sounding out the global hydrogen potential for aviation. They are calculating whether they can be implemented in the European energy system, with the associated scope extending to Africa and the Middle East. And finally, they describe their findings down to the local level to see what a typical airport must look like.
The joint project is funded by the German Federal Ministry of Education and Research (BMBF) with around three million euros. Participants include Leibniz Universität Hannover, Technische Universität Braunschweig, Technische Universität Clausthal, Technische Universität München, Technische Universität Hamburg, and an industry advisory board whose members include Airbus, Deutsche Aircraft, Lufthansa, Linde, Siemens Energy and Hamburg Airport.
Further information
