States and Prospects of Hydrogen Storage Technologies in Aircraft Applications

Abstract: In recent years, more than 100 000 commercial flights have departed daily, and the number of passengers worldwide are expected to double within the next two decades, assuming there are no long-term impacts of the Covid-19 pandemic. Meanwhile, the aviation industry will need to undergo a shift to more sustainable fuels, due to the growing issue of climate change and implementation of policies that regulate the use of fossil-based fuels such as kerosene. Hydrogen has been established as one proposed fuel for aviation, due to its properties of high energy contents and the main emissions being water vapor. For hydrogen to be used as an aviation fuel, there is a need for efficient, safe and low-cost storage systems. Based on a set of quantifiable parameters the report aims to, based on technical, economical and safety perspectives as well as conclusions from previous studies, identify and quantify the current states and prospects of some of the most promising methods and technologies for hydrogen storage in commercial aircrafts. Furthermore, other important parameters are being identified and discussed after analyzing the viability of several physical and material storage technologies. The results show that although none of the technologies are sufficiently developed and ready for aircraft applications, cryogenic liquid hydrogen storage offers the best opportunities for the near future. Other forms of physical storage show some promise, whereas some material storage methods have large theoretical potential but require rapid development. While the other studied systems can’t be dismissed, a lot of research and development would have to be successful in order to reach technological and commercial viability. Further research is necessary for quantifying storage costs as well as prospects and targets for costs and gravimetric energy densities. All things considered, it is concluded that for hydrogen to be viable as an aviation fuel, hydrogen storage systems need to perform on a level much higher than today.