Benefits and challenges of liquid hydrogen fuels in commercial aviation

Abstract

This paper aims to highlight the opportunities and challenges associated with the adoption of hydrogen fuels in aviation. An overview of the environmental and economic benefits and technological challenges is presented. A simplified model is subsequently introduced to estimate the benefits of liquid hydrogen fuels in aircraft of conventional configurations, encompassing changes in volume, weights and environmental impacts. This paper concludes that hydrogen in cryogenic liquid form demonstrates great potential to become a highly sustainable commercial aviation fuel with lower emissions and less fuel mass for a given range, resulting in better economies. The presented numerical case study highlights that despite the worsened aerodynamic and structural characteristics, a take-off weight saving of more than 11% (small regional jet) and up to 25% (large wide-body aircraft) can be achieved when considering a liquid hydrogen retrofit of current generation jetliners. Unfortunately, the volume required by integral tanks prevents the translation of this weight saving in additional payload, but remarkable economic savings can be obtained. However, the implementation of this technology comes with many technical challenges, including the development of sustainable production, storage and delivery systems that shall not dilute the environmental benefits as well as widespread uptake to ensure financial sustainability.