Hydrogen, the energy vector for the plane of tomorrow

This contamination free technology has taken a crucial role in the development of modern aeronautics and the present objective is the realization of fully electrical planes. Hydrogen fuel cells are currently being tested as propulsion system in Unmanned Aerial Vehicles by companies like Boeing, where all the advantages it could offer are being taken into consideration, from its efficiency to the possibility to recycle the water generated as by-product, maybe for use in the plane’s toilets.

The application of this technology as propulsion for large commercial planes is far fetched, since at present time, fuel cells do not provide enough energy, but this technology could be implemented as an auxiliary power unit (APUs) that could start the engines in the plane, power the air conditioning, the lights, cabin pressure… etc.

The European project “power optimised aircraft” aims to further develop fuel cell technology applied to high efficiency APUs. This project involves several European private companies and different public organisms from different countries. Spain is represented by the Instituto Nacional de Técnica Aeroespacial (INTA), CESA SA. and SENER SA.

There are different approaches towards how the hydrogen needed to fuel the cells is to be obtained. To this date, most experimental designs include high pressure storage tanks for the hydrogen, but this presents serious risks. It would call for changes to the plane designs and refuelling logistics, all added to the fact that the light density of hydrogen implies a fast consumption rate that would only allow for short flights. All these inconveniences have favoured the study of other sources of hydrogen, such as its on board production from kerosene already present in the plane as engine fuel, therefore eliminating the need for any major modification.

Two different procedures to reform the kerosene into hydrogen are being studied; one involving preparing the kerosene by a previous process to obtain richer hydrogen flow. And the second option would be a fuel cell capable of transforming the hydrocarbon directly into electric energy.

This new system would be lighter and more compact, reducing the weight of the equipment, but the technology to achieve this is currently at the evaluation phase.

Aware of the repercussion of this new technology in the aerospace sector, the Círculo de Innovación de Materiales, Tecnología Aerospacial y Nanotecnología (CIMTAN) (Innovation Circle in Materials, Aerospace Technology and Nanotechnology) is producing a report on the subject to be released at the end of the year. Its aim is to offer an overview of the technology and set the trends and roadmap that the scientific community is following.