Do Fuel Cells Have a Future in Aviation?

Yes, they almost certainly will. The image above is the first practical hydrogen-electric, zero-emissions aviation solution. ZeroAvia's novel hydrogen-electric powertrain replaces traditional engines on existing fixed wing aircraft, simplifying regulatory issues and reducing time to market. Just look at what ZeroAvia is doing:?https://www.zeroavia.com/

Quite impressive, isn’t it?

They say “Zero-emission aviation starts with?green hydrogen“. We couldn’t agree more. If the hydrogen is not generated in a sustainable way, all our efforts could be in vain.

You may argue, that green hydrogen is very expensive. That is true for today. But it will change. With more demand and large scale production, the price will come down.

So, why are fuel cells not even mentioned in our 5-step-plan. The short answer would be they are?not yet?in our plan. Here are the details:

We are starting with a training aircraft. The idea is to give airlines a financially easy entry into the green aviation world. A training aircraft is a light aircraft. In our case, a two-seater for a flight student and the instructor. When it comes to very light aircraft, the fuel cell does not work so well. While the electric motor is really light, even including the controller, a fuel cell is quite heavy for this category of aircraft. Also, the storage of hydrogen on board is heavy. We are going for solid state storage. High pressure or super-cooled tanks would be even worse. We can accommodate the weight of the solid state storage but an additional fuel cell would be too much. That is why we concentrate on burning the hydrogen in a combustion engine, preferably a rotary.

Photo: Horizon Fuel Cell Technologies

When it comes to mid-size commuter airplanes, the situation is different. There is the room and weight capacity to have high pressure (or super-cooled) hydrogen tanks on board and one or more fuel cells. In this environment it can make a lot of sense to use fuel cells. When it comes to large passenger aircraft – as used on intercontinental flights – it seems, from today’s point of view, that fuel cells will not work. On the other hand, large aircraft turbines can run very well on hydrogen. Only modest modifications are needed. All the large jet engine manufacturers are working on solutions. This is a video by General Electric’s?GE Aviaton:?https://www.youtube.com/watch?v=GRxzmOYaFhY

So, from our current point of view, the ideal use for hydrogen electric powertrains will be in mid-size commuter planes covering mid-range destinations. In smaller planes, it might be more desirable to store hydrogen in solid state and burn it in a combustion engine. This might give the rotary engine a new lease on life. All the well known disadvantages of the rotary engine will disappear as soon as hydrogen is used as fuel.

In large airliners for long distance travel, it looks like there is room for super cooled storage of hydrogen. And large turbofan engines will be able to run efficiently and perfectly clean on hydrogen. But it has to be green hydrogen!

Back to our own applications: Yes, there will be fuel cells in our future. For now, we see them mostly in our infrastructure development. Imagine, a flight school typically has one or more hangars. Hangars have roofs. Nowadays, these roof are almost always empty. They could be stacked with photovoltaic panels. A flight school could generate some of the electric power they need on their own roof. This power could be used to charge batteries. But it could also be used to generate hydrogen from water by electrolytic conversion. This would be perfectly green hydrogen and could be used for airplanes.

We can also imagine charging trailers for electric aircraft which would use hydrogen (stored in solid state) to drive a fuel cell for battery charging.

It is too early to tell where all these developments will go. However, it is not to early to start the process. We are just at the beginning of a long road ahead.