Airbus - ZEROe - Hydrogen propulsion

Hydrogen propulsion – is emission-free flying within reach?

Jennifer Weitbrecht
08.12.2020
5 minutes

The future of aviation is more uncertain than ever before, but it is clear that a lot things have to change! Today, however, our article does not focus on Covid-19-based measures, but on other topics that will keep us busy for a long time to come: climate change and zero-emission flying with hydrogen propulsion.

Is hydrogen propulsion the solution?

The demands are high: to fly cleanly, if possible without any emissions. This causes headaches. But it is not for nothing that the aviation industry is considered particularly innovative! Airbus has set itself the ambitious goal of “decarbonising the aviation industry”. The company wants to be the first manufacturer to operate an emission-free aircraft.

Intensive research is being carried out on three concepts for emission-free flying, all of which are hydrogen-powered, none of which are battery-powered. The three models were already unveiled in September this year:

This is a historic moment for the commercial aviation sector as a whole and we intend to play a leading role in the most important transition this industry has ever seen. The concepts we unveil today offer the world a glimpse of our ambition to drive a bold vision for the future of zero-emission flight.

Guillaume Faury – Airbus CEO

Airbus emphasises that hydrogen is a clean fuel, which is “extremely promising and probably a solution for aerospace and many other industries”.

I strongly believe that the use of hydrogen – both in synthetic fuels and as a primary power source for commercial aircraft – has the potential to significantly reduce aviation’s climate impact.

Guillaume Faury – Airbus CEO

According to the company’s own statements, each of the three models could be put into operation by 2035. What sounds like a long period of time will pass by in a flash, given the long development cycles and test phases of aircraft development.

Three concepts – one common ground

Although their external construction is very different, the concepts rely on different technologies and aerodynamic configurations. However, they all have hydrogen as their primary energy source in common and are codenamed ZEROe. A promising name for what may be the first climate-neutral and emission-free commercial aircraft.

It remains to be seen which of these concepts will ultimately prevail and possibly replace conventional models. However, in order to make a commissioning by 2035 possible, the selected programme would have to be launched no later than 2028.

ZEROe - Airbus - emission-free flying

ZEROe concept number 1 – Turbofan design

This commercial aircraft looks rather conventional and is being developed for a range of 3,700 kilometres. It should be capable of transcontinental operation.

PassengersUp to 200 passengers
Range3,700 kilometres
PropulsionTwo modified, hydrogen-fired turbofans. Tanks for liquid hydrogen behind the rear pressure bulkhead.

ZEROe concept number 2 – turboprop design

Concept number 2 is also a model similar to conventional aircraft, but smaller than the turbofan variant and intended for short-haul flights.

PassengersUp to 100 passengers
Range2,00 kilometres
PropulsionTurboprop engines driven by hydrogen combustion

ZEROe concept number 3 – Blended-wing-body

In this particularly futuristic aircraft form, known as the “Maveric“, the wings merge with the main body of the aircraft (like KLM’s Flying-V).

PassengersUp to 200 passengers
Range3,700 kilometres
PropulsionTwo modified, hydrogen-fired turbofans. Tanks for liquid hydrogen behind the rear pressure bulkhead.

Flying emission-free until 2035 – how realistic is that?

Airbus’ three new concepts are expected to be a milestone in the aviation industry’s journey towards the first climate-neutral, zero-emission commercial aircraft. However, meeting the tight timetable does not only depend on Airbus.

The transition to hydrogen, as the primary power source for these concept planes, will require decisive action from the entire aviation ecosystem.

Guillaume Faury – Airbus CEO

Support and guidance from governments and industry partners are crucial factors for success. But can we really afford to delay the future of clean technologies any longer? A resounding no! Nevertheless, the question remains to what extent the planned implementation is feasible at all.

Turbine manufacturers in particular bear the main burden of the technological development of an unusual aircraft type, especially in the case of the blended-wing design. Even without this additional challenge, it cannot be taken for granted that the existing kerosene-absorbing engines can be converted in such a short time to consume hydrogen instead.

At the beginning of the year, the leading turbine manufacturer MTU estimated that revolutionary concepts for flying could not be expected before 2040. One of the reasons given was the still very expensive production of biofuel.

Hydrogen storage within the ZEROes

One of the biggest challenges of hydrogen propulsion is the storage of hydrogen, which, unlike kerosene, cannot be stored in wing tanks.

Hydrogen in its liquid state has a volume four times larger than kerosene. Therefore, strong compression is necessary to achieve an acceptable flight distance with hydrogen technology. This compression can be achieved with spherical or cylindrical tanks. In addition, cooling to minus 253 degrees Celsius is absolutely necessary to maintain the liquid aggregate state.

To solve the storage problem and provide sufficient space for passengers, Airbus plans to move all fuel tanks in the two “conventional” designs to the rear fuselage section. A closer look reveals that the rear section of the fuselage will therefore have no windows. In contrast to the conventional design, the blended-wing-body concept offers significantly more scope for hydrogen storage and distribution.

How environmentally friendly is flying with hydrogen propulsion in reality?

Hydrogen is regarded as an important component of a climate-friendly energy supply, as its use does not produce any greenhouse gases, however a great deal of energy is required for its production.

A decisive factor for the ecological balance of hydrogen is not least the origin of electricity used to split water into hydrogen and oxygen. Only if this electricity is produced with no or only minimal greenhouse gas emissions does the life cycle assessment really turn out to be positive. If, however, the production of hydrogen already produces those pollutants that could be saved in the air, everything would be a sham…

Hydrogen propulsion – how does it work?

Hydrogen as a primary energy source is a source of hope for many branches of industry in order to achieve climate-neutral targets. Soon you can read on WingMag how this pioneering technology works.

by Jennifer Weitbrecht

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