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However, he warned that “the transition to hydrogen, as the pri- tanks prepared at Airbus facilities in France
mary power source for these concept planes, will require decisive and Germany.
action from the entire aviation ecosystem. Together with the
support from government and industrial partners, we can rise Airbus will define the hydrogen propulsion
up to this challenge to scale-up renewable energy and hydrogen system requirements, oversee flight testing,
for the sustainable future of the aviation industry.” and provide the A380 platform to test the
hydrogen combustion engine in cruise phase
while CFM International will modify the com-
Stepping Up Efforts bustor, fuel system, and control system of a
Airbus said that in order to tackle these challenges, airports will GE turbofan engine to run on hydrogen.
require significant hydrogen transport and refuelling infrastruc- It will be mounted along the rear fuselage of
ture to meet the needs of day-to-day operations. Support from the flying testbed to allow engine emissions,
governments will be key to meet these ambitious objectives with including contrails, to be monitored sepa-
increased funding for research and technology, digitalisation, rately from those of the engines powering
and mechanisms that encourage the use of sustainable fuels the aircraft. CFM will execute an extensive
and the renewal of aircraft fleets to allow airlines to retire older, ground test programme ahead of the A380
less environmentally friendly aircraft earlier. flight test.

In 2021 Airbus announced that it was stepping up efforts to According to Airbus VP Zero-Emissions, Glenn
build hydrogen tanks for the next generation of aircraft by cre- Llewellyn, authoring a chapter in ICAO’s
ating Zero-Emission Development Centres (ZEDC) at its sites in Environmental Report “a down selection
Bremen (Germany) and in Nantes (France). The aim of ZEDC is on ZEROe’s technology choices and aircraft
to achieve cost-competitive cryogenic tank manufacturing to configurations is expected to start as early
support the successful future market launch of ZEROe (Zero as 2025, which means that the first hydro-
Emissions Aircraft) and to accelerate the development of hydro- gen-powered airliner
gen-propulsion technologies.
could be certified and ready for service entry
The technology developments will cover the full product and by 2035.” He adds that “while liquid hydrogen
industrial capabilities from elementary parts, assembly, systems has a specific energy-per-unit mass which is
integration and the cryogenic testing of the final liquid hydrogen three-times higher than traditional Jet-A1 ker-
(LH2) tank system. osene, its volumetric energy density is much

Both ZEDCs will be fully operational in 2023 to build LH2 tanks lower, therefore, the visual appearance of
with a first flight test scheduled for 2025. The tank is a safety-crit- future aircraft will likely need to adapt accord-
ical component, for which specific systems engineering is needed ingly – with more internal volume
because LH2 needs to be stored at -253°C to liquefy, which is devoted to storing the liquid hydrogen.
needed for increased density.
“This is reflected in the respective ZEROe
And the challenge for commercial aviation, is to develop a com- concept configurations whereby, in the tur-
ponent that can withstand repeated thermal and pressure cycling boprop and twinjet designs for example, extra
which an aircraft application demands. fuselage length is devoted to storing liquid

Separately, Airbus and CFM International are collaborating on a hydrogen in cylindrical tanks. Meanwhile, the
hydrogen demonstration programme that will take flight around largest concept aircraft takes advantage of its
the middle of this decade using an A380. The demonstration exceptionally large internal volume afforded
will use an A380 flying testbed equipped with liquid hydrogen by the “blended-wing” itself for accommodat-
ing the hydrogen.”

Airbus is working on several different hydro-
gen power approaches, Llewellyn explains,
which include ‘direct hydrogen combustion’
and ‘hydrogen fuel cells’.

“The latter, which produce zero emissions,
convert energy stored in hydrogen atoms into
electrical power via an electro-chemical reac-
tion. Hydrogen is also a key ingredient for a
third category: power-to-liquid synthetic fuel
which is even compatible with existing aircraft
– whereby ‘green’ hydrogen is combined with
carbon dioxide to form a synthetic fuel with

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