European plane manufacturer Airbus has unveiled a concept called ZEROe for three possible aircraft types that run on a mixture of hydrogen combustion and H2-powered fuel cells, with the goal to bring at least one zero-emission commercial airplane to the market by 2035.
One of the models unveiled looks similar to a classic commercial aircraft, except with longer, more flexible wings. Another resembles a turboprop-powered airliner with its arrangement of six-bladed propellers. And the third is a “blended-wing body”, a revolutionary design that Airbus claims has seen some traction among engineers over the last year.
“As recently as five years ago, hydrogen propulsion wasn’t even on our radar as a viable emission-reduction technology pathway,” said Glenn Llewellyn, Airbus vice president for zero-emission aircraft.
“But convincing data from other transport industries quickly changed all that. Today, we’re excited by the incredible potential hydrogen offers aviation in terms of disruptive emissions reduction.”
Air travel is responsible for 2% of worldwide carbon emissions, but aviation is a sector considered difficult to decarbonise. Batteries for larger electronic planes would be too heavy if current battery technology is used, while non-fossil synthetic fuels or green hydrogen are still very expensive.
French energy group Engie and European aerospace joint venture Ariane Group – in which Airbus owns a 50% stake – earlier this month had already signed a cooperation agreement on renewable liquid hydrogen to speed up the decarbonisation of heavy transport and airplanes.
Airbus estimates hydrogen has the potential to reduce CO2 emissions in aviation by up to 50%.
The ZEROe concept aircraft would be powered by modified gas-turbine engines that burn liquid hydrogen as fuel. At the same time, they also use hydrogen fuel cells to create electrical power that complements the gas turbine, resulting in a highly efficient hybrid-electric propulsion system, the manufacturer explained.
“Hydrogen has a different volumetric energy density than jet fuel so we have to study other storage options and aircraft architectures than existing ones,” said Jean-Brice Dumont, Airbus EVP Engineering.
“This means the visual appearance of our future zero-emission aircraft will change. These three configurations provide us with some exciting options for further exploration.”
Each of the three options Airbus has unveiled have a slightly different approach to integrating the liquid hydrogen storage and distribution system:
- In the Turbofan model two hybrid turbofan engines provide thrust. The liquid hydrogen storage and distribution system is located behind the rear pressure bulkhead.
- In the Turboprop model, a liquid hydrogen storage and distribution system is located behind the rear pressure bulkhead. However, two hybrid hydrogen turboprop engines, which drive the six-bladed propellers, provide thrust.
- The the Blended-Wing Body (BWB) model features an exceptionally wide interior, thereby opening up multiple options for hydrogen storage and distribution. Liquid hydrogen storage tanks could be stored underneath the wings. Like the turbofan aircraft, two hybrid hydrogen turbofan engines provide thrust.
Airbus expects a zero-emission commercial aircraft to roll off its assembly lines for entry into service by 2035, if hydrogen technology development progresses at the expected rate.
According to its plan, the plane maker will need to launch the ZEROe aircraft programme by 2025. That gives the company’s engineers about five years to mature all the required hydrogen technologies.
Over the coming months, several hydrogen demonstrator programmes, which will test hydrogen fuel cell and hydrogen combustion technologies respectively, are estimated to be formally launched. A full-scale aircraft prototype is estimated to arrive by the late 2020s.
“The ZEROe will be the world’s first zero-emission commercial aircraft,” says Jean-Brice. “As an engineer, I can’t think of working on anything more exciting than that.”