After other net-zero projects failed, the aviation giant is now focusing on hybrid power.
Airbus will use small electric motors in its first hybrid aircraft to reduce carbon emissions using technology developed for automobiles.
The motors have already been tested on an experimental helicopter, which flew for the first time last year. This gives hope that they will be used in other types of aircraft.
Karim Mokaddem is the head of Airbus’s electrification. He said that the company’s approach in building a hybrid replacement for the A320, its best-selling jet, will be a model for all future models.
He said that the strategy would simplify the task for planemakers to scale up the electrification as they will only have to add or remove engines depending on the size and weight of the plane.
The deployment of smaller motors will help Airbus to build on the advances pioneered in the automotive industry’s move away from fossil fuels. This will allow Airbus to access larger volumes of hardware, without having to rely on suppliers who have developed bespoke technology for the aviation sector.
Mr Mokaddem stated: “When it’s time to buy batteries and other electrical parts, we’ll have to compete in a much larger market than we are today.
The beauty of a module approach is that it allows us to work with the auto sector while enjoying the benefits of mass production.
Batteries are not powerful enough to power large aircraft such as the 180 seater A320. This is Airbus’s competitor to the Boeing 737, and a mainstay on short-haul routes around the globe.
Airbus is developing concepts for planes which would use liquid hydrogen propellant in place of jet fuel. However, hybrid power is seen as an immediate way to reduce emissions.
The hybrid aircraft would have auxiliary batteries that would supplement the jet engines. These jet engines would still provide the majority of thrust. The electric motors will kick in when necessary, for example during descent while the engines are idling.
They would also power non-propulsion-related activities, such as taxiing at the airport.
Airbus initially considered using larger motors and battery packs, but after calculating the weight of such a plan, it decided against it. Instead, it has settled on a modest hybrid design which aims to cut fuel consumption on standard flights by around 5pc.
Airbus in the UK is working on a longer and thinner wing, as well as more efficient jet engines.
The changes will help the industry reach its goal of zero net CO2 emissions in 2050. However, high prices of kerosene and the lack of availability of sustainable aviation fuel are holding back airlines’ efforts to move away from it.
He said: “If you know that SAF will not be enough and be expensive, then we must increase the performance of your plane. This can only be achieved by introducing a new clean energy. The only clean energy we have at the moment is electricity.
Airbus’ experimental DisruptiveLab, which flew for the first time last year, is currently being used to test hybrid technology that could be suitable for future jets.
He said that while the A320 was previously described as an intermediate step towards a more efficient helicopter model, it could be combined with two or three motors to create a hybrid successor.
The executive said, “I can’t go too far into architecture but you should size it twice or three times.”
Airbus had to accept that battery technology is limited for high-powered aircraft when deciding on a hybrid strategy.
Mr Mokaddem stated: “In the automobile industry, the larger and more powerful battery, the better. Until it is a fully-electric car.
“But we’ve come to realize that you have to be frugal when sizing the battery in aviation. You would need a nuclear reactor inside an aircraft if you tried to electrify all the components. When the battery runs out, you’re flying around with a heavy weight.
The auto industry’s belief that passengers could evacuate in case of a fire caused by a battery is not applicable to aircraft flying at 38,000 feet.
Airbus’s journey towards electrification was not straightforward. It took it down some blind alleys, before it settled on a plan it calls “micro-hybridisation”.
In the E-Fan X demonstration, which was developed in collaboration with Rolls-Royce and BAE, one of four jet engines on a BAE 146 was replaced by a 2-megawatt motor that produced a colossal 3,000 volts. The project ended in 2020 after a three-year period.
Mr Mokaddem stated: “These limits are ones that we will never reach.” We learned a great deal, is the honest feedback. Was it something that would have been able to represent a real-life product? No.”
Airbus has now envisaged that an A320 would require “something on the order of magnitude of 800 volts and one megawatt,” he said.
EcoPulse is a project developed in collaboration with Safran, a jet engine manufacturer, that is currently testing a distributed propulsion system. This system may not be used on a production plane.
Mr Mokaddem spoke in the London offices of Airbus after presenting with a Renault executive during a conference on Urban Mobility.
He spent 14 years with Peugeot Citroen where he admitted to being sceptical of the potential of hybrid and electric vehicles when Renault introduced the groundbreaking Zoe model in the year 2005.
He said: “I used to say that this would never happen, because there was no charging ecosystem. The car was also too expensive. And people wouldn’t accept a range of 200 kilometers. Look at what’s happening now. The exact opposite is true.
“But it has taken a century for the automobile industry to reach where they are today. In 20 years, we expect to repeat the exercise. “That’s why we started discussing it with the auto industry.”
M. Mokaddem stated that even with this collaboration, the hybrid A320 will not be on the market before the middle of next decade. This is when a new battery generation with twice the energy density of today should be available.
Batteries must be solid-state, as lithium-ion modules contain a liquid electrolyte which can cause a fire. These batteries are currently being developed in China, Europe, and the US. However, they will not be available anytime soon, given the millions of dollars that have been spent on the existing gigawatt-sized factories.
M. Mokaddem stated that firms like Heart Aerospace, which develops much smaller hybrid and electrical aircraft, should help establish safety cases for the planes.
“Not everything is going to happen as we perceive it today,” he said. We need to learn.
“But when you see how technology is evolving, and realize that the same ecosystem can feed the automotive and aerospace industries, you’ve got to think, ‘wow! We’re writing a new story about the future of transport’.”
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