Airbus trials electric engines to power the future of flight

Airbus plans to use a series of small electric motors to power its first hybrid airliner as it bids to slash carbon emissions[1] by relying on technology developed for the car industry. Trials of the motors are already underway on an experimental helicopter that first flew last year, boosting hopes of rolling them out across other types of aircraft. Karim Mokaddem, the firm's head of electrification, told The Telegraph that Airbus's approach to building a hybrid successor to the best-selling A320 jet will form a blueprint for all other models.

The strategy will simplify the task of scaling up electrification, he said, as it will mean the planemaker will only need to add or remove motors depending on the size of a plane. Crucially, the deployment of smaller motors and batteries will also help Airbus build on advances pioneered by the automotive sector in its own shift away from fossil fuels[2]. That will help Airbus access higher volumes of the required hardware without relying on suppliers to develop bespoke technology solely for the aviation industry.

Mr Mokaddem said: "When it comes to batteries and electrical parts we will have to compete with a market that's much bigger than the one we're in today. "The beauty of a modular approach is that we can work with the automotive sector and enjoy the benefits of volume production." While all-electric propulsion may be practical for very small aircraft, batteries lack the energy required to power full-sized airliners such as the 180-seat A320, Airbus's rival to the Boeing 737 and a workhorse on short-haul flights around the world.

Airbus is working on concepts for planes that would use a liquid hydrogen propellant instead of jet fuel[3], but views hybrid power as a more immediate pathway toward reducing emissions. A hybrid airliner would use auxiliary batteries to supplement its traditional jet engines, which would continue to provide the bulk of the required thrust. Electric motors would kick in at certain times, such as when the engines were idling during descent.

They would also power non-propulsion-related activities, such as taxiing at the airport.

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Airbus originally looked at deploying much larger motors and batteries but changed tack after calculations showed the plan would add too much weight to be viable. It has instead settled on a more modest hybrid design that aims to reduce fuel consumption by about 5pc on a standard flight. That would be accompanied by savings from other technological advances, including more efficient jet engines and a longer, thinner wing that Airbus is developing in the UK.

Combined, the changes should help propel the industry toward a target of net zero CO2 emissions by 2050, Mr Mokaddem said, even as airlines' attempts to switch away from kerosene are held back by high prices and low availability of sustainable aviation fuel[4] (SAF). He said: "If we know that, ultimately, SAF won't be sufficient and will be costly, we need to increase the performance of the plane. That can only come from the introduction of a new, clean energy, and the only clean energy that we have today is electricity."

Mr Mokaddem said that hybrid technology suitable for future jets is already being trialled on Airbus's experimental DisruptiveLab helicopter, which first flew last year. While previously described as a stepping stone toward a more efficient helicopter, two or three motors from the model could be combined in a hybrid successor to the A320, he said. The executive said: "I cannot go too far into the architecture but the idea is that you size it up two or three times."

In settling on the hybrid strategy, Airbus has had to accept the limits of battery technology for high-powered aircraft. Mr Mokaddem said: "In the automotive industry, the bigger and more powerful the battery the better, until ultimately it becomes a fully electric car. "But we have come to realise that in aviation you need to size the battery with frugality.

If you try to electrify everything you need almost a nuclear plant inside the aircraft. And when that battery is empty you are flying around a huge weight." Neither are aircraft able to recover energy through braking like a hybrid car, while the auto industry's view that passengers can evacuate in the event of a battery fire is hardly transferable to those flying at 38,000 feet.

Airbus SE A320Airbus plans to fit numerous small electric engines to its A320 model in a bid to reduce the carbon intensity of traditional propulsionCredit: Matthieu Rondel/Bloomberg

Airbus's path towards electrification has not been straightforward, with some projects taking it down blind alleys before it settled on the plan for what it calls micro-hybridisation.

The company's E-Fan X demonstrator, developed with Rolls-Royce, saw one of four engines on a BAE 146 jet replaced with a 2-megawatt electric motor producing a colossal 3,000 volts. The project was wound up after three years in 2020. Mr Mokaddem said: "These are limits that we would never reach.

The honest feedback is, yes, we learned a lot. Was it something that could represent a real product? No."

Airbus now envisages that an A320 hybrid would require "something of an order of magnitude of one megawatt and 800 volts," he said. Another project, EcoPulse, developed with jet engine maker Safran, is flight testing a so-called distributed propulsion system that may not feature in a production aircraft.

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Mr Mokaddem, who joined Airbus in 2021, spoke at the firm's London offices after making a joint presentation with a Renault executive at a conference on urban mobility. Earlier in his career he spent 14 years at Peugeot Citroen, where he admits to having been sceptical about the potential for hybrid and electric cars when Renault unveiled the ground-breaking Zoe model in 2005.

He said: "I was among the people saying that it would never happen because the charging ecosystem wasn't there, the car was too expensive and people would never accept a 200-kilometre range. And look at what is happening today. It's the exact opposite.

"But it took a century of hesitation for the automotive industry to get to where they are now. We are expecting to do the same exercise in 20 years. That's why we have started to discuss it with the automotive industry."

Even with such collaboration, a hybrid A320 is unlikely to reach the market until the middle of the next decade, when a new generation of batteries with double today's energy density should be available, Mr Mokaddem said. The batteries must also be of a solid-state design since lithium-ion modules use a liquid electrolyte that poses a fire risk. While under development in China, Europe and the US, such batteries are unlikely to become available soon given the billions of dollars lavished on existing gigawatt factories.

Meanwhile, firms such as Heart Aerospace are developing much smaller hybrid and electric aircraft that should help establish the safety case for the planes, Mr Mokaddem said. He said: "Not everything will happen the way we see it today. And we need to learn from others.

"But when you look at how the technology is evolving and realise that the same ecosystem could feed the aerospace and automotive industries, you have to say, 'wow, we're writing a completely new story on the future of transportation'."

References

  1. ^ to slash carbon emissions (www.telegraph.co.uk)
  2. ^ shift away from fossil fuels (www.telegraph.co.uk)
  3. ^ instead of jet fuel (www.telegraph.co.uk)
  4. ^ low availability of sustainable aviation fuel (www.telegraph.co.uk)