EasyJet designs new green aircraft taxiing system based on zero-emissions hydrogen fuel cell technology
Mon 8 Feb 2016 – Low-cost carrier easyJet is to develop and trial an onboard hydrogen fuel system that would enable it to be used for zero-emissions aircraft taxiing operations. The hybrid plane concept utilises a hydrogen fuel cell stowed in the aircraft’s hold and the system allows energy to be captured as the aircraft brakes on landing, which is then used to charge lightweight batteries when the aircraft is on the ground. The airline says ground taxiing is responsible for around 4% of its total annual fuel consumption due to its high frequency, short sector length operations. Following ideas from Cranfield University students on what air travel may look like in the future, the concept has been designed by easyJet’s engineering team, which will now work with industry partners and suppliers towards setting a trial to take place later this year.
The inspiration for the concept draws on the Kinetic Energy Recovery System (KERS) found in Formula 1 cars, explains the airline. Each aircraft would have motors in their main wheels, and electronics and system controllers would give pilots control of the aircraft’s speed, direction and braking during taxi operations. This would reduce, if not remove altogether, the need for tugs to manoeuvre aircraft in and out of stands, so delivering more efficient turnaround times and increased on-time performance.
The airline points out that its aircraft average 20 minutes of taxi time per flight and equivalent to covering 4 million miles a year, roughly to the moon and back eight times. By using the system, easyJet estimates 50,000 tonnes of fuel and the associated CO2 emissions could be saved annually.
The only waste product from the system is fresh clean water which easyJet says could be used to refill the aircraft’s water system throughout the flight.
The airline has a track record in developing concepts and new technologies for aircraft. In 2007 it unveiled the EcoJet, which featured two rear-mounted open rotor engines, and claimed to be 50% more fuel efficient and 25% quieter than aircraft such as the Airbus A320 or Boeing 737. The airline hoped at the time the aircraft could be in operation by 2015. Then in 2010 it announced it was to trial a volcanic ash detection system involving infra-red technology that would allow aircraft to fly safely around ash clouds. This time the AVOID technology was subsequently deemed a success and was due to enter production by two suppliers.
“At easyJet, we are continuing to apply the use of new digital and engineering technologies across the airline,” said Head of Engineering, Ian Davies. “The hybrid plane concept is both a vision of the future and a challenge to our partners and suppliers to continue to push the boundaries towards reducing our carbon emissions.”
EasyJet has been looking at green taxiing solutions for a number of years and in February 2012 announced it would support Safran and Honeywell in the development of the joint venture’s electric green taxiing system (EGTS). Asked to comment on its current involvement with the ongoing project, a spokesman for easyJet told GreenAir: “EGTS is available and is something we have supported.”
However, the EGTS uses the aircraft’s Auxiliary Power Unit (APU) to power motors on the main wheels – another system being developed by WheelTug uses the APU to drive a nosewheel-mounted motor instead – and easyJet says this requires an upgrade to the APU.
“Using a hydrogen fuel cell to power the taxiing system does not and therefore become viable,” he said. “We believe this will be cost-effective to implement and run.”
Last year easyJet signed a three-year strategic partnership agreement to share innovation and knowledge with Cranfield University, which will continue to work with the airline on the hybrid plane concept. As part of easyJet’s 20th birthday activities, Cranfield students were asked to take part in a competition to develop ideas for what air travel might look like in another 20 years’ time.
“Our students have showcased some exciting ideas for the 2035 vision of the airline industry through The Future of Flight competition, presenting environmental solutions, operational improvements and ideas to enhance the customer experience,” said Dr Craig Lawson, Lecturer at Cranfield’s Centre for Aeronautics. “We’re looking forward to developing this concept further.”
The easyJet spokesman said the first step was to develop a working group consisting of Cranfield and suppliers. “Ultimately, our goal is to develop a mock-up and a working example in the coming months.”
The airline has set new emissions targets for 2020 that include a 7% reduction in its carbon footprint over the next five years compared to today, which stands at 81.05 grams CO2 per passenger kilometre, itself a decrease of 28% over the last 15 years. It claims an easyJet passenger’s carbon footprint is 22% less than a passenger on a traditional airline, flying the same aircraft on the same route.
