Beginning with the introduction of a mid-size hydrogen-powered aircraft by 2035 and a narrowbody aircraft by 2037, aircraft types powered by liquid hydrogen represent the greatest opportunity for reducing carbon emissions and maximising market impact, concludes the 12-month FlyZero study funded by the UK government. The project demonstrated aviation can achieve net zero 2050 through the development of both sustainable aviation fuel and green liquid hydrogen technologies. Global cumulative CO2 emissions from aviation could be reduced by 4 gigatons (Gt) by 2050 and 14 Gt by 2060 but this requires 50% of the commercial fleet to be hydrogen-powered by 2050, says the Sustainability Report just published by the Aerospace Technology Institute (ATI). Led by the ATI and backed by the UK government, FlyZero began in early 2021 as an intensive research project investigating zero-carbon emission commercial flight, reports Mark Pilling.

The study brought together experts from across the UK to assess the design challenges, manufacturing demands, operational requirements and market opportunity of potential zero-carbon emission aircraft concepts. The intention is that FlyZero will shape the future of global aviation with the objective of gearing up the UK to stand at the forefront of sustainable flight in design, manufacture, technology and skills.

“Realising zero carbon flight is one of the most ambitious challenges we can contemplate. However, it could also be one of the biggest economic opportunities for the UK’s world leading aerospace sector,” said UK Industry Minister Lee Rowley.

Added Chris Gear, FlyZero Project Director: “Zero-carbon emission flight can be a reality. Tackling the challenge of our generation requires accelerated technology development and urgent investment in green energy together with regulatory and infrastructure changes.”

To secure market share on new hydrogen-powered aircraft, UK companies must be ready to demonstrate technologies by 2025, said FlyZero. This timescale is key for new zero-carbon emission aircraft to enter service by 2035 and to achieve the net zero 2050 target. FlyZero concludes green liquid hydrogen is the optimum fuel for zero-carbon emission flight and could power a mid-size aircraft with 280 passengers from London to San Francisco directly, or from London to Auckland with just one stop. Introducing a midsize hydrogen-powered aircraft by 2035 and a narrowbody aircraft by 2037 represents the greatest opportunity for reducing carbon emissions and maximising market impact, insists FlyZero.

In order to meet these timelines, the study says revolutionary technology breakthroughs are required in six areas to achieve zero-carbon emission flight: hydrogen fuel systems and tanks, hydrogen gas turbines, hydrogen fuel cells, electrical propulsion systems, aerodynamic structures and thermal management. The UK has expertise and capability today in these, but little in liquid hydrogen fuels, points out the report, and the nation requires a hydrogen research and development facility with open access for academia and a range of industries including aerospace, automotive, marine, space and energy. Developing a new generation of aircraft will present an opportunity to integrate sustainability into design and manufacture, and further improve the reuse of materials, says FlyZero.

From the mid-2030s, liquid hydrogen will be cheaper than power-to-liquid, which it expects will the most widely available sustainable aviation fuel. Its scenario foresees no requirement for PtL SAF by 2060. However, generating the quantity of hydrogen needed for aviation will require unprecedented renewable energy capacity. Transporting hydrogen to airports will necessitate gaseous pipelines or liquid hydrogen tanker deliveries, while refuelling aircraft will require larger diameter hoses and increased automation to ensure it can take place safely and efficiently alongside other aircraft.

The optimum route to decarbonising aviation, found the FlyZero team, is through the accelerated introduction into service of a large commercial aircraft similar to the project’s mid-size concept which is capable of reaching anywhere in the world with just one stop. Less commercially risky than developing a narrowbody first, this mid-size first approach would also allow infrastructure development to be focused on fewer, but larger international hub airports.

The report says research into the climate impact of emissions from hydrogen gas turbines including through modelling and testing is fundamental alongside the technology development. It states that although burning in a gas turbine emits no CO2 or SOx, water emissions are over 2.5 times higher than for fossil fuel-powered aircraft. Particulate matter will largely be eliminated, it adds, and it is estimated that NOx emissions will be reduced by 50 to 70%.

According to FlyZero, the UK can build on decades of expertise in aerospace innovation to propel a new generation of liquid hydrogen-powered aircraft, working with global OEMs, governments, and regulatory bodies. With targeted investment in technology, the UK could grow its market share in civil aerospace from 12% today to 19% by 2050, increasing the sector’s gross value added to the economy from £11 billion to £36 billion ($14 – 47bn) and the number of aerospace jobs from 116,000 to 154,000.

The ATI has published a series of open-source reports that form the conclusions of the FlyZero project. A series of more detailed and technical reports, together with supporting research from industry and academia, are available to organisations that meet the requirements of an access test.

Image: The three FlyZero hydrogen-powered concept aircraft (© ATI)

Mark Pilling

GreenAir Contributing Editor

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A UK government-backed aerospace research project has unveiled a midsize, liquid hydrogen-powered, zero-carbon concept aircraft capable of flying up to 279 passengers non-stop from London to destinations as far away as San Francisco or Beijing, or around the world to Auckland with just one stop. Led by the government-funded Aerospace Technology Institute (ATI), a team of around 100 UK aerospace and aviation experts have collaborated on the FlyZero project to demonstrate the huge potential of liquid hydrogen in regional, short-haul and long-haul flight. Detailed findings from the project are due to be published in early 2022, including on regional and narrowbody as well as midsize concept aircraft, technology roadmaps, market and economic reports, and a sustainability assessment. The midsize unveiling coincides with the fourth meeting of the government/industry Jet Zero Council that has been tasked by the UK prime minister of developing a zero-emission transatlantic aircraft “within a generation”. The government has also announced the eight winning proposals that will share £15 million ($20m) in funding towards the development of sustainable aviation fuel production plants in the UK.

“Fuelling planes sustainably will enable the public to travel as we do now, but in a way that doesn’t damage the planet,” forecast Kwasi Kwarteng, the UK government’s Business Secretary. “It will not only help us to end our contribution to climate change, but also represents a huge industrial opportunity for the UK.”

He said the FlyZero concept aircraft could define the future of aerospace and aviation. “By working with industry, we are showing that truly carbon-free flight could be possible, with hydrogen a front-runner to replace conventional fossil fuels.”

Liquid hydrogen is described by the ATI as a lightweight fuel with three times the energy of kerosene and sixty times the energy of batteries per kilogramme and emits no CO2 when burned. Realising a midsize longer-range aircraft also allows concentration of new fuelling infrastructure to fewer international airports that could help accelerate the rollout of a global network of zero-carbon emission flights to tackle hard-to-abate emissions from long-haul flights, it adds.

The 279-passenger (pax) midsize aircraft concept has a range of 5,250 nautical miles and so would sit between the 244-pax/4,700nm Airbus A321 XLR and the 296-pax/7,560nm Boeing 787-9. ATI says the midsize concept would meet the demands of a unique sector of the market between single aisle and widebody aircraft operations, which together account for 93% of aviation’s carbon emissions.

The liquid hydrogen fuel would be stored in cryogenic fuel tanks at around minus 250 degrees C in the aft fuselage and two smaller ‘cheek’ tanks along the forward fuselage. The cheek tanks also serve to keep the aircraft balanced as the fuel burns off and eliminate the need for any additional aerodynamic structures. The concept aircraft’s 54-metre wingspan – compared to the 787-9’s 60 metres – carries two turbofan engines powered by hydrogen combustion.

FlyZero believes this new generation of hydrogen-powered aircraft will be able to benefit from the lower fuel supply costs that will come as other sectors also move towards hydrogen energy. As well as being zero emissions, they will also have superior operating economics than conventional aircraft from the mid-2030s onwards, it says.

“At a time of global focus on tackling climate change, our midsize concept sets out a truly revolutionary vision for the future of global air travel, keeping families, businesses and nations connected without the carbon footprint,” said FlyZero Project Director Chris Gear. “This new dawn for aviation brings with it real opportunities for the UK aerospace sector to secure market share, highly skilled jobs and inward investment, while helping to meet the UK’s commitments to fight climate change.”

Added the government’s Transport Secretary, Grant Shapps: “This pioneering design for a liquid hydrogen-powered aircraft, led by a British organisation, brings us one step closer to a future where people can continue to travel and connect, but without the carbon footprint.”

The fourth meeting is due to take place today of the Jet Zero Council, a partnership between government and industry, which is co-chaired by Shapps and Kwarteng. “I will continue to work closely with the Council to support the UK’s world-leading research in this sector, which will create green jobs, help us meet our ambitious net zero targets and lead the global transition to net zero aviation,” said Shapps.

Commenting on the FlyZero concept aircraft, the Council’s CEO, Emma Gilthorpe, who is also COO of Heathrow Airport, said: “This ground-breaking green technology looks set to play a critical role in decarbonising flight and through the work of the Council, the UK aviation sector is exploring all avenues to ensure we protect the benefits of flying for future generations while cutting the carbon cost.”

Low-cost carrier easyJet, which is a member of the Council, welcomed the concept aircraft development as it sees hydrogen-powered aircraft playing an important role in its decarbonisation pathway. The airline has seconded one of its pilots, Debbie Thomas, to the project to use her engineering background and flying experience.

“The concept aircraft demonstrates the huge potential of green liquid hydrogen for aviation, including larger gauge aircraft, and I’m very excited to see where we go from here,” said David Morgan, Director of Flight Operations at easyJet. “We are closely involved in the work of the ATI and its FlyZero project and we look forward to continuous collaboration to make -zero-carbon emission flights a reality as soon as possible.”

FlyZero was launched by the government in July 2020 as a 12-month project, with the outputs to be made available for further development and exploitation, and the benefits shared with a wide cross-section of stakeholders to support growth in the UK. Funding has been committed to the ATI until 2030 under a recent government spending review, although details have yet to be released. To date, £1.6 billion ($2.1bn) has been awarded to over 340 collaborative R&D projects across all UK regions, with the aim of supporting the development of innovative aerospace technologies in line with the government’s commitment to reducing aviation emissions whilst driving growth.

As well as backing the FlyZero liquid hydrogen aircraft project, the government is also funding projects looking to develop sustainable aviation fuel production plants in the UK through its £15 million Green Fuels, Green Skies Competition. The following eight companies have been awarded grants towards projects with their early-stage development:

Advanced Biofuel Solutions (£2,054,000)
alfanar Energy (£2,417,500)
Fulcrum BioEnergy (£1,372,957)
Green Fuels Research (£1,940,255)
LanzaTech UK (£3,152,619)
LanzaTech UK and Carbon Engineering (£340,674)
Nova Pangaea Technologies (£484,201)
Velocys Projects (£2,381,000)

Research has indicated that by 2040, a UK SAF sector could generate between £0.7 billion and £1.66 billion a year for the economy, with potentially half of this coming from the export of intellectual property and the provision of engineering services, and create between 5,000 and 11,000 green jobs.

Photo: The JetZero midsize concept aircraft

Rolls-Royce has completed ground testing of an aircraft that will aim to break the world speed record for all-electric flight early next year. The technology has been tested on a full-scale replica of the plane’s core, called an ‘ionBird’, that includes a 500hp electric powertrain and a battery with enough energy to supply 250 homes. The plane is part of an initiative called ACCEL – short for ‘Accelerating the Electrification of Flight’ – with half the funding for the project being provided by the Aerospace Technology Institute (ATI), in partnership with the UK government’s Department for Business, Energy & Industrial Strategy (BEIS) and Innovate UK. Rolls-Royce has also agreed to partner with ATI and Boeing on a three-month accelerator programme to support and back start-ups creating sustainability-enabling technologies to help the UK aerospace industry innovate and recover from the Covid pandemic.

“Rolls-Royce is committed to playing a leading role in reaching net zero carbon by 2050,” said Rob Watson, Director – Rolls-Royce Electrical. “The completion of ground testing for the ACCEL project is a great achievement for the team and is another important step towards a world record attempt. This project is also helping to develop Rolls-Royce’s capabilities and ensure that we remain a leader in delivering the electrification of flight, an important part of our sustainability strategy.”

The testing involved running the propeller up to full speed of approximately 2,400 rpm using what Rolls-Royce claims is the most power-dense battery pack ever assembled for aircraft propulsion. Over 6,000 cells are packaged in the battery for maximum safety, minimum weight and full thermal protection, it said.  Other companies involved in the project are YASA, a manufacturer of axial-flux electric motors and controllers for automotive and aerospace applications, and Electroflight, a technology and engineering services business that supplies bespoke battery systems for the aerospace sector.

The first flight is planned for later this year, with an attempt on beating the current all-electric flight world speed record expected to follow next year. The project is also the first at Rolls-Royce to use offsetting to make the whole programme carbon neutral.

“The ACCEL team is pioneering the integration of high-performance batteries, motors and drives to deliver an electric propulsion system in an ambitious flight test programme. These technologies and the systems integration needed to utilise them hold great potential for future sustainable aviation, which is why the ATI is proud to support the project,” said the ATI’s Mark Scully, Head of Technology for Advanced Systems & Propulsion.

Added UK Business and Industry Minister Nadhim Zahawi: “The completion of ground testing for the government-backed ACCEL project is not only a step towards an exciting world record attempt, but a leap towards developing all-electric and hybrid-electric planes that one day could ferry large numbers of passengers around the world.”

Created by the ATI and Boeing, and run by leading European accelerator Ignite, Rolls-Royce is joining the accelerator programme’s second cohort, which has opened applications to invest into sustainability-enabling start-ups that will benefit the UK aerospace industry across three key areas of focus: Industry 4.0, Lifecycle and Resilience, and Energy. This includes innovative energy and energy storage solutions such as battery lifecycle optimisation, alternatives for rare earth materials, hydrogen management solutions and sustainable aviation fuels.

Selected companies may receive £100,000 ($128,000) equity investment from Boeing HorizonX Global Ventures, together with first-hand access to strategists and technical experts from the programme’s partners and corporate sponsor GKN Aerospace. In light of the new Rolls-Royce partnership, applications for cohort two have been extended and will close on October 4. The programme will be running two cohorts a year, with each cohort made up of 8-10 start-ups, and is open to companies domiciled outside the UK.

“Having worked alongside the ATI, Boeing and GKN Aerospace, we’ve seen how much start-ups appreciate the access to top-class resources that these companies offer and we are incredibly excited about the opportunities that our next cohort will receive through our partnership with Rolls-Royce,” said Gabi Matic, Programme Director at ATI Boeing Accelerator.   

In July, the ATI launched the government-backed FlyZero project with the aim of accelerating the adoption of more sustainable technology solutions and achieve zero-carbon commercial flight by the end of the decade. It plans to identify the zero-carbon technology solutions that could bring the largest impact to reducing overall aviation emissions in support of the UK government’s 2050 net-zero objective. An overview of the project was presented in a webinar held in August.

Photo: Rolls-Royce ACCEL