3 July 2022

GreenAir News

Reporting on aviation and the environment

UK FlyZero project concludes liquid hydrogen is the optimum fuel for zero-carbon flight by 2050

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)