Hydrogen aviation in the West of England

The West of England’s aerospace cluster includes an active component working on decarbonisation technologies. The Jet Zero Taskforce (a UK government and industry partnership to accelerate the decarbonisation of aviation) includes members from Airbus, Rolls Royce and ZeroAvia; all of which have sites in the West of England. GKN Aerospace’s Global Technology Centre in Filton has several programmes researching hydrogen-based technologies. ZeroAvia has also conducted some of the UK’s first test flights of hydrogen-fuelled planes at its site in Kemble (Cotswold Airport), while Vertical Aerospace has flown short-range aircraft using both battery and hydrogen-powered systems.

Decarbonising aviation: what are the options?

Air travel is inherently difficult to decarbonise. Flying is energy-intensive and passenger aeroplanes need to be safely airborne for as many as 19 hours without refuelling. Kerosene propulsion systems rely on globally available, energy-dense and lightweight fuel. The current kerosene-based air transport industry has developed over the course of a century of continuous iterations and improvements in safety and efficiency.

New fuel systems and technologies will only be viable if they can match the flight duration capacity, reliability and economy offered by conventional propulsion systems. Battery technologies are currently too heavy to be adopted for long duration flights or large aircraft. While sustainable aviation fuel (SAF) – synthetic kerosene usually made from biomass – can significantly reduce CO2 emissions, it is expensive, land-intensive and challenging to produce in sufficient quantities.

As a result, many experts consider hydrogen propulsion systems the likeliest solution for emission-free flight.

How viable is hydrogen as an aviation technology?

A number of barriers remain before the successful commercial deployment of hydrogen aviation, from technological maturation to regulatory approval and logistical integration.

Infrastructure must be developed to operable capacity. Aviation-enabling systems on the ground must effectively function alongside one another. Manufacture and transportation supply chains must deliver a sufficient quantity of fuel, requiring a mature network of hydrogen-equipped airports and sufficient generation capacity from renewable sources (as hydrogen from natural gas won’t produce emissions savings).

Significant technical challenges onboard the aircraft must be overcome in fuel storage, propulsion and the energy transfer through the system. Hydrogen propulsion systems involve storing fuel on the plane either as a compressed gas (suitable for small aircraft) or in cryogenic tanks (necessary for commercial-scale aircraft). Fuel is converted to propulsion: compressed gas systems use a turbine; fuel cells power an electric motor and propeller. The development of fuel storage, energy transfer and propulsion must all reach suitable efficiency to enable flight.

Due to the technological maturity of kerosene-based propulsion systems, research and innovation today focus on efficiency improvements, rather than viability itself. Development of hydrogen fuelled aircraft requires a broader focus. As outlined by one of our research participants, a senior technical officer, R&D is ongoing on everything “from how the fuel is delivered to the aircraft, how the power generation is achieved through fuel cells, how electrical power is distributed and managed”, the design of electric motors and “utilising the cryogenic properties of hydrogen to develop hyper-conductive thermal networks and drive systems”.

Opportunities for the region: a history of aviation innovation

The aerospace industry in Bristol traces back to 1910 when George White founded the Bristol Aeroplane Company. Filton, in the north of Bristol, remains an important industrial cluster where the successors to the Bristol Aeroplane Company (BAC) – Rolls Royce and BAE Systems – retain a presence. The original BAC hanger is now an Airbus site. Cotswolds Airport, formerly RAF Kemble, is another longstanding testing and development asset.

There is a diverse mix of companies within the region’s aerospace industry, including original equipment manufacturers (OEMs), including Airbus and Rolls Royce, and Tier 1 suppliers – partners that design, manufacture and deliver major systems or large aerostructures directly to OEMs – such as GKN Aerospace and Thales. There are also R&D-intensive start-ups like ZeroAvia and Vertical Aerospace.

One of our interview participants, an employee at a large aerospace company, reflected on the deep talent pool in the region: “We've got a really rich aerospace ecosystem in the South West, particularly around the Bristol area, in terms of access to customers, specialist resources, people. You've got BAE [Systems], you've got MBDA, you've got Airbus, you've got Leonardo. There's a real rich vein of aerospace talent in the region.” This allowed firms to recruit from a deep talent pool as projects ended, company priorities shift and employees look for different opportunities.

This was further highlighted by the Chief Technology Officer (CTO) of an aviation start-up, who explained that the UK offers an internationally competitive combination of talent and cost advantage compared with other countries, including the United States.

A key factor in R&D viability is the availability of external and public funding. The UK’s Aerospace Technology Institute (ATI) provides funding for aviation research and innovation projects, mirroring similar national grant-making organisations like LIT in the Netherlands and FMV in Sweden, as well as transnational bodies like the European Space Agency (which also provides funding to UK-based organisations).

Funded by the Department for Business and Trade (DBT), the ATI matches up to 50% of a project’s research and innovation costs, with the remaining finance coming from industry. This assistance facilitates commercially unviable projects and attracts them to the UK.

Due to the extent of the research and innovation required to develop mature hydrogen aviation technology, state support is vital for giving companies the capacity to innovate. There was consensus across interview participants that the ATI plays a significant role in ensuring that innovation occurs in the UK and the creation of British jobs.

When might hydrogen technology reach maturity?

Hydrogen propulsion remains some way off replacing kerosene-based systems in commercial aviation. Much of the research being done today is ground-based and focused on proving technical possibility.

Current test flights use Part 23 planes. These aircraft, which sit a maximum of 19 people, are used by private individuals and smaller operators for short-haul routes, freight or tourism. Pending regulatory approval, some Part 23 planes hope to reach market within the next five years. Beyond small aircraft, scaling the technology remains a significant technical challenge. The next target engine size is a 2 megawatt (MW) engine system, which would be capable of powering planes with up to 100 people but requires four times the power of current technologies.

Conclusion

The West of England is well-placed to engage with the technical challenges associated with next-generation aviation but to do so effectively requires a commitment from companies and continued financial support from grant-making organisations. Even without introducing products to market, important progress is being made here towards the technology, supply chains and regulatory maturity that will be necessary for hydrogen aviation to succeed.

References

Interviews:

Participant B - CTO, low-carbon technology start-up 

Participant N - Senior Technical Officer, Aviation Company