2021-2025: a 5-year programme to advance fuel cells for aviation
Martin Goodwin, Head of Aerospace Programmes, and Tim Booth, Head of Product Development, IE-FLIGHT take us through the past 5-years of aerospace development at Intelligent Energy under the H2GEAR programme with GKN Aerospace.
H2GEAR is ending, but its impact on Intelligent Energy is only just beginning.
Over five and a half years, the programme helped shift our role in hydrogen aviation from specialist fuel cell contributor to developer of complete aviation power systems. It laid the technical and commercial foundations for IE-FLIGHT and for HEIGHTS, the £17 million programme now taking that work into a market-ready system.
H2GEAR, short for Hybrid Hydrogen Electric Architecture, was a major UK programme led by GKN Aerospace and supported by the Aerospace Technology Institute (ATI). Its purpose was to develop scalable hydrogen-electric propulsion technologies for future aircraft, bringing together industrial and academic partners from across the country.
For Intelligent Energy, the programme marked the point where years of fuel cell development became a clear aviation product strategy. We joined H2GEAR to contribute our hydrogen fuel cell expertise to the wider propulsion system. The programme accelerated our capability, strengthened our credibility and created the momentum that now underpins HEIGHTS, where we are leading development of a complete aviation fuel cell system.
HEIGHTS, which stands for Hydrogen Efficient fuel cell Integrated in a High Temperature System, is focused on delivering IE-FLIGHT, including a 300kW modular aviation fuel cell platform designed for eVTOL, sub-regional and regional aircraft.
Martin: from the start, H2GEAR was about more than one project
When H2GEAR started, we knew we were contributing to something bigger than a single fuel cell programme. The goal was to help prove whether hydrogen-electric propulsion could become a practical aviation technology.
H2GEAR was one critical step in a broader plan to bring hydrogen fuel cell systems into aviation. It was large, complex and highly visible, bringing together six partners, three industrial and three academic, around a shared ambition to develop scalable hydrogen-electric propulsion technology for the next generation of sustainable aircraft.
Intelligent Energy’s contribution focused on the fuel cell module at the heart of that architecture. Alongside the significant technical progress, H2GEAR gave us the opportunity to work closely with a major aerospace partner and raised our profile across the sector. We are now part of conversations and programmes that would not have been open to us five years ago.
That’s important because credibility in aerospace is built over time. It takes technical depth, consistency and long-term commitment. H2GEAR gave us the platform to demonstrate all three.
Tim: turning fuel cell know-how into something fit for aerospace
As Head of Product Development for our aerospace-focused products, I have spent the past four years leading the technical design of our aviation fuel cell system and the test capability that supports it.
Drawing on our experience from our IE-DRIVE products, H2GEAR focused on developing a fuel cell stack module from the ground up to meet aerospace requirements.
The results have been significant:
- a 50% reduction in system mass
- a 30% increase in volumetric power density
- improved thermal performance
- faster transient response
- a threefold increase in stack module power density
At system level, those gains mean lower drag, reduced cooling demand and faster power response. All critical factors because they affect aircraft efficiency, safety and overall operating performance.
Recent work at our new test facility in Northamptonshire has demonstrated the fast transient response of the evaporatively cooled fuel cell. This is important because slower fuel cell response requires the electrical network to carry additional energy reserves, adding mass to the overall system to maintain safety.
In parallel, our collaboration with the Civil Aviation Authority through the Hydrogen Challenge has given us valuable insight into certification requirements and pathways.
Martin: it was never just about hitting a headline number
At the start of the programme, one of the primary technical targets was to increase power density in line with the ATI roadmap. That benchmark gave the engineering team a clear focus. By the end of the programme, the design had delivered a threefold increase in stack module power density, a major step forward on the journey towards an aviation product.
One of the most important lessons from H2GEAR is that aviation readiness cannot be defined by a single metric. Aircraft performance depends on the behaviour of the whole propulsion system. Mass, drag, thermal management and transient response all matter.
If the fuel cell can respond quickly when the pilot demands power, the energy storage system can be smaller. If the heat exchanger is smaller, drag reduces and block fuel efficiency increases, leading to an improved aircraft-level proposition.
This is what made H2GEAR so valuable. It allowed us to demonstrate that the stack module could meet the targets when integrated into a representative aircraft architecture.
Tim: one of the biggest gains was the engineering base we built
A significant part of H2GEAR’s value came not just from the fuel cell technology, but from the engineering capability we built around it.
This included system architecture, testing capability, research methods and analysis tools. One of the major deliverables was our test equipment, designed to support TRL 4 testing and higher power levels for future products. That work now feeds directly into the next phase of aviation development. Our Northamptonshire test facility will accelerate testing and validation of high-power fuel cell systems for flight.
We also made strong progress in modelling and digital analysis, creating tools that now underpin how we design and integrate our systems. These capabilities help us understand system behaviour, explore design trade-offs with greater speed and reduce integration risk before hardware is built.
This is one of the reasons H2GEAR transfers so directly into HEIGHTS. We are carrying forward a proven stack module and specialist expertise that spans system integration, verification and certification readiness.
Martin: why HEIGHTS is the obvious next step
If H2GEAR proved the technology, HEIGHTS is turning it into a product.
HEIGHTS builds directly on the foundations laid by H2GEAR. Under this programme, Intelligent Energy has moved from contributing to a wider consortium effort to leading development of the full system, including the balance-of-plant around the stack module.
That represents a significant shift for Intelligent Energy. It means taking the core technology proven through H2GEAR and turning it into something customers can assess, test and ultimately deploy.
Tim: the picture is more realistic now
Our understanding of hydrogen in aviation has matured significantly over the course of H2GEAR. Five years ago, the focus, both internally and across the industry, was on achieving high power density. That still matters, but H2GEAR has shown that a high-performing stack alone does not translate directly into a viable aircraft solution.
Today, the emphasis is on developing fuel cell power modules that integrate effectively within the aircraft, taking account of drag, packaging constraints, thermal management and interfaces with the wider propulsion and energy system.
We are also designing with through-life operation in mind, including durability, maintainability and predictable performance in an operational environment.
This will introduce a new system architecture alongside an aerospace controller, helping us meet the safety levels aviation demands. The technology is still developing, but this strategy gives us a realistic path to certification.
Looking back, and ahead
If we had to sum up H2GEAR in a single line, it would be this: it changed Intelligent Energy’s role in hydrogen aviation.
It strengthened our engineering base. It deepened our relationships across the aerospace sector. It demonstrated that our fuel cell technology has a credible role to play in future aircraft propulsion.
H2GEAR proved that hydrogen fuel cells can meet the demands of aviation. HEIGHTS is about turning that proof into aircraft-ready systems. For Intelligent Energy, that transition is already underway.
Want to find out more about our fuel cells for aerospace? Get in touch or visit our IE-FLIGHT web page here.