HEIGHTS: high temperature fuel cell systems for zero-emission flight
Jonathan Douglas-Smith, Head of Business Development for Aerospace at Intelligent Energy, updated us on the progress being made in the HEIGHTS programme and recapped the strategic significance of our participation in this year’s ATI Conference ‘Destination Zero’.
Last week’s Aerospace Technology Institute (ATI) conference – Destination Zero – marked an important step for Intelligent Energy’s work in hydrogen aviation. For the first time, ATI invited us to deliver a lead presentation on progress within the HEIGHTS programme, focusing on one of the toughest challenges in hydrogen-electric propulsion: keeping fuel cells cool in flight without adding weight or drag.
That invitation reflected a shift in perception. Five years ago, Intelligent Energy was a supporting partner on GKN Aerospace and ATI’s H2GEAR project. Today, ATI sees our technology as a key enabler to unlocking the thermal management problems faced by programmes such as those led by Airbus and GKN. The UK’s aerospace innovation body now positions Intelligent Energy’s technology as a leading potential problem-solver for hydrogen propulsion.
To recap, the HEIGHTS programme – Hydrogen Efficient fuel cell Integrated in a High Temperature System – is a three-year project backed by the ATI, the Department for Business and Trade and Innovate UK. Its goal is to deliver a 300kW net modular aviation fuel cell system ready for integration in electric vertical take-off and landing (eVTOL) and Part 23 commuter aircraft.
Initial flight applications are expected by the end of the decade, with scale-up for regional aircraft in the 2030s. If adopted across the sector, the technology could help cut up to 25 million tonnes of CO₂ emissions a year and support thousands of high-value UK jobs.
The difference that Intelligent Energy brings to this project lies in our cooling method. Most aviation fuel cell developers use glycol-based systems that require large radiators, heavy pumps and high flow rates to circulate the coolant. Intelligent Energy’s patented evaporative cooling system uses the evaporation of water to cools the cells rather than circulating liquid flow, reducing coolant mass flow rates by greater than 90%.
The result is a system that is smaller, lighter and simpler to integrate. As others face the limits of liquid cooling, there is growing interest in our architecture and its potential to resolve a fundamental barrier to flight-ready hydrogen systems.
Validation, milestones and the year ahead
Packaging and drag reduction are of critical importance in aviation. When HEIGHTS launched in June, we estimated a 20–30% reduction in frontal area compared with glycol-based systems. Updated modelling by an independent specialist has now confirmed an expected mass reduction of around 41% and 47% lower aerodynamic drag in the case of a fixed-wing 9-seater aircraft application. The simulations are based on empirical test data from previous generations of our system, providing a high degree of confidence in the results.
The next step is physical validation through our high-temperature demonstrator. This laboratory system will confirm that the cooling architecture performs as predicted and will mark the final technical milestone before integration.
Meanwhile, progress continues at our Chelveston facility in Northamptonshire, which will be completed early next year. Once operational, Chelveston will enable full-power testing of aviation systems using locally produced green hydrogen.
In the coming 12 months, our engineers will finalise the design and bill of materials of our IE-FLIGHT 300kW net through-life fuel cell system, then move into component sourcing, assembly and testing. From a commercial standpoint, the focus will be on building partnerships and securing funding to take the system into its first flight phase. On current timelines, we expect an experimental Intelligent Energy fuel cell system to fly in 2028.
As HEIGHTS focuses on the total power system – not just the stack – we continue to work closely with specialist partners including the University of Sheffield’s Advanced Manufacturing Research Centre, Coventry University and the Manufacturing Technology Centre. Each contributes valuable expertise in advanced design, testing and integration.
From supporting role to spotlight
Our presence at Destination Zero was more than just a conference appearance. It reflected the growing recognition of Intelligent Energy’s technology and the role it can play in enabling practical, zero-emission flight. ATI’s decision to highlight our progress signals a broader confidence that the UK’s hydrogen aviation ecosystem can deliver solutions on a global scale.
Cooling may sound like a technical detail, but in aviation it determines the feasibility of flight. Through HEIGHTS, Intelligent Energy is showing how a smaller, lighter and more efficient thermal management system can make hydrogen-electric propulsion commercially viable and bring zero-emission aircraft closer to reality.
Interested in learning more about the HEIGHTS programme and our high temperature fuel cell systems for aviation? Get in touch or head over to our FLIGHT page.