Embracing the rainbow: Exploring hydrogen’s role in decarbonising aviation at regional airports - Article by Paul E Eden, Regional Gateway, July 2025

With hydrogen considered to be a key element in decarbonising aviation, regional airports are likely to provide proving grounds for critical related technologies. However, hydrogen is not a straightforward solution and the challenges are great, as Paul E Eden discovers.

Aircraft and aviation infrastructure have relied upon hydrocarbon fuel since Charlie Taylor built the four-cylinder gasoline engine that successfully propelled the Wright Flyer through an epoch-making series of flights on 17 December 1903.

The direct reliance of infrastructure upon fossil hydrocarbons has reduced as renewable electricity gradually enters national grids, but the high energy density of hydrocarbon molecules identified by the Wrights when they chose gasoline power more than a century ago, means hydrocarbon fuel is likely to remain the primary commercial aircraft power source for decades to come.

Particularly for smaller aircraft, there is perhaps a role for battery and hydrogen fuel cell propulsion, the latter consuming hydrogen as a fuel and exhausting water as waste product.

Hydrogen fuel cells already power ground vehicles to a limited extent, and applications for hydrogen as a fuel for electricity generation and even domestic heating have been suggested, not least under the UK government’s Hydrogen Strategy.

The SAF connection – How hydrogen could support sustainable aviation fuel production

In a perfect world every turbine-engined aircraft will burn 100 per cent sustainable aviation fuel (SAF) sooner rather than later. There are multiple routes to SAF, all requiring a carbon feedstock and, in many cases, hydrogen as a key ingredient.

Even if controversial grown biomass feedstocks are removed from the equation, the earth is rich in carbon through sources as diverse as sewage and carbon dioxide (CO2) extracted directly from the air.

Meanwhile, hydrogen, the most abundant element in the universe, is most commonly found on Earth combined with oxygen as water and, ironically, in fossil hydrocarbon molecules.

Extracting hydrogen is invariably an energy-intensive process. Storing and moving it also poses significant challenges, which industry understands well.

Which is to say that were hydrogen to be used as a fuel on a macro scale, then existing steel-based infrastructure, pipelines, storage tanks and so on associated with hydrocarbon fuels could not be used, since hydrogen reacts with steel.

Another challenge lies in gaseous hydrogen’s very low volumetric energy density compared to hydrocarbons, likely restricting its fuel use to ground and building applications unless it can successfully be stored and moved in bulk, in liquid form.

UK-based CirculAIRity is clear in its vision to “enable the decarbonisation of the [aviation] sector by producing synthetic SAF derived from the Direct Air Capture of CO2.”

More specifically, Alex Chikhani, the company’s CEO and founder, says: “We put our arms around everything, including the primary power source and real estate. We aren’t scaling up our own technology, in fact, we’re technology, power source and location agnostic. We aim to manage the end-to-end supply chain.”

Chikhani describes SAF production as “extremely power hungry”, noting that the energy return per litre of SAF is 20:1, meaning that 20 “units” of energy are consumed to create every one unit of energy released when SAF is burned.

Hydrogen extraction is the most energy-intensive stage in the SAF production process. “Extracting hydrogen, like the manufacture of power-to-liquid fuels, requires energy, but not necessarily electricity,” Chikhani carefully explains.

“Waste heat from industrial processes can be used instead of electricity. So can heat from the sun – it makes little sense from a physics point of view to use sunlight to generate electricity and then use that to extract hydrogen or drive the chemical process that make fuel when we could use the sun’s heat directly.

“There are several ‘colours’ of hydrogen, of which ‘green’ is the most well known. It uses renewable power to extract hydrogen by electrolysis and very little of it is available.

“Most of the hydrogen on the market is ‘blue’, from natural gas, dependent on a fossil fuel and relatively cheap to produce, but if aviation is to decarbonise, then it must eliminate fossil fuels from the SAF production cycle. ‘Pink’ hydrogen uses electricity from a nuclear power station while ‘red’, which remains in the research stage, uses heat from a reactor to split water molecules.

“We’re looking at nuclear as just one of our potential power sources, including the advantage of ‘red’ hydrogen.”

Regional reaction – Trialling hydrogen application at regional airports

The barriers to widescale hydrogen extraction and employment are therefore great, but not insurmountable.

Proving its application at airports is an important component in aviation’s sustainability imperative and the very best locations for real-world trials are smaller, regional airports, where modified infrastructure may be installed with minimal disruption and stakeholders remain close for easy discussion and expedited progress.

Meanwhile, early steps are already being taken, and they are, inevitably, small.

Education and messaging are important elements in the wider sustainability effort and a single hydrogen-powered truck at a regional hub, for example, is likely far more newsworthy than a similar vehicle at a major primary airport.

A case in point is Exeter Airport in the UK, which recently completed a trial using a hydrogen-powered baggage tug, pushback tug and ground power unit to turn around a TUI Boeing 737 aircraft.

Stephen Wiltshire, Managing Director at Exeter Airport, says: “Regional airports are most likely to be those handling the first generation of smaller hydrogen aircraft, so it makes sense they should be the focus of any testbed activities.”

Similarly, in Canada, Edmonton International Airport is partnering with Diesel Tech Industries (DTI) to explore the integration of the Guardian Hydrogen Diesel System on two of the airport’s heavy-duty runway snow sweepers.

Currently operating on diesel fuel, the runway snow sweepers will be retrofitted using the DTI’s hydrogen diesel system to use hydrogen as a supplementary fuel, thereby significantly reducing carbon emissions without requiring extensive infrastructure modifications.

In the Baltics, under the BSR HyAirport programme, a hydrogen-powered Mulag baggage truck was tested at Riga Airport during March.

The programme includes regional airports in Germany, Poland, Scandinavia and across the Baltic region – and in winter 2025/26 expects to see hydrogen-powered winter machinery on test in Helsinki, Tallinn and Riga.

Julian Klaaßen, the BSR HyAirport Project’s Financial and Communications Manager, is based at Hamburg Airport.

He tells Regional Gateway: “The main goal is to create a decision-making tool and some rough calculations for every user – primarily airport operators – to help integrate hydrogen into different airport locations by answering questions like what costs are estimated for fuel and does local production or delivery make more sense?

“Since everything depends on location and every location is different, a general, variables-based outcome is needed. Generating that is the business case behind the whole project.”

Demonstrating hydrogen applications and safety in real-world operations is integral to the BSR HyAirport effort.

Klaaßen adds: “It is also very important for us to share results and show to a broad public audience that safe operations are possible.”

He is in no doubt that regional airports and airline routes will lead in hydrogen applications, adding: “At Hamburg Airport we are on the case with both infrastructure and hydrogen fuel cell-powered aircraft, while we have a healthy small aviation sector as well.

“Regional aviation will be the first mover, with larger aircraft following at least a decade later. Regional passenger flights are especially significant in the Baltics and Scandinavia, driving interest in electric – for short range – and hydrogen – gaseous for short range and liquid for medium range – aviation.”

Will hydrogen replace other energy sources?

Today, airports might store Jet A1, SAF and avgas for aircraft, petrol (gasoline), diesel and compressed natural gas (CNG) for ground vehicles, and offer electric charging points. In a rose-tinted future, could hydrogen replace some of these energy sources and associated infrastructure?

Klaaßen says: “It could represent a huge opportunity for synergy across services and hydrogen could simplify some elements of airport operations, but other fuels will still be used in parallel.

“Petrol and CNG might vanish, for example, but jet fuel will remain for at least 30 years and most probably longer, hopefully as SAF. Hydrogen will therefore be just another fuel to be delivered and stored.

“In an integrated concept, it might provide opportunities for business synergies and simplification, but the integration and transition will pose challenges, with competition for airport space and additional infrastructure required in the early stages too.”

In common with Klaaßen, Chikhani cautions that hydrogen alone is not the solution to humanity’s future energy requirements – and therefore neither will it entirely power tomorrow’s airports and aircraft.

“Firstly, hydrogen is difficult to handle,” he says. “It can’t be moved or stored like natural gas, for example. Hydrogen needs stainless steel or glass vessels, or maybe some very specific plastics.

It just leaks from steel and with its activation energy being so low it is very combustible – static from clothing is a sufficient ignition source.

“Aluminium aircraft and steel infrastructure have been built around and matured on almost a century’s worth of kerosene – Jet A1 – being the primary energy source for aviation.

“The idea that everything can be switched to hydrogen is highly unlikely. We need to look at a macro system, applying appropriate expertise throughout the system.”

By its nature, aviation is among the most difficult sectors to decarbonise. In 2024 it was a relatively small contributor to the world’s total carbon emissions at around three per cent, although its effect on global warming was surely greater through other high-altitude emissions, including water vapour.

The latter is volumetrically more significant than CO2 as a greenhouse gas and has significant climate effects, albeit shorter-lived for each emission, than CO2. More worryingly, however, it enhances the warming effects of the latter.

As other industries successfully decarbonise, aviation’s contribution to global warming will become proportionally greater and it is important to realise that the goal here is to reduce global warming for the benefit of the planet and continued survival of society.

This is not about making aviation greener for accounting purposes, this is about stopping emissions and ultimately reversing the damage already done.

Hydrogen as a fuel and SAF component is critical to that goal.

Chikhani says: “It will take time and depends on the commitment of countries, legislators and populations, nationally, regionally and globally, to enact this level of change.”

Regional airports are the obvious crucibles in which the aviation industry might trial hydrogen and other energy technologies, proving them in limited commercial service before any extension into major hubs.

Chikhani and Klaaßen are optimistic about the likelihood of success, while acknowledging that fundamental questions remain, such as: Where does the hydrogen come from? Who makes it? Who sells it? How is it regulated? What infrastructure is required and who pays for and maintains it?

“We are seeking answers,” Klaaßen says. “In the process, we are speaking to stakeholders whom, as airports or aviation operators, we have never spoken to before, because we can only answer these questions in co-operation with other industries. Without co-operation, we will never achieve our goals.”