Decarbonizing long-haul flights represents a “colossal challenge” and the use of technologies such as hydrogen, batteries and fuel cells to power widebody aircraft is still “many decades” away, according to Eurocontrol.

After evaluating a number of alternatives to kerosene and sustainable aviation fuel (SAF) for the purpose of powering a hypothetical widebody flight from Paris to Singapore, Eurocontrol concluded in a recently-published think paper that “all of these are many decades away from evolving to meet our challenge of decarbonizing a typical long-haul flight”.

Long-haul flights of over 1,864mi (3,000km) accounted for 9% of departures from the UK and European Union in 2019 but were responsible for 54% of Europe’s aviation-related carbon dioxide emissions that year, the report points out. If no major progress is made, it adds, this could rise to 60% by 2050 — the year by which the global air transport industry has committed to achieve net zero carbon emissions. 

In addition to liquid hydrogen, electric batteries and fuel cells, Eurocontrol examined the potential for methane, liquid ammonia and solar energy to power future long-haul flights.

It concluded: “[A] widebody that could be powered by any of these technologies on their own, or in combination, cannot be expected in the foreseeable future. Advances in solving many of the technological challenges outlined in this paper will happen, but significant progress is not expected to take place for decades at the earliest.”

Each of the six solutions, adds Eurocontrol, is “highly unlikely to emerge for application to classic widebodies used to fly long-haul routes” — especially as these aircraft types tend to remain in service for an average of 23 years.

In setting out its net zero ambitions in October 2021, the International Air Transport Association (IATA) envisioned that new propulsion technology such as hydrogen could account for 13% of the required mitigation of 1.8 gigatons of aviation-related carbon in 2050. Under IATA’s vision, sustainable aviation fuel (SAF) would achieve 65% of the abatement, with carbon capture and storage accounting for 11%, offsets making up 8%, and the remaining 3% coming from efficiency improvements.

Eurocontrol’s findings cast doubts on the industry’s assertion that new propulsion technologies could provide the second-largest reduction in its carbon footprint by the middle of the century. For instance, its report suggests that while a long-haul aircraft using liquid hydrogen combustion would be able to take off and land, “a large cryogenic tank and supporting infrastructure is lacking”. What’s more, such an aircraft “would also produce significant contrails that would need to be further studied”.

Airbus, however, takes a much more optimistic view of hydrogen and is aiming to develop the world’s first hydrogen-powered commercial aircraft by 2035 through its ZEROe research program. One of the concepts under the program is a blended-wing aircraft design which, Airbus says, could seat 200 passengers and operate flights of up to 2,300mi. Alongside the program, Airbus is in the process of analyzing the impact of hydrogen combustion on contrail development through its ‘Blue Condor’ project.     

The European airframer is also developing a hydrogen-powered fuel cell engine. It plans to start ground- and flight-testing the fuel cell engine architecture onboard its ZEROe demonstrator aircraft toward the middle of this decade. Airbus said late last year that its A380 MSN1 flight test aircraft was being modified to carry liquid hydrogen tanks and associated distribution systems. 

Despite such developments, Eurocontrol believes that in the short- to medium-term, a “different approach” to technologies such as hydrogen, batteries and fuel cells is required if the industry is to make “significant progress” toward decarbonizing long-haul flights. It plans to publish another think paper, which it says will tackle “what can be achieved using other existing or easy-to-envisage technical and operational solutions”.

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