In October 2022, after intensive diplomacy at a meeting of the International Civil Aviation Organisation (ICAO) in Montreal, 184 countries agreed an aspirational goal of making the aviation industry net neutral of carbon emissions by 2050.
Ireland has a key global role in this ambition. Approximately 58 per cent of all civil aircraft worldwide are leased and, of these, about 50 per cent are leased through more than 30 leasing companies operating in Ireland.
Financing business models used to be based on the solvency of an airline operator, its business model, the age of the aircraft and their residual values. Now the emissions impact is becoming an increasingly significant factor.
The recent winner of The Irish Times Innovation Awards (disclosure: I was the chairman of the judging panel), PACE, is well positioned to assist. The company accurately measures the carbon emission impact globally from existing aviation operations, down to the granularity of specific individual flights and occupied seat classes (eg business or economy).
The analysis can be aggregated across airlines, and specific aircraft models and configurations, and also for particular airports. The raw data is taken from live flight-tracking data collected worldwide, including some data made available via industry partnerships.
The ICAO goal is ambitious. By 2050 the aviation industry expects to have emission-free aircraft using electric engines, with highly efficient fuselage shapes, including blended wings and high aspect-ratio configurations. However, aircraft rolling off production lines today will almost certainly still be flying in 25 years’ time, given aircraft lifetimes.
The big challenge is, therefore, not developing exciting new designs for roll-out towards 2050, but rather how can today’s aircraft fleets be upgraded while in service in the years ahead to become fully net carbon neutral by 2050?
Sustainable Aviation Fuel (SAF) is typically made from waste oils and residues, and potentially from direct carbon capture systems. By recycling carbon already in the atmosphere, SAF avoids releasing additional carbon into the air. Fortunately it is compatible with jet fuel and so kerosene and SAF blends can fuel existing jet engines.
However, SAF can cause rubber hoses and seals in fuel tanks and engine fittings to become brittle and susceptible to leakage over time. Both Airbus and Boeing have undertaken to enable retrofitting of existing fleets with new fuel-line systems capable of enduring high SAF concentrations.
[ Green aviation fuel industry could be worth €2.55bn to IrelandOpens in new window ]
Currently, SAF is approximately twice as expensive as traditional jet fuel and accounts for only about 1 per cent of global jet fuel consumption. The European Union Safety Agency has predicted that about 2.3 million tonnes of SAF would be needed annually to reach just 5 per cent SAF usage across the EU by 2030. At present, EU production is only one 10th of that.
Hydrogen is a longer-term potential jet fuel replacement. It would be emission-free but only if the hydrogen itself is also produced without emissions, presumably by renewable electricity electrolysing water.
Although very light for a given amount of energy, hydrogen has a low volumetric density and requires extremely low temperatures and high pressures to be stored. Existing fuel tanks cannot be used and new cylindrical tanks are required for hydrogen in aircraft. Hydrogen also burns at a higher temperature than traditional fuel, a challenge for existing jet engines.
Airport ground operations and supply chains worldwide will also need heavy investment, almost certainly with support from national governments, to manage and store hydrogen fuel.
Airbus has committed to producing an entirely new aircraft model powered by hydrogen by 2035. Derwent Technologies, a specialist UK company, has proposed a dual SAF-hydrogen adaptor for existing jet engines, which would automatically switch between SAF for high-power situations (such as take-off and go-around) and hydrogen fuel only for low-power cruise so that the engine would be undamaged. Hydrogen would be carried by external underwing storage tanks. Derwent claims that existing short-haul aircraft could thus be converted to partial use of hydrogen fuel.
[ Green hydrogen: Cause for hope or hype?Opens in new window ]
Nature is also providing inspiration. The Lufthansa group is using sharkskin technology to reduce friction in flight and so reduce fuel consumption, as I discussed in September. Meanwhile, migrating geese are showing the way to the aircraft manufacturer. The Airbus “fello’fly” project demonstrated how air turbulence behind an aircraft, which is usually avoided by other aircraft, could be exploited by a trailing aircraft to reduce its own fuel burn by 5 to 10 per cent. Normally aircraft are separated by at least 30 nautical miles for transoceanic flights but, as a demonstration, the project paired two A350s from Toulouse to Montreal separated by only 1.2 nautical miles. The tactic is inspired by migrating flocks of geese, flying in V-formation, where each bird benefits from reduced drag because of the bird in front.
A number of airlines, Boeing, Eurocontrol and other partners are now joining Airbus in a follow-on EU Horizon-funded initiative to develop cockpit functions and flight management support to track and exploit wake vortexes. Aircraft could be safely paired for long-haul flights if navigational and air traffic procedures can be evolved appropriately.
With the imminent Trump administration, carbon neutrality goals seem likely to diverge between the US and rest of the world. That could well allow Europe and Airbus to consolidate a leadership position.
- Sign up for Business push alerts and have the best news, analysis and comment delivered directly to your phone
- Find The Irish Times on WhatsApp and stay up to date
- Our Inside Business podcast is published weekly – Find the latest episode here
