Aviation technology is due to reach new heights over the course of the next decade, as efficiency improvements, advancements in fuel development and new forms of propulsion take to the skies. It could usher in a new age of flight.
Plane travel’s path forward has arguably cleared significantly in 2020, as governments and regulators have started to lay the groundwork for ambitious climate and transport policies at national and EU level.
Aerospace and aviation firms at least know that they will be expected to make increasingly green improvements to the way they do business and the aircraft they build in the coming years.
The aviation industry is by no means a sector that is set in its ways and averse to change, as far as technology is concerned. Airlines have been renewing their fleets for a number of years to tap into improved fuel efficiency and savings.
Latvian carrier airBaltic, for example, now operates a fleet made up just of Airbus A220-300s, in order to reduce supply chain complexities and to take advantage of the smaller aircraft’s market-leading efficiency stats.
“At the moment, it is the greenest commercial aircraft in the world, as it is the first to have a transparent declaration of the life-cycle environmental impact, helping to reduce CO2 and NOx emissions by 20% and 50% respectively,” the airline said in a statement.
In response to the coronavirus pandemic, which has led to the early retirement of larger, older aircraft that cannot be operated at a profit with reduced passenger numbers, airlines are increasingly turning to fleet renewal as a way to protect their bottom lines.
Airbus CEO Guillaume Faury recently called for ‘cash-for-clunker’ initiatives, where airlines would be paid to trade in their older aircraft. Although Faury’s main reason for suggesting it is to generate more business for his firm, such schemes could also reduce emissions.
Engine and airframe improvements are not the only steps forward currently taking place, other pollution-curbing measures include air traffic management reforms. The European Commission estimates that in Europe it could slash emissions 10%.
There are also substantial fuel savings to be made by deploying innovative flight patterns: a fledgling scheme involving Scandinavian Airlines, EUROCONTROL, Airbus and more aims to replicate how migratory birds fly in formation but for planes.
Engineers estimate that planes could save 5-10% of their fuel per long-haul flight by sitting in the wake of a leading aircraft. Tests are ongoing and hope to be rolled out for commercial flights by 2025.
Burnishing the environmental credentials of current aircraft designs is an exercise in diminishing returns that is almost certainly insufficient to enable aviation to hit its carbon-neutral targets later this century.
Attention is turning more and more towards what aircraft are actually fuelled with. Kerosene is a fossil fuel and no matter how efficient an engine is, it will emit CO2 when burned.
Sustainable Aviation Fuels (SAFs) – low carbon alternatives to fossil kerosene, produced from waste streams or a mixture of waste CO2 and clean energy – are generating industry interest as a result.
SAFs are drop-in fuels that are compatible with most modern aircraft. Boeing recently demonstrated that a 50/50 blend of SAF and kerosene – the current maximum permitted by international standards – is perfectly feasible.
Rolls-Royce, which builds engines for both Airbus and Boeing, has started testing engine design concepts that are capable of running a 100% blend, which could prove to be a game-changer for airlines.
“These tests are a contribution to the SAF debate, aiming to demonstrate that our current engines can operate with 100% SAF as a full ‘drop-in’ option, laying the groundwork for moving such fuels towards certification,” said Rolls-Royce’s Paul Stein.
Tests are due to wrap up this month and early results will be available in the New Year.
The net emissions of the fuels being tested by the firm are certified to be 75% lower than conventional kerosene but in real-world applications the main obstacle is proving to be price, as well as supply and demand.
SAFs made from waste materials can cost between two to five times more than kerosene – a difficult prospect for airlines that are struggling to stay afloat and haemorrhaging thousands of jobs. Fuels made from clean energy are even more expensive.
But the European Commission has identified the problem and will next year reveal its ‘ReFuelEU’ plan, which will reportedly include a blending mandate that will give SAF producers a guaranteed market to tap into and scale up production.
Less than 1% of Europe’s fuel demand is met by SAFs and an initial draft of a new transport plan had included a 5% target for 2030, which would have risen to 60% by 2050. Those goals were missing from the finalised version.
EU climate boss Frans Timmermans said that “we thought we could do better than what was written in the initial draft”, when asked by reporters why the targets had disappeared.
In the meantime, industry is pressing ahead regardless. Airlines like SAS already book SAF as Norway has a blending mandate in place, with Finland and Sweden set to follow suit soon.
Freight giants DB Schenker and Lufthansa Cargo operated their first SAF-fuelled flight in November between Frankfurt and Shanghai in November, offsetting the remaining emissions not covered by the fuel blend. More regular CO2-neutral cargo shipments are planned.
Regulators will have their work cut out to settle who can actually claim the emissions cuts provided by SAFs on their books, while environmental groups are concerned that biofuel-based fuels will recreate policy mistakes made in past years in road transport.
‘Revolution not evolution’
Drop-in fuels and offsetting schemes may neutralise emissions on paper but they ultimately do not stop CO2 and other greenhouse gases being released into the atmosphere. That means that other options will be needed to truly green aviation’s operations.
According to Axel Krein, Executive Director of Clean Sky, a private-public partnership tasked with developing innovative green technologies to reduce aircraft CO2 emissions and noise, the industry “needs revolution not evolution” to go climate-neutral by 2050.
“There is no one silver bullet: we need to bring all these different elements together in order to meet the targets,” Krein told the Aeromart Summit earlier in December.
Several options are under consideration and at different stages of development, ranging from electric-battery power to hydrogen fuel cells and even a complete redesign of what we would consider an aircraft.
Clean Sky is currently working on a concept for a plane that is capable of vertical take-offs and landings, similar to a helicopter, but which will cut CO2 emissions by half and noise by 30% making it more suitable for use in cities and built-up areas.
A full-scale demonstrator is due to launch in 2023 but there are plenty of obstacles that need to be tackled beforehand, including the complex tilting mechanism for the wing.
Electric-battery tech promises zero-emission flight if the plane is charged up using renewable energy but current power-to-weight constraints mean small aircraft with short flight times are the limit of its reach.
But the EU’s aviation safety regulator recently certified an electric aircraft for global use, in a worldwide first, and state of the art batteries, driving mostly by demand in the road transport sector, are making the prospect of e-planes less unlikely.
Airbus and Rolls-Royce nixed a project aimed at developing a hybrid short-haul plane earlier this year due to the impact of the pandemic but there are still around 215 different projects currently in development.
Tesla’s Elon Musk recently said “electric airplanes with decent range, comfortably over 1,000 kilometres, need batteries with about 400 watt-hours per kilogram. We’re getting there progressively, with energy density improvements every year.”
The current generation of batteries hover around the 300 Wh per kg mark and each improvement cuts the overall cost, as less material is needed to construct the more powerful batteries. Costs are also plummeting.
A more immediate cure for the range anxiety of aviation heads is hydrogen power, which can match kerosene in terms of flight distance potential and only emits water vapour if the fuel is generated using clean energy.
But hydrogen aircraft are at an even earlier stage of development. Airbus recently announced plans to debut a plane by 2035, while smaller scale companies are aiming to retrofit existing aircraft just to demonstrate the technology.
The Commission’s new mobility strategy wants to see planes in the sky by 2035 as well and the €750 billion in virus recovery funding that is due to be released next year has been identified as a major source of cash that can be used to step up development.
Upcoming changes to the EU’s carbon market, which include reducing the number of free pollution permits available to airlines, as well as the billions of euros on offer under different innovation funds are poised to accelerate development further.
The 2020s could well usher in a new age of flight if all of the industry’s moving parts successfully align. Evidence suggests that aviation is now well-placed to pull it off.
[Edited by Benjamin Fox]