Wings of change: Aviation in a low-carbon world
Our recent industry roundtable brought together leading experts from fields spanning energy, transport, sustainability, academia, manufacturing and technology to discuss the future of flight. Chris Seekings reports
Aviation has radically transformed travel during the past century, bringing people closer together and redefining the way we do business, take holidays, deliver medical aid and transport goods. The industry also accounts for an estimated 2% of global greenhouse gas emissions and 12% of transport-related CO2, with its contribution to climate change rising fast.
However, amid growing public awareness of the state of the environment, plans are under way to overhaul the way the whole sector operates, from boosting energy efficiency to redesigning the means of long distance travel altogether. Here, a group of 23 leading experts from fields spanning energy, manufacturing, technology, academia, sustainability and transportation work through the many challenges facing aviation as it looks to thrive in a low-carbon world.
James Cameron, a member of Heathrow 2.0’s advisory group and chair of the roundtable discussion, gets the ball rolling by asking about the latest technological innovations.
“We have been looking at the two key limitations of composite materials used in aircraft: a lack of motility and relatively low toughness,” says Paul Robinson, head of the department of aeronautics at Imperial College London. “We have built on our understanding of current materials and are looking to improve them, with a focus on controlled stiffness and shape measuring, and most recently looked at applying these to a morphing wing.”
One of the most exciting developments around new materials concerns their ability to actually store power once in flight. “We have also been looking at materials that not only perform structurally, but also can store electrical energy, which is particularly relevant to the electrification of aircraft currently under way,” Robinson explains.
The UK government has just closed a consultation into the future of aviation, and envisages that hybrid or all-electric aircraft will be in service by 2050. This follows the successful short-distance flight of the E-Fan all-electric aircraft across the English Channel in 2015, while Airbus and Rolls Royce’s E-Fan X demonstrator is in the developmental stage. It is hoped that this will help establish certification requirements and pave the way for electric air travel across Europe.
“The pressure is on to move as rapidly as we can towards reduced or even zero-emission aviation, and there are now full development programmes moving forward hybrid and all-electric solutions,” says John Turton, aerospace committee member at the Institution of Mechanical Engineers. “The 2050 timeframe certainly seems feasible to me, but it’s a process of taking one step at a time and we are only at the start of this process. It would seem that a long-haul electrical hybrid is still a long way off, though.”
Breaking down barriers
“The elephant in the room here is life-cycles. Each fleet replacement cycle is a $5trn investment and takes around two decades”
Ron van Manen, Clean Sky 2 programme manager
There is agreement that the electrification of long-haul aircraft will be a hard nut to crack. A report from consultancy firm Roland Berger highlights that there are 169 projects for small electric aircraft under way. Two-to-four-seat electric planes that can travel 50 miles are already possible, while 400-mile flights with 10 seats should be available within the next decade.
“My problem is that anything under 50 seats in the current air transport system contributes just 1% of fuel burn; everything over that contributes 99%, so the challenge is how we scale these technologies,” says Ron van Manen, programme manager at the EU’s Clean Sky 2 partnership. “If we can get that technology up to 50 or 100 seats and up to 600 miles or 1,000 miles, it gets interesting. But if the needle sticks at no more than, say, 10 or 20 passengers and a few hundred nautical miles, it’s not going to have any impact.”
It is put to the panel that a new type of fuel may be necessary, with the energy used for long-haul flights likely to remain based on combustion and gas turbines in the short term. “New energy storage technologies offer an alternative to fossil fuel sources in favourable circumstances,” explains Anthony Powell, research division lead at the University of Reading. “However, the implications for materials resources should not be underestimated. For example, reserves of the key components of lithium-ion batteries, while sufficient to meet growth in electrification of vehicles, may be insufficient to address increased demand from other sectors.”
Among the largest challenges are the weight of aircraft and the height at which they travel – both have a high impact on fuel burn. The panel also posits price as a barrier. It is not currently possible to fit existing aircraft with electric motors – electrification requires a complete design change. “The elephant in the room here is life-cycles,” van Manen says. “Each fleet replacement cycle is a $5trn investment and takes around two decades, and what is being delivered now by manufacturers will still be in service in 2035. Conversely, in order to have a fleet in 2050 that is genuinely ‘low-carbon’, that generation of aircraft would need to become available in the 2030s. We need to work on that technology in the next five to 10 years, or it won’t be on time. We can’t go to airlines and say ‘you have to make another $5trn investment, straight after the last’.
”This leads to a discussion around design change and what this will mean in practice – not just for aircraft, but also for airports and surrounding infrastructure. “It is about connections in the physical space,” Cameron says. “Electric flights might need a 45° launch, while hydrogen-based craft could need huge wing spans – there are all different kinds of vehicles with different spatial requirements. It’s challenging.”
A whole-system approach
If there is a big shift to electric aircraft, do you recharge the planes on arrival or replace their batteries to achieve acceptable turnaround times? What are the safety implications of holding vast amounts of battery storage at the airport? Batteries will increase landing weight, possibly leading to increased landing speeds. What will that mean for runways and air traffic control? “You have all these implications of electrification that you have to consider,” says Ken Hart, aerospace engineering lecturer at the University of Hertfordshire. “The airport infrastructure is all connected to the aircraft associated with it.”
There is also the question of actually getting passengers to the aircraft. Road traffic causes more CO2 emissions than aviation, so perhaps this whole process needs to be redesigned. “You could start sending people in pods directly to the aircraft, which would allow you to move the airstrip miles from the terminal and reconfigure how the airport interacts with the plane,” muses Geoff Rodgers, vice provost at Brunel University London.
The panel also discusses how different goods will be transported around airports in the future. It is suggested that dirigibles fitted with GPS tracking, rather than planes, could be responsible for freight and transport of heavy goods, for example. These could be passed to smaller vehicles for delivery, creating a different picture of movement in and out of airports.
Either way, it is agreed that electrification and potential redesigns are going to require multi-skilled delivery teams. “We will need to think about the planes, how they sit on runways, and secondary and tertiary support,” says Ian Smyth, director at UK Power Networks Services, who estimates that electrifying all long-haul aircraft in the UK will require around 5% of the country’s total electricity consumption. “This will need a whole-system approach, bringing together aeronautical and electrical engineers, along with environmental groups.”
Lessons to be learnt
When it comes to planning new infrastructure projects, Smyth explains that there are lessons to be learnt from the electricity system. “We work to the “four Ds’: democratise, digitise, decarbonise and decentralise,” he says. “It is a moral obligation to allow people use of electricity as they see fit – we must move away from restriction of choice through limiting carbon and allowing consumers choices which are sustainable.”
He highlights how previous infrastructure projects have been let down by a failure to include energy professionals in the early planning stages. “You have the bulldozers come in, then the civil engineers, the mechanical engineers, the structural engineers, and then electrical engineers. We need electrical infrastructure in the early stages because the low-carbon technologies are proven and ready to be applied to new projects.”
However, there is some scepticism among the panel members about the feasibility of new projects. “There is no infrastructure whatsoever to produce the electric charging needed for aviation,” van Manen says. “When you consider the challenge of electrifying around one billion cars on the road, aviation can probably learn some lessons in terms of thinking a little bit too optimistically.”
Anticipating future trends and their impact on infrastructure is critical for airports. Heathrow’s chief strategy officer, Andrew Macmillan, was enthusiastic about emerging possibilities. “We can start to see how radical decarbonisation of flying could happen, but the challenge then shifts to making it real. Take electrification – as we are able to forecast the timing of take-up more accurately, we can start to plan long-term infrastructure. We must ensure we can meet future demand, but also ensure we have a reliable energy source.” Being able to map out the pace and implications of change is the central challenge.
Many smaller businesses already have grand designs for the future of aviation infrastructure. The convergence of renewable energy, storage, digital demand, electric vehicles and sign management is under way and could soon produce inexpensive and abundant power. “I think when we are making an investment case for electrification at an airport, we need to learn lessons from other projects like High Speed 2,” Smyth says. “What are the triple bottom line benefits? It has to be cheaper, better for customers and better for the environment.”
No time to waste
“If you look at emissions, it is a huge challenge for aviation. I think that if Greta Thunberg was here she would be pushing that urgency”
Nick Blyth, IEMA policy and engagement lead
All this talk of timeframes, price, technology and infrastructure design raises concerns that the aviation industry’s current efforts are incompatible with the urgency of the climate crisis. A report from the Intergovernmental Panel on Climate Change (IPCC) published last year warned that the world only has until 2030 to avoid uncontrollable global warming.
“As a sector, planned frameworks like the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) do not go far enough,” says IEMA policy and engagement lead Nick Blyth. “You have got a voluntary scheme starting in 2021, and a mandatory one beginning in 2027, but then we have the IPCC saying we only have 11 years to bend the curve on emissions. Policy has to do more to support innovation and be more biting.”
This discussion takes place after weeks of protests from Extinction Rebellion, with the activist group said to be planning action at Heathrow Airport. Meanwhile, the climate strike movement has seen more than 1.5 million young people protest against government inaction on climate change – a sentiment that is likely to be shared by a group of Imperial College London aeronautics students observing this discussion.
“Extinction Rebellion has brought emotional language to the debate on climate change,” says Richard Templer, director of innovation at Imperial College London’s Grantham Institute. “This is fantastic but tends to demonise activities such as flight. We need to take air transport emissions to zero while enabling the societal, economic and political benefits that it has created.”
However, a UN report released in 2016 revealed that, by 2050, the aviation sector could be consuming a quarter of the world’s carbon budget if it does not meet its emission targets. The industry is aiming to cap its emissions at 2020 levels, but air travel is expected to increase by around 5% per year up to 2034, and there were more than four billion passengers in 2017 alone.
“You are up against it if you look at historic emissions and recent ones, it is a huge challenge for aviation against that backdrop,” says Blyth. “I think that if someone like Greta Thunberg was here, she would be pushing that urgency.”
Changing the language
Emissions offsetting comes in for criticism, with some members of the panel raising concerns about the use of language. “When you look at offsetting and hear that you can offset a flight’s emissions for ¢80 or €1, it’s hard sometimes to imagine how that actually works,” says Blyth. “Things have improved with better standards, but I think there is still some greenwash under way.”
He also argues that the concept of carbon neutrality can be improved on. “There is too much focus on offsetting, but the neutrality picture also needs to be geared towards innovation and transition,” Blyth says. “The issues of avoidance and efficiency are underplayed, so I think we need to evolve this concept of becoming carbon neutral and apply it in a different way.”
Cameron agrees, saying that ‘offsetting’ can be a misleading term that distracts from businesses’ other obligations. However, he highlights the fact that good ideas have come about when carbon is a value by governments or private contracts, and argues that there should be a deeper discussion around how resources derived from offsetting are deployed. “We need to start thinking harder about where to channel the revenue streams effectively from offsetting or carbon prices,” he says. “At least CORSIA gives us something to work with, and we might be able to accelerate progress through the International Air Transport Association.”
There are also concerns around how the issue of emissions is framed. Templer says that more emphasis needs to be placed on emissions as a pollutant, and that airlines should present themselves as part of the clean-up operation.
“If you describe carbon as a pollutant, then the cost of emissions is the cost of cleaning it up, so it becomes a financial transaction,” he says. “You can’t just ignore your emissions, and what do you do when you pollute? You should clean up and let you customers know you want change – this is a rallying cry.”
“I think every time you fly, you should actively be reducing the net amount of CO2 in the atmosphere – that would be a transformative message”
Richard Templer, Grantham Institute director of innovation
When it comes to solutions, there is agreement that the industry will need to think beyond current proposals. Templer suggests that aviation team up with other hard-to-decarbonise sectors, pooling resources to develop the technologies of the future. “I think every time you fly, you should actively be reducing the net amount of CO2 in the atmosphere,” he says. “Airlines and airports should ally with the cement and steel industries to create technologies that remove carbon, so customers know that every time they fly they are helping the environment. That would be a transformative message.”
Tapping into customers’ perceptions of aviation is something that comes up again and again. “Start investing in these carbon removal technologies and businesses so that customers see you as part of the solution,” Templer adds.
Moving back to the topic of long-haul flights, there are some who question whether these will even exist in the same way in decades to come. It is suggested that a higher number of short distance flights may be the way forward. “Will long-haul, wide-bodied aircraft still be flying in a net-zero world? Personally, I don’t know, but the potential for innovation, particularly in short-haul flights, is still something we are exploring, for example through concepts such as our eVTOL,” says Rachael Everard, head of sustainability at Rolls-Royce.
The panel discusses how travelling shorter distances more often could transform the industry. “In a previous organisation we did research into capital utilisation, and thought about how aircraft might not be owned by airlines in future, but just travel from east to west in hops, with passengers opting in for certain flights,” says Gary Cutts, director at Innovate UK’s Future Flight challenge. “The whole business model may change, driven by consumer’s demand for low-carbon travel.”
Some are unsure whether customers would be willing to be more eco-friendly if it meant big changes to their journeys. “Accepting a 20-minute longer trip across the North Atlantic could lead to a 20% to 30% carbon saving, and airlines will generally tell you that their customers won’t accept that,” van Manen says. “But I think passengers choose on the basis of maintaining their gold card, the quality of the seat, the reliability of the airline, the lounge they like, the airport they like – consumer preference is not necessarily the same as the perception of many airlines.”
It is also suggested that different technologies may need to be matched to different flights. “It’s a fascinating challenge, and there could be a great variety of services offered,” says Cameron. “There will be issues around pricing those services, but the market is rewarding innovation right now. It might not even be delivered by a recognised name in the aviation industry, but by a specialist in digital systems.”
“Will long-haul, wide-bodied aircraft still be flying in a net-zero world? The longevity of the industry is still something we are trying to understand”
Rachel Everard, Rolls Royce head of sustainability
Reasons for optimism
This discussion has highlighted various challenges and opportunities facing aviation’s path to carbon neutrality, and will be used to frame how Heathrow’s Centre of Excellence for Sustainability designs new projects, to begin later this year.
The industry is buoyed by increasingly efficient and affordable green technology, and few expect airline traffic flows and business models to be the same in 2050 as they are today. The prospect of customer engagement excites the panel. “It may be that the industry doesn’t understand the appetite for these changes among the public,” Cameron says. “There may be something alluring about that change, and many may have had some consciousness-raising by Thunberg and her company.”
But who should drive these changes? Templer argues that airlines and airports must show leadership. “Because airlines have direct contact with customers, they have both the opportunity and responsibility to enter into a purposeful dialogue about how to decarbonise flight,” he explains. “Leadership in such dialogue means that the questions that are solicited are pertinent, based in potential solutions and are never neutral about the climate change impact of flying as it currently operates. You have to be saying ‘we know what we have to do, and this is what we want to do’.” This carrot-rather-than-stick approach is something that is welcomed strongly by some on the panel.
From a broader perspective, it is agreed that strong collaboration will be key to rethinking how and where we fly, the speed, height and distance of travel, and how this is matched with various different technologies. This is something Rolls-Royce is already doing by teaming up with smaller companies. Everard says: “The opportunity and challenge for larger firms is how to harness the energy and culture of a smaller company or start up, and working out how we can scale up and develop these technologies, including potentially bringing them in-house.”
Cutts highlights that there is an appetite for collaboration among stakeholders. “We know that aviation is quite compartmentalised, but the people we have talked to have shown a great desire to work with new entrants and find solutions together.”
Collaboration and systemic thinking will be critical as aviation comes under increasing public and regulatory pressure, but the industry has had to face numerous other existential challenges in the past. “Ask a good engineer, or even a good artist, and they will tell you that creativity and constraint go together,” Cameron says. “All creativity emerges within the construct of a constraint, but when you see an electric aircraft move, for example, it changes your consciousness, and I do see huge optimism.”