Fuel from waste, hydrogen and electric-powered aircraft could help decarbonise aviation, but commercialisation will be far from simple
Few sectors have been harder hit by the pandemic than aviation. But as vaccine rollouts help ease restrictions and the industry plots a route back to profitability, it’s facing another existential threat: the pressure to decarbonise.
Today, aviation contributes around 2-3% of global greenhouse gas emissions, but is on course to become the second-highest emitter in 2050 as other sectors reduce their impact. Due to the technological leaps required to reduce sector emissions, experts say the groundwork must begin now if the world is to meet the targets agreed in the Paris Climate Change accord.
Given the turmoil of the last 18 months, the timing couldn’t be worse. But despite the adversity, the industry is responding. Last September airline alliance oneworld announced that all 13 of its members, including British Airways, have committed to net-zero emissions by 2050.
Governments are also outlining their ambitions for the sector. The UK is one of the biggest exporters of aerospace products and services globally. This month the government, as part of its £125m “Jet Zero” ambition to deliver the first zero-emission trip across the Atlantic, launched a strategy consultation on how Britain can become a vanguard of progress.
Technologies for change
“There’s no silver bullet or single technology that we believe can achieve carbon neutrality by 2050,” warns Bram Peerlings, consultant for sustainable aviation at Netherlands-based research centre NLR and co-author of a report on decarbonising aviation, called “Destination 2050”.
Still, NLR believes that different solutions have different timelines: “operational improvements can be implemented fairly quickly, whereas large-scale use of sustainable fuels and especially the implementation of radical technology will take longer, as time is required for further development and commercialisation”, Peerlings says.
The report states that 92% of industry-associated CO2 emissions from flights departing from the EU and UK can be reduced in-sector. The remainder will require carbon capture and forest planting.
In some ways, the pandemic has expedited improvements in emissions reductions already. KLM Royal Dutch Airlines and British Airways both retired early ageing Boeing 747s for more efficient carriers. It’s estimated that next-generation models of aircraft, such as the Airbus A320neo, improve fuel efficiency by around 20% compared to their predecessors.
But it will take more than a fleet upgrade to get the industry to where it needs to be. In the short term, replacing kerosene or blending it with sustainable aviation fuel – known as SAF – is one of the most promising. Made from renewable feedstocks such as waste oils and agricultural residue, SAF can lower carbon emissions by 70% compared to conventional jet fuel.
SAF is currently two to three times as expensive as conventional jet fuel, and production is only 0.05% of total EU jet fuel consumption. To incentivise its development, this month the European Commission proposed a progressive tax on polluting jet fuel, which was previously exempt, as well as increasing minimum SAF blends to 2%, rising to 5% in 2030 and 63% in 2050. The World Economic Forum’s Clean Skies for Tomorrow initiative also hopes to boost SAF use with a certificate programme launched in June that enables companies to pay a premium for the fuel when flying, which can then be used in their Scope 3 carbon emissions accounting.
SAF needs no new infrastructure or equipment investment, unlike electric and hydrogen-powered planes, which require entirely new engineering. Despite the difficulty, it’s looking like shorter commercial routes could be using electric planes within the decade. In a notable move, United Airlines in July announced it would buy 100 19-seat electric planes from Swedish start-up Heart Aerospace, on condition they meet safety, business and operating requirements. The zero emission planes can fly customers up to 250 miles and use electric motors instead of jet engines, and batteries instead of jet fuel. They’re expected to be operational in 2026.
It’s unlikely that battery power would ever be viable for bigger aircraft, though, due to the weight of the batteries. But there will likely be levels of “hybridisation” along the way, according to Mark Howard, head of commercial strategy for FlyZero, a £15m UK government-funded initiative delivered by the Aerospace Technology Institute (ATI). Its remit is to outline a future decarbonisation framework for the sector.
The Destination 2050 report calculates that range and capacity-optimised hybrid-electric aircraft could reduce CO2 emissions by 50% for smaller, regional-class aircraft.
For larger carriers, green hydrogen or ammonia-powered planes are currently considered the front-running technology. However, these aren’t expected before 2035 due to due to the necessary technological and supply chain development.
Howard, who has worked for Airbus for 35 years, says FlyZero’s current thinking is that liquid cryogenic hydrogen – which is minus 253 degrees Celsius – will be needed.
“It’s not a simple swap out of technology, we have to almost start again with the aircraft design,” he explains. Airbus last year revealed three hydrogen-powered concept planes, all taking different engineering approaches.
Any new technology adopted will need to be commercialised and – importantly - universally trusted.
“Everyone is used to operating with kerosene-powered planes. There needs to be a level of technological maturity and driving costs down before equipment manufacturers, airlines – and the public – will accept change, both technologically and cost-wise, which is why we need to act now to address the carbon challenge,” says Howard.
The global aviation industry is expected to be worth around £4tn by 2050. Yet in April the UK industry raised alarm after the ATI, which allocates government money to the sector, was forced to suspend its funding programme for 2021.
With so much investment and transformation required, a key question remains: will it make flying more expensive for the masses? “That’s what our modelling currently foresees,” say Peerlings. “Though it’s possible companies might decide to internalise some of those costs.”
Ultimately, to achieve these ambitious goals, governments must create policy and provide funding streams to incentivise and support the necessary investments, agree Peerlings and Howard.
“By not doing this governments risk missing an opportunity to capitalise on the sustainable aviation market; it’s a global problem and a global industry, so there is a race to compete,” says Howard.