Aviation industry plotting a course to net zero
Project Napkin, the UK’s blueprint to achieve “guilt-free flying”, plans a new fleet of hydrogen jets by 2035, writes Oliver Gill
The fallout from the Hindenburg disaster has cast an 85-year-old shadow over the aviation industry’s plans to use hydrogen fuels. Shortly before 7.30pm on May 6 1937, the Zeppelin airship burst into flames killing 36 people as it attempted to dock in New Jersey. The television footage of the fireball, coupled with journalist Herbert Morrison’s commentary, helped cement hydrogen’s reputation as a dangerous fuel.
But this stigma baffles those that believe it is the answer to weaning air travel off fossil fuels.
“Kerosene [ jet fuel] is also extremely dangerous. And hydrogen is no less or more dangerous. It’s just different,” says Jenny Kavanagh, chief strategy officer at Cranfield Aerospace Solutions.
“The flames of the Hindenburg disaster were all about the canopy,” she adds. “The hydrogen was gone before the photographer turned up.”
Kavanagh is among a group of British scientists involved in a governmentbacked initiative codenamed Project Napkin, which has plotted a course to providing Britain with net-zero flights.
The Napkin blueprint, seen by The Sunday Telegraph, has been developed by a coalition of industry experts from the likes of Cranfield Aerospace, Rolls-Royce, GKN and Heathrow airport, as well as academics from University College London and Southampton University.
According to Napkin, hydrogen flights carrying up to 19 passengers between the Scottish islands and the mainland could be a reality between 2025 and 2030. These early flights will be operated by retrofitted planes carrying gaseous hydrogen in tanks beneath their wings.
From 2035, a new fleet of aircraft designed specifically to run on hydrogen could fly the domestic schedule from regional airports such as London City, according to the blueprint, which will be unveiled at the UN’s Cop27 climate change conference in Egypt this week.
And by 2040, 90-seater hydrogenpowered jets are scheduled to be in service, meaning the entire UK domestic aviation market will be operated by zero-emissions planes.
The plans pour cold water on electric-powered aircraft playing a central role “guilt-free flying” – this despite airlines such as easyJet previously identifying electric as the answer to reducing the industry’s carbon footprint.
“Hydrogen aircraft represent a credible solution to reach zero-carbon flight and are the natural complement to sustainable aviation fuels,” the blueprint says. “While other solutions were looked at initially, such as electric and hybrid propulsion, the consortium concluded that hydrogen technologies provide the path to zero-carbon emission flight for mainstream commercial services.”
Airlines have been blamed for their role in the climate crisis as activists such as Greta Thunberg campaign against the industry through the flygskam, or flight-shame, movement.
Between 2pc and 3pc of carbon emissions are generated by the global aviation industry. But in the UK, as other sectors reduce their footprint and air travel continues to grow, the industry is on course to produce 39pc of greenhouse gas emissions by 2050.
Those involved with Napkin say their proposals will form the basis of the UK’s answer to decarbonising air travel, in the same way that similar governmentcommissioned reports provided the framework for the ban on the sale of petrol and diesel cars by 2030.
The hydrogen-powered planes envisaged to be in the skies above Britain from 2025 are little more than a stepping stone. Initially, hydrogen will be used in gaseous form.
“Compare hydrogen with kerosene, it has three times the amount of energy,” explains Kavanagh. “It’s a really powerful energy, which is why it’s so exciting.” But there is a snag. In volume terms, per cubic foot, it is less powerful than kerosene. The answer is to load the hydrogen into highly pressurised tanks. “It makes those tanks very heavy. So you can only really do it on small craft.”
The answer is to liquefy the hydrogen. This is where the new planes are being designed – rather than retrofitted as is the case with the first flights – ready to be in service by 2035.
Liquefied hydrogen is not without its challenges, however. Kavanagh explains: “It still takes up more room than the normal kerosene, because it has to be kept at minus 273C in cryogenically insulated tanks, so you can’t stick them in the wings like you do with normal kerosene.” This is just one of myriad hurdles that need to be overcome in the coming years, experts say. Another is ensuring that the aviation industry is able to access the quantities of hydrogen that it will need.
“Total demand for green hydrogen is going to be an enormous challenge,” says Nick Goss, a project engineer at GKN. He explains that under Napkin’s baseline scenario, demand for hydrogen will exceed the installed capacity for the whole of the UK.
“If you just took aviation and aerospace, you’ve already not got enough green hydrogen being produced,” he says.
Among the other considerations is the cost of hydrogen. Commercial airlines have little desire to increase their fuel costs despite the environmental benefits.
The Napkin report concludes: “The price of liquid hydrogen relative to fossil kerosene is a critical factor in determining profit-optimal uptake of ZEF [zero-emission fuels] by airline operators.” The analysis continues that if hydrogen prices fall to $1/kg, “ZEF uptake could cover almost 100pc of the UK domestic market. This could fall away to very little if hydrogen prices remain closer to present day values”.
A further restraining factor relates to the distribution infrastructure. The experts envisage that until the mid2030s, most of the hydrogen will be transported to airports by truck.
If airports had to continue bringing hydrogen in by lorry, by 2050, large bases like Heathrow would need 334 truckloads a day, equivalent to one lorry every four to five minutes.
Britain’s “guilt-free flying blueprint” is not designed to tackle long-haul flights. The assumption is that in the medium term, flights to Asia or America will increasingly run on sustainable aviation fuel. But that is not to say that the technologies being developed for smaller aircraft will not be relevant for larger ones. Matt Gorman, director of sustainability at Heathrow, says: “You start small, and you scale up. You learn so much from the small initial aircraft, doing the island-hopping [services].
“Confidence grows, you learn about regulation and compliance. And you get all of those crunchy bits sorted out before you get to the larger aircraft.”
Japan has long held the lead in the development of a hydrogen economy. But momentum has grown in the UK. Could Britain at least be the leader in hydrogen-power aircraft if ministers heed to the advice of their experts?
“It’s difficult to tell who’s ahead,” says Kavanagh. “It’s like asking who is winning in the middle of a game of cricket. It’s impossible to tell. We don’t know what’s going to happen.”
Gorman adds: “We’ve got time to get this right. But we can’t sit on our hands because otherwise we’re just going to fall behind.”