Flightpath to sustainability: How do aviation and shipping plan to hit “jet zero”?

With record-breaking heatwaves sweeping Europe this month, the effects of climate change are becoming a burning reality.

As parts of Europe hit record high temperatures, many eyes turned to the aviation and maritime sectors to reduce their polluting carbon emissions, with the UK government setting a target of net zero, or ‘Jet Zero’, for the industries by 2050.

Aviation, for example, is among the highest polluting sectors, with flights contributing around 2.1% of all human-induced carbon dioxide emissions. From such a high contribution, how can ships and planes hit such a reduction, especially when it’s notoriously difficult to both cut carbon and remain competitive?

Speaking at the Tech UK and Net Zero conference, Arnab Chatterjee, VP Infrastructure at zero-emission aviation company ZeroAvia; Lawton Green, strategic client partner aerospace and defence at engineering consultancy Quest Global; Anna Ziou, director of policy at UK chamber of shipping; and Gemma Beard, partner account manager at data firm Iotics, all cover how their industries are planning to hit net zero.

The panel stressed that cutting aviation and shipping carbon emissions is vital for the UK to achieve net zero, with the International Maritime Organisation expecting emissions to have halved by 2050, and aviation to have become fully net zero by the same year.

“Fundamentally, there is no other approach to net zero other than going to electrification,” says Chatterjee on aviation. Whilst regulatory challenges are stringent, he says decarbonising aviation in comparison to other industries is in some ways not as difficult.

Green agrees, adding that “the good news is that the same technologies that we are developing across all the sectors in which [Quest Global] operates are to some extent equally applicable to the aviation industry.”

“We can develop new technologies in different industries, such as automotive and rail, and we can share them back into aerospace.”

For shipping, the industry itself is economically huge and “the most efficient mode of transport to carry goods,” according to Ziou.

Ships carry 95% of goods that are imported and exported from the UK and also carry 80% of global trade, which is something Ziou blames for the initial oversight of taking maritime to net zero.

Fuel solutions

Both aviation and maritime are looking to hydrogen fuel cells, which essentially power vehicles through the chemical energy in hydrogen, to fuel their vessels and planes electronically.

For shipping, this is only an option for shorter voyages because it means the ships require frequent refuelling because of hydrogens low density, according to Ziou.

Inversely, aviation can use liquid hydrogen, which according to Chatterjee has a  densification of 300 times more than battery technology, which means that planes can run further on less. It’s also much more energy efficient.

Battery technology, for aviation, is a challenge as charging an entire plane takes an immense supply of power, says Chatterjee. In comparison, a Tesla will take about 100 kilowatts to charge, and a single depot of busses will take 20 to 60 megawatts. So when it comes to planes it will go above 100 megawatts, which is “talking a world scale unit, or a nuclear power plant.”

“So on the supply side there’s quite a lot of work going on,” to supply future demand, says Chatterjee.

Shipping and aviation are also looking at e-fuels and synthetic fuels, which can use existing infrastructure by turning electrical power to liquid, or power to gas.

However, according to Chatterjee, the technology to create these fuels has been slow because it’s “actually quite hard work,” and synthetic fuels are still at less than 0.5% of overall fuel today.

Green is most optimistic about the use of an eco-friendly fuel called kerosene: “At present, there is no better way of getting from A to B on a long haul aircraft than by using a kerosene fuelled gas turbine.”

“All of the infrastructure exists, and everyone’s already invested in that infrastructure to develop the fuel, but these industries are still in incubation stages that need to be fostered until they become self-sustaining.”

Additionally, for shipping, nuclear-run vessels are a completely zero-emission solution and are apparently on the radar as well.

Air bubbles are also a new technology that can improve the energy efficiency of vessels by allowing vessels to move more efficiently through water, as well as other assistive technologies such as new propellers, and new types of paint, according to Ziou.

Equipping and refuelling sustainably 

Typically, according to Ziou and Chatterjee, aircrafts today have a lifetime of 15 to 20 years, and ships have about 20-30 years.

“If we wait for that replacement cycle to happen for the 20,000 aircraft, and a fleet of 40,000 by 2040, we’re not going to hit our global 1.5-degree targets,” says Chatterjee.

So the solution is to equip, or retrofit, current models “whilst simultaneously looking at new developments,” and infrastructure to support new technology.

Today, 3% of airports are used for 97% of flights, which leaves ample opportunity for hydrogen hubs, or ‘Hydrogen Airport Refueling Ecosystems’ (HARE) for ZeroAvia.

“Hydrogen hubs allow these sectors to couple between the power sector and the heavy-duty mobility maritime sector, and indeed aviation,” to fuel up on hydrogen in the same place.

Chatterjee says in his previous work, they built “the first three heavy duty hydrogen stations at the port of LA, so we know that these ports want to do things like that.”

ZeroAvia is also currently ground testing its ZA600 powertrain, which will retrofit onto a plane, at it’s research facility at the Cotswold Airport in the UK. It is part of its program to demonstrate hydrogen-electric flight in a Dornier 228 plane.

Last October, it successfully tested a hydrogen-powered powertrain on a military truck and plans to test a bigger version of it for a 40-80 seat aircraft.

Ziou also said that the shipping industry is working with the UK government to invest in “shore power” and provide electricity to ships when they are docked.

Ultimately, Beard stressed to the industry that it didn’t “need to get distracted by the fact [it] needs to fix a global problem. We just need to crack on and every step towards net zero is a step in the right direction.”

“I think we’ve got the power to start where we are today. The technology is there, the commitment and appetite are there within the industry. We just need to get started with these small projects and let the global conversation happen where it happens.”