Could hydrogen-powered planes be the transport revolution the UK needs? The transport sector plays a significant role in reaching our net zero emissions in this country. Finding a greener way to travel won’t just help the UK reach its sustainability goals, but it could also boost the UK’s role in a worldwide transport revolution. Let’s take a closer look at the opportunities and possibilities that come from hydrogen-fuelled planes and what that could mean for the UK.
Aviation is responsible for 3.6% of greenhouse gas emissions in the EU. This is mainly because modern planes use kerosene for fuel, which releases carbon dioxide into the atmosphere when burned. Suppose the UK is going to achieve its zero emissions goals, with a possible target for domestic flights reaching net zero by 2040. In that case, the aviation industry needs a shake-up regarding its fuel.
There is a silver lining. It was highlighted in both the Aerospace Technology Institute’s FlyZero study and during Airbus’s 2022 technology summit that progress is being made in adopting hydrogen-powered planes. The R&D sector in aviation is working to incorporate hydrogen as a fuel in large aircraft, and we also see the potential for hydrogen combustion engines. Some even think we could be using hydrogen in planes by the mid-2030s.
Cranfield Aerospace Solutions works on a hydrogen-powered aircraft for Air New Zealand’s Mission Next Gen Aircraft programme. The program will focus on developing a smaller zero-emission aircraft that can be used for shorter routes, replacing the need for traditionally larger aircraft that have been used on such routes. It could usher in a new age of aviation.
With some challenging targets to decarbonise aviation in the UK, the road to reaching net zero for aircraft will be turbulent. Since safety is also paramount, different technologies will need to coexist until a complete switch to zero-carbon aviation can be reached.
Although we’ve seen the potential for hydrogen in long-distance transportation and hydrogen engines for vehicles, it’s a little more complicated in aviation. There is not much room for experimentation with new fuels in aviation due to safety concerns, not to mention the negative stigma of hydrogen being used for flight, thanks to associations with the Hindenburg disaster. However, the use of hydrogen in aircraft is closer than you may think.
Cranfield Aerospace Solutions are working on converting the propulsion system of a Britten-Norman Islander nine-seater aircraft to use gaseous hydrogen with a fuel-cell system. The goal is to have the plane run a commercial service for routes of up to 200 km by 2026. The exciting possibilities of using hydrogen as an alternative fuel in aviation can focus more on sub-regional air travel–catering to shorter domestic flights–which could cut emissions drastically for regional flights. Although France is tackling this issue by outright banning domestic flights and encouraging passengers to use high-speed trains instead, switching these short-haul flights to a hydrogen-powered system has the benefit of developing the technology to extend to long-distance flights, allowing for the technology to mature for larger aircraft.
Some countries in the world don’t have the option to take the French route, especially in areas that don’t have such a well-connected and efficient rail system. Some places view short-distance flights as a crucial building block for their community, particularly in more isolated areas.
If hydrogen can be used, that means planes would only emit water. It’s possible that large, long-distance hydrogen-powered planes could enter the market as soon as 2035. And some initial tests have found that hydrogen-powered planes can be just as fast as traditional planes, even carrying more than a hundred passengers over thousands of kilometres.
Hydrogen-powered planes would need to be slightly longer in length, and smaller planes would use propellers that use electric propulsion from hydrogen-powered fuel cells. On the other hand, larger planes would use hydrogen as a fuel source to power jet engines. They would require a storage system that can safely store hydrogen fuel, fuel cells to convert hydrogen to electricity, a device to control the cells’ power, and a motor to turn the propeller. These four areas must be developed sufficiently before these planes can operate commercially.
The leading countries that deliver sub-regional net-zero aircraft will have a strategic advantage over their competitors. The UK is leading the way with this technology with its research and implementation of Jet Zero Strategy. However, policy in the UK is also important, as it can drive innovation and create jobs and economic opportunities. If the UK can flatten the R&D curves of technologies and drive down costs, it could help make this green technology adoption easier globally and make a big dent in decarbonising the planet.
One such UK initiative is NAPKIN (New Aviation Propulsion Knowledge and Innovation Network), based out of Heathrow. The project aims to introduce regional and short-haul aircraft using hydrogen or electric propulsion. Heathrow has partnered with nine partners, including Cranfield Aerospace Solutions and Rolls-Royce, to work on the project. The project examines aircraft requirements and concepts for achieving net zero and also looks into the infrastructure needed in British airports to support more sustainable forms of aviation. The project takes a holistic approach going beyond aircraft technology, but also how to integrate it in a way that passengers will accept to figure out a workable blueprint for the introduction of zero carbon flights.
Although hydrogen as a fuel source has many advantages, several fundamental challenges can arise. One of the main ones is that hydrogen needs to be stored in the fuselage or external pods, as it requires greater volume when compared to kerosene. Although hydrogen weighs three times less, it takes up four times more volume. This means you’d need to build a large aircraft to hold the same fuel needed.
Catering to hydrogen-fueled planes means a new aircraft design, particularly since hydrogen has a much lower mass; the difference between the maximum take-off and landing weight would be much less than for kerosene-fueled planes. Also, there’s the elephant in the room in that hydrogen is flammable at certain temperatures and needs to be kept cold enough to prevent a disaster. You’d need an efficient cooling system to keep the aircraft safe.
It will be possible to have safe planes that can use hydrogen, but we may need to consider entirely new designs to cater to this, which will take time and research.
Introducing zero-emission aircraft into the UK will help revolutionise regional connectivity not just in the UK but also internationally. It will change how we fly altogether. NAPKIN believes that zero-carbon-emission flights on sub-regional routes with aircraft containing 7 to 19 seats will be feasible within a decade. Also, NAPKIN’s report found that it could even be cost-effective to replace the UK’s entire regional fleet with larger aircraft (50-90 seats) that are zero-carbon emission and safe by 2040.
The UK has the infrastructure in place, as many sub-regional airports could be resurrected to serve shorter flights and only require an upgrade. This could have a knock-on effect as it wouldn’t just serve as a local hydrogen-generation hub to power aircraft but also the airport and the surrounding community.
If the UK can show that hydrogen is the future for sustainable aviation, it’ll also make adoption easier on a global scale.