Future of sustainable aviation is in the hands of refueling infrastructure. For the most part.
Aviation industry aspires for net-zero emissions by 2050. This is a challenging goal. Hydrogen has been gaining incredible traction from governments and industry, especially in Europe.
A recent study published by McKinsey concluded that short range (<165 passengers) and medium range (< 250 passengers) flights today account for two-thirds of current aircraft emissions. These are 70% of today’s global fleet, making them excellent platforms for meeting net-zero emissions goal.
Airbus forecasts more than 35,000 short and medium-range aircraft in will be operating in the next 20 years. While it isn’t yet clear how this forecast changes with disruption caused by COVID, this forecast number will still be around 20,000 – 30,000. The European aerospace industry have announced plans to demonstrate the next generation technology by late 2020s, with entry in-service by 2033 – 2035. Hydrogen is the top contenders alongside synfuels, biofuels and various electric-hybrid options.
Hydrogen-powered aircraft technology is a significant development challenge. For hydrogen-powered aircraft to be a success, challenges such as hydrogen embrittlement, storage and feed systems, and thermal management must be overcome. This will be part of hydrogen fuel cell and combustion technology development for aircraft.
Hydrogen fuel cell power-trains being developed for small commuter aircraft are the most obvious and sensible start for development – ZeroAvia is a great example of this. However, commuter aircraft aren’t going to help achieve the aviation’s net-zero emissions goal, and fuel cells are probably not the answer to short-range and medium range flights with a 100+ passengers.
If hydrogen is to succeed in aviation as fuel of the future, removing bottlenecks in high volume transportation and storage infrastructure is key. Airlines will be more willing to adopt these new aircraft type if the infrastructure is being developed extensively. If not, hydrogen will end up becoming nothing more than fuel for small commuter/regional size aircraft.
Gasoline cars wouldn’t be popular if gasoline refueling infrastructure wasn’t available. Same is true today for electric vehicle adoption, which requires a significant investment for developing the charging station network. Compared to hydrogen, alternative fuels such as synfuel and biofuel already have a head start, as these fuels are able to use existing storage and transportation infrastructure.
As aircraft operators, airlines (along with governments) will have a key role to play in developing the hydrogen supply chain. Let’s consider an airline planning to utilize hydrogen-powered aircraft for flying a specific route. It is obvious that both destinations on the route must have the necessary hydrogen refueling infrastructure. Other questions that are also just as important for route planning must also be answered, such as – will airports along the route within range for emergency landing or diversions have hydrogen refueling infrastructure? If not, is there an existing emergency supply source available by road transport? For a route to be viable and economical for an airline, these are just two of several dozen scenarios to be analyzed. Complexity in route planning means an increased risk and costs, which will be passed on to passengers.
Until now, there has been no fundamental change in fuels for aircraft other than those derived from fossil fuels. Alternate options such as fully-electric aircraft are not yet commercial and pose their own challenges. Jet fuel blends may have changed over time, but the overall handling qualities and operating requirements have been similar. Hydrogen is a vastly different fuel that Jet-A and its variants.
Technology development is just one small piece contributing towards making hydrogen-powered aircraft a reality. Infrastructure development is the key to successfully de-carbonise aviation and achieve the industry’s net-zero emissions goal. Technology comes a close second.
Adit Shah is an aerospace engineer with experience developing aircraft, UAVs, and space systems. He has previously worked at Airbus, Space Platform Technologies, and currently works at Prismatic Ltd. Adit also writes about aerospace and space technology at www.theaeroengineer.com.