“We see a lot of runway!”

Whether or not the pun was intended, one thing was certain: the excitement and optimism the panelists exuded as they gave their views on the possibilities and adoption of green fuels in FlightGlobal’s webinar: “Hydrogen and electrics, the great disruptive propulsion debate”, were virtually tangible (now that oxymoron pun was intended!). The question now is simply, how long will we be taxiing to that runway?

Moderated by FlightGlobal’s Contributing Editor, Mark Pilling, the panel consisted of Josef Kallo, Co-Founder and CEO of H2FLY, Andreas Aks, Chief Executive of Wideroe Zero, Nikhil Sachdeva, Global Lead for Sustainable Aviation at Roland Berger, and Dr. Michael Winter, Senior Fellow, Advanced Technology at Pratt & Whitney.

It's all about power
“We’d be forgiven for believing [that hydrogen] is already the solution. It's in our grasp, it's here!” Mark Pilling introduced the discussion topic. “We're gonna talk about that, but there are power choices. We've got electric, we've got hybrid electric. We've got hydrogen. And, of course, there's a faithful gas turbine. We're not going to forget about that; Michael won't let us forget about that, and nor should we. Our job is to examine all these choices.” On the flight path to zero emissions by 2050, the key to success for the aviation industry, is in its engines.

Let’s hear it for the jet engine!
Dr. Michael Winter opened with a laudation to the jet engine, and voiced what perhaps falls into the shadows when people talk about alternative fuels and cleaner skies – the fact that traditional jet engines are also continuously developing: “Since the dawn of the jet age, the gas turbine engine has improved by about 1% or 1.5%, year over year. And we see a lot of runway for that to continue,” he said, illustrating the introduction of the geared turbofan engine in 2016 as one such success. Much is being invested and done to improve bypass ratios, propulsive efficiency, and thermal efficiency, he continued, pointing out that “we see huge opportunities, we see new classes of material systems”. With regard to SAF, too, he underlined that the geared turbo fan engine, “when it enters service in 2024, will be capable of 100% SAF”, since this has already been trialed since MAR22, following more than 15 years of SAF burn tests.

“A sweet spot in the market”
Moving on to electrification, he points to “a sweet spot in the market” and urban air mobility as the starting point, since it “is enabled by about half a megawatt per megawatt, occasionally, a few passengers, a few kilometers. Those technologies exist!” A turboprop project is in place with the Canadian Government, looking to launch flights in 2024 that are 30% more efficient the traditional turboprops. Andreas Aks shared Josef Kallo’s excitement about electrical planes, pointing to the all-electric Pipistrel and the fact that electric planes have “more torque and are even better than any conventional plane I have flown!”. They also keep their efficiency throughout the flight, whereas jet engines do not. Norway, with 99% green electricity, is an excellent testbed for electric aviation, he said.

Give us the gas on hydrogen
H2FLY’s Josef Kallo spoke for hydrogen-electric flight: “So, first of all, as German engineers, we do not talk too much we do things and realize things,” and described H2FLY’s successful demonstrations since 2014. “Hydrogen-electric propulsion will have challenges regarding upscaling, and so on, but we do not see no-gos regarding the technology.” The hydrogen steam turbine engine could be up to 35% more efficient than today's best turbofan, and its impact and any contrails will be much smaller than those of conventional aircraft, and will generate zero CO2, across the whole chain of production, storage, and usage. “We can be competitive on the middle-range: 4,000 km, with maybe 60-80 passengers,” he was confident.

The enormity of the challenge
Nikhil Sachdeva’s view was more sobering: “We, as consultants, we have to really think about the entire ecosystem and the entire challenge being faced by the aviation sector is really massive.” While on the one hand, the public discussions about decarbonization were positive, on the other hand, what was not being sufficiently looked at were, for example, the non-CO2 effects – mentioning (little-examined) contrails, taxation (non-conform, and not being put back into aviation), the will to support expensive transition, and the required scale and supply network of SAF, for example, since aviation competes with many other industries pursuing the use of hydrogen in their operations. His two-fold summary was: “So, we need all this innovation, and we need it at every part of the [aviation] value chain […]. Ultimately, it comes down, strangely enough, to cost.” Those costs require investors, and today’s investors want quick returns, which aviation transition cannot offer.
 
Is hub-and-spoke dying?
The entire scope of aviation needs rethinking, since greener fuels work in smaller aircraft – so perhaps the days of hub-and-spoke networks are numbered, and the future lies in point-to-point. Either way, an entire infrastructure of fuel production and delivery needs setting up. Nikhil Sachdeva recalled Thomas Edison inventing the light bulb as a comparable situation: “When he invented light bulb, he had to invent the entire electrical grid to be able to sell his light bulb […] he had to create the rest of the value chain.” All panelists were clear and optimistic that a change in aviation is coming, compared to what we have today.

Don’t do a little here, a little there – Focus!
“My personal opinion as an engineer, but also as a human being on this on this planet: We do not have 50 years from now, to do business as usual […] if we really want to do a change, we have to do it in the next 20 years,” Josef Kallo warned, emphasizing: “As aviators, we have to bring our energy source, our storage, and our usage with the right technology.” That means going for a system that can deliver renewable energy, which can then be combined with the highest efficiency fuel, and the highest efficiency technology.

We will be ready!
Dr Michael Winter pointed out the extortionate amounts of money going into oil and gas, today, and that “that money is all going to be spent on something over the next 28 years, and so we have an opportunity” going on to conclude: “We're really excited about the technologies starting with the gas turbine engine, moving through sustainable aviation fuels, embracing electrification, and ultimately, for hydrogen, that infrastructure will emerge and working across the industry […] we are going to develop those technologies and […] we are going to be ready!”

Brigitte Gledhill


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