The first word that may come to mind when seeing hydrogen and air travel in the same sentence is Hindenburg. Future generations, however, may think of sustainability when they hear the words hydrogen and aviation in the same breath. The April 7th, 2020 webinar, “Powertrains for the air transportation market: Hydrogen vs. Lithium – what’s better,” made a strong argument for hydrogen as a fuel for future aircraft.
In today’s world, hydrogen won’t be used as the lift mechanism, like it was for the 1930s era dirigibles. It will be the fuel that, silently and without emitting pollution, creates electricity to power various types of aircraft. Back to the 50,000-foot level and why hydrogen may help aviation rebound from the great COVID-19 crash of 2020 and respond to concerns regarding C02 emissions.
Hydrogen Needs Aviation and Vice Versa #
Valery Miftakhov, Founder and CEO of ZeroAvia, painted a picture of the importance of hydrogen to aviation and vice versa when he stated that those working on hydrogen fuel cells should,
“Focus on aviation as the killer app for hydrogen.”
In as many words, Miftakhov is suggesting that, in order to fly through the metaphorical headwinds from air travel-caused carbon emissions, hydrogen is essential for electrifying the aviation fleet.*
ZeroAvia’s near-term focus is retrofitting existing aircraft with their hydrogen fuel cell drive trains. Miftakhov projects commercial implementation of their power trains in 10 to 20 passenger, fixed-wing commuter planes by 2023. According to Miftakhov, these existing aircraft will achieve a 300 to 500-mile range and improve the economics of regional air travel.
Miftakhov indicates that the upfront capital cost of a hydrogen power train is already comparable to a turbine. The real advantage, besides zero emissions, is that the ZeroAvia’s powertrain promises up to a 75% lower operating and maintenance cost compared to a comparable turbine. In turn, ZeroAvia estimates this could translate into a 50% reduction in total trip cost.
Advantages to Hydrogen for Electric Aviation #
Being an electric drive-train, the hydrogen fuel-cell is about 1/100 the noise level of a state-of-the-art helicopter, according to John Hamilton of JNLCorp. To put this in perspective, Hamilton said that Joby Aviation’s electric aircraft emits about the same noise as a passing Prius.
As a pilot, and former staff engineer for Joby Aviation, NASA JPL, and the US Naval Postgraduate School, Hamilton has a good understanding of the future of aircraft design. He stressed not to fear the volatility of hydrogen as the packaging of the fuel cells will survive greater G-force crashes than what passengers could sustain.
Speaking of packaging, HyPoint is developing the hydrogen fuel cell system used by ZeroAvia and others. From an energy-density perspective, HyPoint is already achieving 1,000 Watt-hour/kg, which is 2 to 3 times better than the best batteries available today. According to a HyPoint whitepaper, the specific energy of hydrogen is more than 200 times greater than lithium batteries (120 MJ/kg versus 0.65 MJ/kg). The bottom line is that HyPoint is aiming for 20 kW to 300 kW power plants that can provide 90 to 240 minutes of flight time.
Ilya Khanykov, the CEO of Bartini suggests that hydrogen fuel cells have many advantages over battery-electric and turbine electric, including:
- Longer range than pure electric
- Quick “recharge”, compared to electric, allowing for great aircraft utilization
- The advantages of an electric drive train (low-noise, zero tailpipe pollutants)
Existing Airfields as a Catalyst #
Existing airfields could be the catalyst for the hydrogen fuel cell market to lift off, according to Arwed Neistroj, CEO of solid-state battery inventor, KeraCel. He points out that fuel cells need a complete ecosystem. Existing airports could be the hub for such an ecosystem. The aviation use-case presents fewer distribution points for hydrogen, as compared to, say the automobile market, which will make it easier to scale.
The air transportation network can take advantage of the attributes of hydrogen fuel cells to create a point-to-point, regional mesh network that off-loads traffic from existing major airports. Surf Air, which today uses piston-based aircraft, is an example of the new type of air transportation services that will make up such a network. With its lower operating costs and reduced negative externalities (lower noise and pollution), electric aviation offers the promise of scale for these nascent services.
Electric Aviation Could Change Urban and Rural Communities #
Khanykov spoke about the McFly.aero initiative which aims to help cities adapt to this new approach. McFly.aero’s mission has striking similarities to CAMI (see this Viodi interview). Both organizations are looking at the problem holistically and from a community-basis. McFly.aero seems to be more of a commercial venture, compared to CAMI. The promotional copy for the webinar described McFly.aero as, “A property management and technology integration company for the Urban Electric Air Mobility industry.”
And, the economics of electric aviation that these speakers spoke of could rejuvenate existing and stimulate the creation of new communities in rural areas. For a thumbnail of the economics of how this might work, check out this interview with Bye Aerospace’s CEO, George Bye.
With a growing effort to electrify air travel and its favorable economics, the sky seems to be the limit for hydrogen fuel cell drive trains in the air transportation industry.
*Mifitakhov suggests that, with no improvements, aviation’s carbon emissions will grow from 2.5% today to between 10 to 25% of total emissions by 2050. Part of this relative growth is due to declining emissions in other sectors.