• 17 Apr 2024 11:34 PM
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3rd Annual H2-Aero Symposium

By Dan Gettinger, Managing Editor
Vertiflite, May/June 2024

Hydrogen aerospace gets real in 2024 with industry and government working together towards sharing the latest developments from technical to certification and the pathway towards commercialization within 10 years.

The 3rd Annual H2-Aero Symposium, the Vertical Flight Society’s premier meeting on hydrogen aviation, occurred on March 13–14 in Charlotte, North Carolina. Previously a stand-alone event, this year’s H2-Aero Symposium was co-located with SAE International’s AeroTech Conference. As always, H2-Aero sought to harness the latest technical advancements and progress on policy, standards and regulations. This year, there was also a focus on government support for hydrogen as a direct fuel source, in addition to the push for e-fuels or sustainable aviation fuel (SAF) to accelerate the decarbonization of the transportation sector. Carbon-neutral electrofuels (e-fuels) are manufactured using captured CO or CO2, together with hydrogen obtained from water, split by sustainable electricity.

The 3rd H2-Aero was packed with presentations on the latest developments in hydrogen aviation. Organized with support from the VFS H2-Aero Team — which VFS formed in 2022 and is chaired by Jesse Schneider, CEO of ZEV Station — the symposium featured leaders from across the global hydrogen aviation and fuel cell community over the course of a day and a half in six sessions.

The following represents a summary of the wide-ranging event and includes excerpts from each of the in-depth sessions. Video recordings of the entire event are available to all VFS members and symposium attendees for free and may also be purchased at the VFS Vertical Flight Library. For more information about the VFS H2-Aero Symposium, visit www.vtol.org/h2symposium.

Progress and Innovations

The first session of the symposium addressed progress in developing hydrogen-powered aircraft. Chaired by VFS Director of Strategy Mike Hirschberg, the panel included remarks by Bill Spellane, Chief Operating Officer (COO) of Alaka’i Technologies; John Scott, Piasecki Aircraft Corporation’s PA-890 Program Manager; and Jérôme Mora, Safran Innovation’s H2Tech Program Director.

Spellane gave insights into the technical development and flight testing of the Alaka’I Skai demonstrators, which have flown with both gaseous and liquid hydrogen.

Piasecki Aircraft is stepping up its plans to bring its hydrogen fuel cell-powered PA-890 helicopter to market by the end of the decade. Development work, which has been significantly boosted by support from the US Air Force, now involves the evolution of a 660-kW test rig for the propulsion system into an iron bird that will pave the way for a full-scale prototype the company aims to start flying in 2028. The PA-890 slowed-rotor, winged compound helicopter is expected to be able to carry a pilot and up to seven passengers on trips longer than 200 nm (370 km). “We’ve made some significant progress and what we’re striving towards is to increase the energy density available for vertical flight by around five times compared with batteries,” said Scott.

Safran, meanwhile, is working on all aspects of hydrogen propulsion systems, Mora explained. “We don’t just look at the fuel cells or the turbine, but also to the complete chain with the fuel systems between the tank and the fuel cell or the turbine,” he said. Certifying these systems will require doing the same tests on hydrogen propulsion systems as the company does on kerosene engines.

The second panel of the meeting addressed innovations in hydrogen aerospace propulsion. This panel included presentations by session chair Paul Gloyer, CEO of Gloyer-Taylor Laboratories Inc.; Prof. Philip Ansell, Assistant Professor at the University of Illinois; and Dr. Vadim Lvovich, the H2 Aircraft Technology Lead at NASA’s Glenn Research Center.

Gloyer discussed a recent breakthrough achieved by Gloyer-Taylor Laboratories (GLT) in validating an ultralight cryotank. The company’s ultralight tanks allow 10 times more hydrogen fuel than conventional, state-of-the-art storage technology, Gloyer said. Using its composite liquid hydrogen Dewar tank, GLT is working on developing a long-endurance drone technology demonstrator, flight demonstrations of which are planned for 2024, as well as the Wrangler heavy-lift drone with 10–12 hours of flight time. Gloyer also provided thoughts on a conceptual retrofit of a 737 Max 8 with liquid hydrogen tanks.

Regarding cryogenic tanks for hydrogen, Lvovich observed that the major challenge is not only that they must be lightweight, but also that they are able to survive thousands of pressure temperature cycles. “That particular expectation is fairly standard for terrestrial materials, but it is new for aeronautical applications,” said Lvovich, who added that NASA’s cryogenic tanks for hydrogen storage for space missions are typically designed with one cycle in mind. Lvovich and Ansell — who presented conceptual work on hybrid hydrogen airliners — agreed on the need to invest in the development of a national testing capability for hydrogen that is multidisciplinary and multimodal. Lvovich also presented NASA’s vision towards technologies needed for commercial aviation to 2050 to replace powertrains and storage.

Powertrains and Government Support

The morning of the second day kicked off with a session addressing hydrogen fuel cell powertrains. ZEV Station’s Schneider served as the session chair and introduced the topic. The panel featured presentations by Jos Stonham, GKN Aerospace, and Todd Solomon, ZeroAvia.

GKN has sought to look comprehensively at the hydrogen system with programs like H2GEAR, which aims to develop the hydrogen fuel cell propulsion system, and HyFIVE, a liquid hydrogen fuel system. Despite tangible opportunities in the short-range regional air mobility market in the near term, “the focus for GKN really comes in the next decade — 2030 to 2040 — where we see an actually viable aircraft in the order of 2,000 km [1,100 nm] of range being achieved,” said Stonham. “It requires a blank sheet design to really integrate the hydrogen system… onto that aircraft.” The areas that require greater attention from researchers, however, include synergetic heat dissipation, fuel cell systems and components, which must be integrated into a flying technology demonstrator.

Solomon spoke of ZeroAvia’s pioneering plans with fuel cell powertrains in aerospace, starting with smaller, nine-seater aircraft, growing to regional aircraft by 2030 and to a 200 seater by 2040. ZeroAvia currently has 400-kW fuel cell modules and innovative balance of plant components related to scalable fuel cell compressors, inverters and electric motors.

Session four of H2-Aero addressed issues involving government regulation and hydrogen hubs. The panel featured presentations by Peter Devlin, US Department of Energy (DoE); Roxana Bekemohammadi, US Hydrogen Alliance; and Dr. Monterey Gardiner of the National Renewable Energy Laboratory (NREL), who also served as the session chair. Schneider and Solomon gave an overview of the California Alliance for Renewable Clean Hydrogen Energy Systems (ARCHES) aerospace whitepaper for Shruti Sarode of the University of California, Berkeley, who was unable to attend.

Devlin gave an overview of the DoE’s hydrogen hubs, with a total of $7B to be funded to seven awardees. He indicated that at least two of the hydrogen hubs, California and Pacific Northwest, are considering hydrogen aviation. He observed that hydrogen today has the “highest visibility ever in terms of leadership support in the government,” with support coming not only from the White House but from across the federal government. This support has resulted in initiatives like the Hydrogen Interagency Task Force (HIT), a whole-of-government approach dedicated to meeting the objectives in the US National Clean Hydrogen Strategy and Roadmap. The HIT working groups are addressing issues like electrical grid support for hydrogen production and the possibility of exporting hydrogen.

The seven regional clean hydrogen hubs, which the DOE announced on Oct. 13, 2023, represent the beginning of a concerted effort to realize the potential for hydrogen in decarbonizing the transportation industry. “We start with regional networks, but eventually we want a national network,” said Gardiner from NREL. “This is a long effort, and we have to keep moving now; we can’t wait four or five years for [the hydrogen hubs] to be put into the ground and commissioned.”

Standardization

The second afternoon began with a session that addressed hydrogen standardization. The session featured presentations by Mike Walz, US Federal Aviation Administration; Dr. Linda Brussaard, European Union Aviation Safety Agency (EASA); Jesse Schneider, ZEV Station; Olivier Savin, CEO of French hydrogen aircraft start-up Blue Spirit Aero; and Anirudh Vyas of the UK Civil Aviation Authority, who also served as the session chair.

Walz and Brussaard stressed the need for regulators to work with industry to develop standards for certification and, above all, to address safety risks. “We need you to coordinate and collaborate with us,” said Brussaard. Olivier Savin addressed the work of two working groups, the joint SAE AE-7F, hydrogen storage and fuel cell group and the joint activity with EUROCAE WG-80.

Jesse Schneider gave an overview of SAE AE-5CH Hydrogen Airport Taskgroup. In the coming months, SAE aims to publish its first guideline, AIR 8466, which aims to specify the high-level general requirements for hydrogen fueling stations, both gaseous and liquid hydrogen, at airports. A new topic that was presented was regarding hydrogen fueling categories; for regional aircraft, this would be between 880 lb (700 kg) and 4,400 lb (2 t) of hydrogen. This means that even a small number of this type of aircraft would require significantly more hydrogen than ground transportation and necessitate significant supply from a hydrogen hub.

The final session of H2-Aero addressed hydrogen and fuel cell research and development. The session featured presentations by Dr. Jason Damazo, Director of the Boeing Shock Physics Lab, and Matt Hortop of AVL, who also served as the session chair.

AVL is supporting the German Aerospace Center’s (DLR) BALIS project, which aims to provide the means to test the components of a hydrogen fuel cell propulsion system under real load cycles. Beyond BALIS, AVL is providing battery test systems for the electric vertical takeoff and landing (eVTOL) aircraft developer Lilium and developing a high-altitude fuel cell system testing.

Damazo, meanwhile, addressed the risks of fire with hydrogen leaks. “When we think about regulating commercial aerospace for using liquid hydrogen… what is much more important than looking at ignition sources is looking at flammability, and building equipment that doesn’t allow for the leak of fuel,” said Damazo. There was an in-depth discussion on hydrogen safety where many lessons could be learned from fuel cell ground vehicle crash testing and safety standards. The group agreed that the standards for the aircraft and hydrogen fueling both need to have a high level of confidence based upon an aerospace specific risk assessment.

Major Activities

At the end of the H2-Aero Symposium, Schneider underscored the successful flights in hydrogen aviation since 2023, similar to the Wright Brothers’ flight 120 years ago in North Carolina. He also indicated the success of the H2-Aero “Multimodal H2-Airport Hub” whitepaper and its influence it has had on the California ARCHES Hydrogen Hub. He underscored that the members of the H2-Aero Symposium played a key role in this success, but there is “a lot more to do towards hydrogen commercial aviation.”

As he does each year, Schneider closed the symposium asking the members what they thought the “heavy hitter” goals were to address before the 2025 H2-Aero conference. The following were indicated to be the highest priorities:

1. Start an effort related to developing training materials in hydrogen safety/fuel cells, etc. (and/or leverage existing) for first responders and maintenance personnel.
2. Develop a common liquid hydrogen coupling specification for regional aircraft, up to 175 lb/min (80 kg/min) filling up to 4,400 lb (2,000 kg) of hydrogen.
3. Work with regional hydrogen hubs such as California and Pacific Northwest towards developing hydrogen demand approximations.

The 4th Annual H2-Aero Symposium is planned for March 2025, and will return to Long Beach as a standalone VFS event once again. More information on VFS hydrogen initiatives, and the H2-Aero whitepaper, can be found at www.vtol.org/hydrogen.