According to the zero-emission flight innovator, early testing of its pressurised 20kW HTPEM stack power module at its UK R&D location has demonstrated 2.5kW/kg specific power at cell level, which it hopes will pave the way for 3+kW/kg system level densities in the next 24 months.

ZeroAvia believes this next generation of fuel cells could be sufficient to enable to electric propulsion systems for 100+ seat single-aisle turbofan aircraft such as he Boeing 737 and Airbus A320.

For large, fixed wing aircraft and rotor craft, ZeroAvia say it is necessary to increase the temperature and pressure within fuel cell stacks to offer a commercially viable products, as it allows for air cooling, cooling drag reduction, and system simplification.

The development of its HTPEM systems will support the company’s ZA2000 powertrain for 40-80 sear aircraft, as well as a range of rotorcraft and eVTOL applications.

H2 View understands the components used in the ZeroAvia system have been validated through third-party independent testing at several labs, including a US Department of Energy (DOE) national lab, which the firm believes confirms the potential for HTPEM systems to accelerate the development of large hydrogen-electric powertrains for large aircraft.

“The companies and geographies that seize the lead in high fuel cell temperatures and pressures will lead the industry,” said Val Miftakhov, CEO of ZeroAvia. “Hydrogen fuel cell propulsion is the most environmental and economical alternative to existing engines, and HTPEM is the most promising route to delivering these benefits into large aircraft categories.”

Miftakhov added, “I am confident that what we are demonstrating now is the core building block to delivering zero-emission flight for all categories of aircraft in the long-term.”

The HTPEM announced follows just weeks after ZeroAvia completed its first test flight of a 19-seat aircraft utilising low temperature PEM (LTPEM) fuel cell systems.

Read more: ZeroAvia records first flight powered by hydrogen-electric engine

Although the company says the LTPEM system worked well for the sub-megawatt scale aircraft, but the lower stack core temperatures make it harder to remove heat from larger systems.