Montreal-based aviation research company Unither Bioelectronics is betting hydrogen is the future of sustainable fight, a prediction it is aiming to realize with a hydrogen and battery-powered helicopter it is developing.

In late March, a Robinson R44 Raven II, refitted to be powered by a hybrid hydrogen fuel cell and battery system, took flight for three minutes and 16 seconds at Roland-Désourdy Airport in Bromont, Que.

The proof of concept met Unither’s expectations and provided the bedrock for future tests, Mikael Cardinal, the vice-president of program management in organ delivery systems, told Sustainable Biz Canada.

The plan is to further examine the possibility of carrying payloads longer distances, and show the potential for hydrogen as a viable option for greener flights.

“I think for truly zero-emission flight, operationally speaking, it’s a consensus among the industry members that hydrogen has to be part of the solution,” he said.

Developing hydrogen-powered helicopters

A pre-commercial subsidiary of U.S. biotechnology company United Therapeutics Corporation (UTHR-Q), Unither is dedicated to developing low- to zero-carbon aviation to rapidly transport organs for transplant. Its test aircraft includes a battery-powered helicopter and a last-mile delivery drone.

Hydrogen-powered helicopters are Unither’s current priority, Cardinal said, a pivot it made 18 months ago by exploring hybrid-powered systems.

The energy density of hydrogen is an advantage compared to using an equivalent amount of batteries, which are significantly heavier by comparison. Plus, hydrogen holds about 2.5 times more energy per kilogram than kerosene, the International Air Transport Association says in a fact sheet.

“When you look at the anticipated improvement in fuel cell technology in terms of weight and also on the hydrogen storage systems,” Cardinal said, “we believe that the upside potential for that kind of technology is far beyond what even batteries could offer us even in 10, 15 years down the line.”

Two fuel cells powered by green hydrogen that provided approximately 90 per cent of the energy for the test flight were combined with a small battery pack. The hydrogen fuel was produced by splitting water with electricity from renewable energy, sourced just 30 minutes away from Unither’s research and development facility.

The zero-carbon test flight can reach approximately 30 minutes of time using gaseous storage.

For its next step, Unither is aiming for 200 nautical miles of range carrying a 225-kilogram payload using a Robinson R66. A weight-efficient liquid hydrogen storage system and next-generation fuel cell technology will be utilized for this phase of the testing, Cardinal said.

The ultimate aspiration is to design a helicopter that can travel 250 nautical miles with a 275-kilogram payload.

Hydrogen could become a preferred flight fuel

Hydrogen is frequently listed as one of the top solutions to reduce the greenhouse gas emissions from aviation. The sector is responsible for 2.5 per cent of global energy-related carbon dioxide emissions according to the International Energy Agency.

Compared to sustainable aviation fuel, another commonly named solution, Cardinal said hydrogen offers higher energy density and greater carbon reductions.

The hydrogen industry is nascent, so the infrastructure remains sparse. However, Unither does not see the lack of fuelling stations as a problem for the company.

Its helicopters require substantially less hydrogen than a large airline jet; approximately 20 kilograms of hydrogen can power its helicopters for 200 nautical miles of flight, Cardinal explained. Unither’s fuel needs could be met with a mobile liquid hydrogen production hub.

Safety has also emerged as a critical issue for hydrogen-powered flight. Hydrogen is highly flammable, which has led to safety concerns for aviation applications. Cardinal argues proper engineering can mitigate these hazards, pointing to features such as the fuel being ventilated faster than kerosene-based jet fuel.

“People think about Hindenburg. This is not Hindenburg at all,” he said, referring to a deadly 1937 disaster involving a hydrogen-filled German airship (blimp), which caught fire and crashed as it prepared to dock at a tower in New Jersey.

Though there have are signs the hydrogen industry has hit a snag because of the high cost of developing the infrastructure, Cardinal said the “hydrogen economy will develop, it’s a matter of when.”

Unither's next steps toward commercialization

To reach commercialization, Cardinal said Unither’s products will need to be certified by the government, which the company plans to pursue with a supplemental type certification with Transport Canada.

Unither’s work could evolve into other hydrogen-powered aircraft, he added, particularly airframes that can hover and take to the air without the need to accelerate on a runway.

Another improvement it is working toward is transitioning the storage system to liquid hydrogen, which would quadruple the flight time.