The aviation industry has long been in a relentless pursuit of technological advancement, efficiency, and sustainability in propulsion. In a recent collaboration, Turbotech, Safran, and Air Liquide teamed up to validate the feasibility of using liquid hydrogen to power a turbine engine.
Nearly a year ago to this day on January 11, 2024, Safran and Turbotech successfully ground-tested a small TP-R90 turboprop engine – designed for two- to seven-seater airplanes – using hydrogen gas. It was part of the BeautHyFuel project, which is a collaboration of mostly aviation companies to explore the potential of using hydrogen for light aviation.
On January 13, 2025 – with support from the French Civil Aviation Authority – Turbotech, Safran, and Air Liquide (a company that specializes in advanced cryogenic hydrogen storage) successfully ground-tested a turbine engine fueled by liquid hydrogen. This marks the first time this type of fuel has been used in a turbine engine designed for the light aviation market.
The collaboration leverages each company's particular area of expertise. Turbotech specializes in ultra-efficient light turbine technologies; Safran has extensive experience in propulsion systems and fuel system designs; and Air Liquide focuses on hydrogen storage and handling management.
"This is a major step forward in the transition to fully decarbonized aircraft propulsion, which will be ready to fly as soon as the world mass-produces green hydrogen," said Damien Fauvet, CEO of Turbotech.
Hydrogen is often lauded as the clean alternative to fossil fuels. When burned at low temperatures, its only quantifiable emission is water. However, when burned at high temperatures upwards of 2,000 ºF (1,093 ºC), the nitrogen in the air reacts with the oxygen to create nitrogen oxides (NOx) – you know, that stuff that mixes with moisture in the air to create nitric acid, also known as "acid rain."
Hydrogen inherently has an extremely high flame temperature of up to ~5,500 ºF (3,038 ºC), ripe for creating NOx. It's possible to reduce the the amount of NOx created in combustion engines using cooling methods like water injection, staged combustion, running leaner (less fuel, more air) or simply using fuel that's been cooled down.
While burning hydrogen might not (yet?) be the "pure and perfect" solution, even at its dirtiest it's far cleaner than burning kerosene or gasoline, as hydrogen doesn't create CO2, soot, or other unburned hydrocarbons. It also has more energy than jet fuel (kerosene) by weight. Kerosene is around 12.0 kWh/kg whereas hydrogen is nearly triple that, upwards of 33.3 kWh/kg.
"We're proud to be involved in this project as a recognized expert in hydrogen technologies," said Xavier Traversac, VP of Air Liquide Advanced Technologies. "Hydrogen is one of the key elements in the energy transition – and this success is another step toward low-carbon flying."
In the long run, hydrogen is the cleaner and more sustainable route, especially as technology and infrastructure improve. Currently, hydrogen is expensive and difficult to handle. It requires specialized equipment and engines to make, store, and use. Liquid hydrogen requires even more specialized equipment, as it must be kept at or below -423 ºF (-253 ºC) to remain liquid.
The advantage of liquid hydrogen over its gaseous form is in storage. Even when stored at high pressure (10,150 psi/700 bar), hydrogen gas is still significantly less dense (and one might argue more dangerous) than liquid hydrogen – which istypically stored between 15-145 psi (1-10 bar) – allowing for more fuel within the same volume. And more fuel means more range.
"By coupling our technology to Air Liquide's cryogenic storage system, which provides the energy density needed for aircraft applications, we've demonstrated that a complete high-tech propulsion solution with zero carbon emissions in flight is possible and that it can be directly integrated into light aircraft," added Pierre-Alain Lambert, VP Hydrogen Programs, Safran.
We look forward to future flight tests.
Source: Safran Group
