Rolls-Royce Tests Hydrogen as Fuel in Gas Turbine Jet Engine

On a military site in England, a Rolls-Royce AE-2100A gas turbine jet engine — used in regional aircraft all over the world — is undergoing flight tests using hydrogen fuel for the first time, reported BBC News. The tests are being conducted in partnership with airline easyJet.

In the short term, the purpose of the tests is to demonstrate that jet engines can run on hydrogen power. The larger aim is for the use of hydrogen as a clean-burning fuel to grow, replacing fossil fuels and slashing greenhouse gas emissions.

“The reason we’re looking at hydrogen is really the drive for Net Zero,” explained Director of Aerospace Technology at Rolls-Royce Alan Newby, as BBC News reported. “Normally we would run this thing on kerosene. Kerosene is a hydrocarbon and therefore produces carbon dioxide when it burns. The beauty of looking at a fuel like hydrogen is that it doesn’t contain any carbon and, therefore, when it burns it produces no CO2.”

EasyJet expects the best way to lower emissions in the regional aviation sector to be a switch to hydrogen fuel and has invested “several million pounds” in the preliminary trials.

Chief Operating Officer for easyJet David Morgan said the company considered battery technology, but felt it wasn’t going to work for their larger commercial airplanes. Batteries weigh too much and hydrogen packs more punch per pound.

“[O]ur ambition is to take this technology to the air and indeed power a whole range of aircraft,” said Chief Technology Officer at Rolls-Royce Grazia Vittadini, as reported by Simple Flying.

What the tests have demonstrated so far is that a hydrogen-powered jet engine can be started and run at slow speeds, BBC News reported. Building an engine that can run on hydrogen and safely operate in a passenger airplane will require further research and investment.

“Combined with our work on Sustainable Aviation Fuel and further gas turbine efficiency, we are making real progress on the hard yards of research and development towards making Net Zero flight a reality,” said President of Civil Aerospace at Rolls-Royce Chris Cholerton, the Rolls-Royce website said.

Not only will new engines have to be built, but the airplanes that carry them will have to be redesigned. The temperature to turn hydrogen into a liquid is -423.4 degrees Fahrenheit, and it has to be turned back into gas before it can be burned. Hydrogen also requires around four times more space than kerosene, which is made by distilling crude oil.

The source of the hydrogen is also an issue. For the tests, “green hydrogen” was produced by using an electric current from wind and wave power to split water into oxygen and hydrogen, meaning the fuel was clean. However, most hydrogen used in industrial projects is made by mixing pressurized natural gas and hot steam, which necessitates a great deal of energy and produces a large amount of carbon dioxide.

“A lot of people are saying ‘we can use hydrogen, we need hydrogen.’ You hear it for cars, for trucks, for ships, for planes, for home heating, for chemicals,” said UK Policy Director of campaign group Transport and Environment Matt Finch, as reported by BBC News. “At the moment the UK effectively produces zero green hydrogen. To fulfill all the needs everyone wants is absolutely impossible.”

Because of this, Finch believes that green hydrogen supplies will likely need to be conserved, and he said governments might not prioritize aviation. Thus, hydrogen-fueled airplanes will probably not operate on a regular basis for decades, likely beginning with shorter flights. For longer distance flights, synthetic fuels are projected to be the best choice.