Rolls-Royce Achieves Controlled Hydrogen Burn


Rolls-Royce says it has run a modified version of a standard jet engine at takeoff power using hydrogen for fuel. The company said it’s a key accomplishment in developing future carbon-free designs that can power future aircraft. “This involved overcoming significant engineering challenges as hydrogen burns far hotter and more rapidly than kerosene,” Rolls-Royce said. The tests were carried out on a modified Pearl 700 engine.

Newly developed fuel spray nozzles mix air with the hydrogen at precise levels to control the burn rate. A full ground test of the new technology is next. The work is being carried out by a consortium of companies and academics led by easyJet and Roll-Royce called the UK Hydrogen in Aviation alliance. “This is an incredible achievement in a short space of time,” said Grazia Vittadini, technology chief for Rolls-Royce. “Controlling the combustion process is one of the key technology challenges the industry faces in making hydrogen a real aviation fuel of the future. We have achieved that, and it makes us eager to keep moving forward.”

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. Their real problem is producing hydrogen without stripping it from hydrocarbons, leaving behind lots of … carbon.

    • Hydrogen has been tried now for a few hundred years. It’s not viable as a general use engine fuel. Only way it would be adopted is if common sense is displaced with “hopes and dreams”. Sorry, but I lived through all this back in the 70’s too and it did not work then either.

  2. Hydrogen can be extracted from water; no hydrocarbons required. There is a lot of research going on to find catalysts that improve the efficiency of the electrolysis process to make cheaper hydrogen fuel.

    The bane of hydrogen as a fuel is that it’s hard to store. That’s where a breakthrough is needed. Right now it has to be stored in tanks at extremely high pressures in order to carry enough to be useful. Hydrogen is light but the tanks are not.

    Thermodynamically, the fact that hydrogen burns hotter is a good thing, although engines designed for Jet-A might have a problem taking advantage of the higher temperatures.

    • Hydrogen extracted from water will still uses hydrocarbons for the vast amounts of electricity required. There is no “extra” solar on the grid or “new” hydro for this so the process will require added oil/gas/coal plants to create the new supply of electricity to separate and liquefy Hydrogen. Ironically this is not sustainable since it requires more energy in that you get from the finished product that is supplied.

      This is old known technology and has been tried (and failed) since about 1806.
      Funny how it still comes up even after a few centuries of trials showing that it’s not viable as an engine fuel.

  3. Nice to see the new technical frontiers achieved.

    Work is needed to recover hydrogen takes tremendous amounts of electricity to split the hydrogen from water, which is currently uneconomical. The other method Steam–methane reforming is cost effective, but has a byproduct of CO2.

    More work needed to commercialize the hydrogen Jet and obtaining the hydrogen, good to see progress developing.

    • Using Hydrogen is a terrible idea.
      The energy you get out is less than you put in.
      That is NOT a solution for anything unless the plan is to waste energy.

  4. I don’t think carbon production counts if it’s a by-product of creating clean burning fuel. Only the burning of the fuel matters. This is why ethanol is still found in regular gas at the pump.

    Steam-methane reforming it is!

      • Hydrogen can only be compressed until it liquifies, at which point it has about one third of the energy density with respect to volume as jet fuel does – and the tanks can’t be shoehorned into oddball spaces the way conventional tanks can.

        The weight penalty imposed by high pressure containment vessels is somewhat offset by the fact that hydrogen has about triple the energy density with respect to weight as jet fuel does.

      • The problem can be understood when your plane is parked on the ramp in the summer. Imagine topping off your plane with Hydrogen and when you take off an hour later that 1/3 of it has “vented” away.

  5. Unfortunately, you cannot liquefy hydrogen by simply compressing it. At ambient conditions, it is above its critical point, so it can only be liquefied through both compression and refrigeration. Trying to operate a jet engine using compressed hydrogen is simply not practical due to the size, weight and limited storage capacity of the high-pressure tanks. Even at the extreme pressure needed for the containment vessels their overall storage capacity is nowhere near that of a simple jet fuel tank. Storing hydrogen as a liquid is the only practical way to carry a sufficient volume of fuel for commercial aircraft. That carries its own set of problems due to LH2’s storage temperature of -423 degrees F, just 40 degrees above absolute zero (-460). While the storage and handling of LH2 is well established in the rocket industry, it would require a completely new set of facilities and operating procedures at an airport. Don’t get me wrong, I fully support R&D into alternative fuels and engines, but I have to remain realistic about what it will take to make any of this work. When Elon Musk began developing his Raptor engines for the Falcon rockets, he avoided hydrogen and used liquid methane as the fuel instead. While still a cryogenic liquid, at -260 degrees it is much easier to handle and store than hydrogen. Even though it is a fossil fuel, its carbon to hydrogen ratio (1-4) is the lowest of any hydrocarbon – far lower than the kerosene used in most other liquid-fueled rockets or the jet A used in commercial aircraft.