Rolls-Royce just successfully tested the world’s first jet engine powered by green hydrogen. Cleaner and producing zero carbon emissions, the aviation milestone signals a huge step forward for sustainable air travel. But there’s still more than one catch that’s stopping this method from getting off the ground.

During last year’s COP26 (the annual United Nations climate summit), Rolls-Royce announced it was joining the UN’s Race to Zero initiative, a global campaign designed to foster immediate action to reduce emissions before climate change reaches a catastrophic tipping point. The company pledged to achieve carbon neutral operations by 2050, committing to utilise its technological capabilities to transform the industries it participates in, such as aviation, logistics and transport, enabling multiple economic sectors to likewise achieve net zero carbon within the same timeline.

The significance of this achievement cannot be understated, it paves the way for greener methods of air travel.

This week, Rolls-Royce took a major step toward realising their environmental ambitions. As part of a joint project with easyJet and the European Marine Energy Centre (EMEC), the British aerospace giant successfully tested the world’s first hydrogen powered jet engine. The converted AE 2100-A regional aircraft jet engine was fuelled with green hydrogen, supplied by EMEC, in turn generated by renewable energy at the centre’s hydrogen production facillity.

The significance of this achievement cannot be understated, it paves the way for greener methods of air travel. As a fuel source, hydrogen is far more environmentally friendly, producing only trace amounts of CO2. Instead, the main emissions of this hydrogen technology are water vapor and warm air. That matters when you consider that the aviation industry is routinely one of the leading contributors to air pollution, meaning this breakthrough may herald the actualisation of carbon neutrality for one of the biggest emissions emitters.

Looking Forward

This is a historic moment for aviation, traditionally one of the most difficult industries to clean up, due to its complexity as compared to other modes of transport. After all, electric airplanes just don’t scale, mainly because the battery to weight ratio is a never-ending game. One a related note, it remains to be seen then how this new development would translate to larger format planes, as the engine tested was what is commonly found in turboprop aircraft, designed for slower speed, short-haul flights.

Whilst the successful test is cause for celebration, there is however one catch to be considered, that being the source of fuel and how it is generated. Compared to standard sources of the hydrogen, EMEC provided a ‘green’ variety, named due to its renewable origins of wind and tidal energy. Unfortunately, most hydrogen today is still made using gas, as it is a far less expensive, yet equally less environmentally friendly, than what EMEC produced.

Then there is the fact that jet fuel has a greater density as compared to hydrogen, meaning you need less of it to power the same flight. That impacts many aspects, including the size of the aircraft, distance it can travel, time to refuel and cost of the fuel itself.

This recent test did help to advance the cause of zero emission air travel, but there are still several factors that need to be addressed before planes powered by green hydrogen become a reality. Still, there is hope that this proof of concept can take flight sooner than later. ■