Airbus SAS 2022
A rendering of the Airbus ZEROe: Fuel Cell Engine Demonstrator, a concept for a converted Airbus A380 featuring hydrogen fuel cell engines (pictured above and behind the wings). Airbus says it's planning test flights for around 2026, part of its long-term ambition to launch a zero-emission commercial aircraft by 2035.
Hervé Gousse/Airbus SAS
A model of the Airbus ZEROe Fuel Cell Engine, unveiled on November 30. Hydrogen fuel cells emit only water and warm air.
Courtesy Rolls-Royce plc
On November 28, Rolls-Royce announced it had successfully tested its AE2100 engine using liquid hydrogen fuel as part of a partnership with airline easyJet. The engine is currently used in commercial and military airplanes.
Etihad
As aviation attempts to decarbonize, a new generation of aircraft that does away with fossil fuels is emerging. Etihad's Greenliner program has tested new ways to reduce carbon emissions since 2019. By applying them to a single London to Abu Dhabi service in October 2021, the airline says it was able to reduce overall emissions by 72%.
Skydweller Aero Inc.
Solar-powered Skydweller, which is based off Solar Impulse 2, an aircraft that has set numerous flight records.
Skydweller Aero Inc.
Skydweller Aero aims to produce the world's first commercially viable "pseudo-satellite" -- a solar-powered airplane capable of staying in the sky for months at a time. Skydweller is pictured landing after its first flight, in December 2020. The men on bikes are there to stabilize the aircraft by catching the poles protruding from the wing, a necessary step because of its tremendous wingspan.
Jean Revillard/Solar Impulse 2/Getty Images
In 2016, Solar Impulse 2 circumnavigated the Earth without using a drop of fuel. It's pictured here on July 26, 2016, before landing in Abu Dhabi to complete its 26,000-mile (42,000-kilometer) journey.
Courtesy Airbus
Airbus plans for three hydrogen-powered, zero-emission aircraft which can carry 100 to 200 passengers. It hopes to launch the first ZEROe aircraft in 2035.
ZeroAvia
On September 24 2020, ZeroAvia flew the world's largest hydrogen-powered aircraft at Cranfield Airport in England, showing the possibilities of hydrogen fuel for aviation.
Eviation Aircraft
While some are exploring hydrogen power, others are testing electric planes. Washington State-based Eviation Aircraft is behind the nine-passenger all-electric Alice aircraft, which produces no carbon emissions.
Eviation Aircraft
The aircraft, shown here as a rendering, has a range of 440 miles and is intended for feeder routes. It also comes in a cargo version; DHL Express has ordered 12 slated for service in 2024..
Courtesy Crystal Cabin Award
Alice's innovative interior won the "Cabin Concepts" category at the Crystal Cabin Award 2020.
Don MacKinnon/AFP/Getty Images
In December 2019, Vancouver-based seaplane company Harbour Air made history with the first all-electric commercial aircraft flight. The de Havilland DHC-2 Beaver seaplane, which was first flown in 1947, was retrofitted with a 750 horsepower magni500 electric engine from magniX.
magniX
MagniX made headlines again in June 2020 when AeroTEC's nine-seater eCaravan -- powered by the magni500 electric propulsion system -- became the largest all-electric commercial aircraft to fly.
Airbus
On March 25 2022, an Airbus A380, the world's largest commercial passenger airliner, completed a test flight powered entirely by SAF -- sustainable aviation fuel -- composed mainly of cooking oil.
Faradair Aerospace
While energy sources are still evolving, UK-based Faradair Aerospace is developing a design to squeeze the maximum efficiency out of whichever fuel prevails.
Faradair Aerospace
Faradair's 18-passenger BEHA aircraft, made from lightweight composite and shown here in a rendering, can carry a five-ton payload and has a 1,150-mile range.
CNN  — 

Airbus has announced it is developing a hydrogen-powered fuel cell engine – and that it plans to test it on the largest commercial airplane ever to take to the skies.

The French aviation giant revealed at Airbus Summit 2022 on November 30 that it will mount the engine between the wings and the tail of a modified A380 superjumbo. Test flights are estimated for 2026, as part of the Airbus ZEROe initiative to launch a zero-emission aircraft by 2035.

“In terms of aerodynamics, the A380 is a very stable aircraft. So the pod attached to the rear fuselage via the stub doesn’t pose much of an issue,” said Mathias Andriamisaina, head of ZEROe demonstrators and tests at Airbus, in a statement.

Airbus had previously revealed concept designs for an aircraft utilizing liquid hydrogen fuel and combustion engines, but vice president of Zero-Emission Aircraft Glenn Llewellyn suggested fuel cells alone might be sufficient to power smaller commercial aircraft.

The engine uses fuel cells to convert the hydrogen into electricity, which then powers a propeller. “At scale, and if the technology targets were achieved, fuel cell engines may be able to power a 100-passenger aircraft with a range of approximately 1,000 nautical miles,” he said.

Hervé Gousse/Airbus SAS
A model of Airbus' ZEROe Fuel Cell Engine, unveiled at the Airbus Summit 2022 on November 30.

The journey to decarbonize air travel

Hydrogen has long been touted as a sustainable alternative to traditional jet fuel, either as a combustible fuel or used to generate electricity via fuel cells. The aviation industry produces 2.8% of global CO2 emissions but it faces harder challenges than other sectors in decarbonizing itself, and progress has been slow.

While hydrogen-powered aircraft have been in development since the mid-20th Century, they have faced significant obstacles, mainly hydrogen’s low energy density compared to kerosene, and the latter’s availability and historically low price.

The infrastructure required to produce and distribute hydrogen is also an issue. At Airbus Summit, Airbus boss Guillaume Faury warned that this was “a big concern” and it could derail the company’s plans to introduce a hydrogen-powered aircraft by 2035.

Airbus
Airbus has previously announced a variety of hydrogen-powered airplane concepts as part of its ZEROe program, including the Blended Wing Body.

But hydrogen could become a key asset in commercial aviation even before entirely new aircraft based around it are developed. Days before Airbus’ announcement, Rolls-Royce and budget airline EasyJet said they had successfully converted a regular airplane engine to run on liquid hydrogen fuel — a world first, they claim.

The ground test involved a type of Rolls-Royce engine currently used in commercial and military airplanes, and a second test is already planned. Next, the trial will expand to a Rolls-Royce Pearl 15 engine, which is used to power Bombardier business jets capable of long-haul flight.

Courtesy Rolls-Royce plc
Rolls-Royce AE2100 Hydrogen Demonstrator engine preparing for test at RAF Boscombe Down

Future fuel

The fuel for Rolls-Royce’s test was sourced from wind and tidal energy, an example of “green” hydrogen.

Green hydrogen is commonly derived via the electrolysis of water – using electricity to separate water into hydrogen and oxygen – and using renewably sourced electricity to do so. “Gray” hydrogen uses non-renewable electricity, while “blue” hydrogen is similar to gray, but captures most of the carbon emitted in production. Green hydrogen is considered the cleanest option.

View this interactive content on CNN.com

How the hydrogen is utilized also creates a different footprint. Burning liquid hydrogen in the open-air releases a small amount of greenhouse gas nitrous oxide. Using green hydrogen to generate electricity in a fuel cell, however, emits only water and warm air.

The next decade will reveal which of the hydrogen technologies will take off. Either would be a positive step in securing the long-term viability of low-carbon air travel.