The European hydrogen-powered plane that will attempt a non-stop flight around the world

From a workshop on the west coast of France, aviation pioneer Bertrand Piccard and his partners are busily making final preparations for a flight that could completely alter the course of aviation.

When Piccard led a much-anticipated flight around the world in a plane powered by the sun a decade ago, it brought attention to climate change but didn’t hold out much hope of transforming air travel.

Now, the 66-year-old Swiss adventurer behind Solar Impulse is aiming higher, in the hopes of achieving a more environmentally-friendly commercial flight than that of fossil fuel-powered planes today – this time using super-chilled liquid hydrogen.

Climate Impulse is a project that was launched in February to fly a two-seater plane around the world non-stop in nine days, powered by what’s commonly referred to as green hydrogen.

That’s hydrogen extracted from water molecules using renewable electricity through a process called electrolysis.

The Climate Impulse team, backed by Airbus and the science incubator Syensqo, which is affiliated with the Belgian pharmaceuticals company Solvay, outlined its first-year achievements to journalists at a recent gathering in Les Sables d’Olonne, a coastal town famous for hosting the Vendee Globe round-the-world sailing race.

When can we expect Climate Impulse to take to the skies?

The first test flights are scheduled for next year, but the long-distance trip around the world is planned for 2028. Made with lightweight materials, the plane relies on several unproven technologies and is far from a guaranteed success.

Piccard says a major aircraft manufacturer wouldn’t take on the risk of producing a prototype such as the Climate Impulse in case it fails.

“It’s my duty to be a trailblazer,” he said in an interview. “We have to demonstrate that it’s achievable, then it becomes a huge encouragement for others to carry on”.

Even if this project is a success, experts are saying that green hydrogen-powered flights on a large commercial scale won’t be possible for decades at best. This project has attracted tens of millions of euros in investment, and the team of dozens of employees is growing.

The solar-powered plane was a significant technological achievement in 2015, but it wasn’t suitable for large-scale use, according to Raphael Dinelli, an engineer and co-pilot with Climate Impulse. The plane’s limited range meant it had to make over a dozen stops on its trip around the world.

Climate Impulse is intended to lift off on its own, travel approximately 40,000 km (about 25,000 miles) around the Earth along the Equator and return to its starting point without any mid-air refueling – and without making any stops along the way.

How does Climate Impulse operate?

The controlled release of liquid hydrogen from super-insulated tanks under the plane’s wings generates energy that seeps into the membrane of a fuel cell which powers the aircraft.

“The plane has a wingspan of the same size as an Airbus 320: 34 metres or about 110 feet. It weighs 5 and a half tons and flies at 180 kilometres per hour – which is equivalent to 100 knots at an altitude of 10,000 feet or 3,000 metres,” Piccard said on Thursday.

One of the goals is to harness energy from the “turbulence section” of the air, which airlines may be able to use in the future to reduce fuel consumption, he said.

Because it’s hydrogen, the only emissions will be water vapour. Still, outside experts warn that the environmental impact of such water-vapour “contrails” remains unknown in a real-world or large-scale situation.

The International Energy Agency states that air travel is accountable for roughly two percent of the world’s total carbon dioxide emissions.

Hydrogen has been used in flights for years, but only as a gas, not as a liquid. Scaling up the use of liquid hydrogen will take time. At present, fossil fuels, which are less expensive and more efficient, are still the main source of hydrogen used today.

Many governments wish to produce more green hydrogen, but for the moment, the world cannot generate sufficient clean electricity to meet land-based power demands, not to mention sufficient quantities for large-scale aviation use.

What happens next?

Over the past year, the team has created the cockpit casing, begun constructing the wing spar, and completed the interior components. These consist of swivel seats, a bed and a stationary exercise bike, designed to improve blood flow for the co-pilots who will be confined to a small cockpit for nine days in low-oxygen conditions.

The hardest parts await.

Tests are scheduled for this year on the fuel cells and propulsion systems to determine if the electric motor, propeller and batteries could be operational for an initial all-electric flight phase.

The most challenging part is to manage the flow of liquid hydrogen in a way that ensures the most efficient use of it for the longest possible distance, Dinelli said.

Another challenge: the liquid hydrogen must be kept at a temperature of -253 degrees Celsius, which is almost absolute zero. Ensuring that the tank doesn’t leak is of utmost importance.

Liquid hydrogen is highly combustible, so any leakage could have dreadful consequences.

Is there a future for flights powered by hydrogen produced from green sources?

Liquid hydrogen has been primarily associated with its use as a propellant to propel rockets into space up to this point.

Aviation’s share of carbon emissions is relatively small at present, but it’s increasing at a rate faster than in any other industry because the development of electric-powered planes is lagging far behind progress made with electric cars and trucks on the ground.

Electric vehicle batteries are currently quite heavy on the roads, and reducing their weight will be vital for making electric-powered flight a reality.

“We haven’t had an equivalent of the ‘Tesla moment’ in aviation yet,” said Nikhil Sachdeva, an expert in how the aviation sector can transition to more environmentally friendly technologies at consulting firm Roland Berger.

“H2 has the potential to be the game-changer for aviation, which is why it’s worth getting it spot on”.

We’re finding it “extraordinarily difficult” to handle super-cold liquid hydrogen, and we can only manage it for a few minutes at the moment. And what we’re talking about here is doing it safely for hours.

But Solar Impulse faced pessimism too, he said, and Piccard’s team has “proven it can do what people would consider impossible”.