(upbeat funky music)
- When this plane flies,
the only emission that comes out of its tailpipe
is the same thing that's in this glass, water.
It's because this plane is powered by a hydrogen fuel cell.
Now I'll go into how this works in a second,
but what's important is that some in the aviation industry
believe that this technology,
hydrogen as a fuel,
could hold the key to decarbonizing flight.
- What we need to do is eliminate
the climate impact of flying.
Hydrogen looks like it can allow us to do that.
- But the physics and economics around hydrogen
mean that the odds of your future flight
being hydrogen-powered is very dependent
on how far you plan on flying.
So is hydrogen flight here,
is it in the future, or is it already too late?
Before we get into how planes like this work,
it's important to consider why the aviation industry
is thinking about hydrogen at all.
In 2021, aviation was responsible
for over 2% of global energy-related CO2 emissions.
With flights pumping out a little over 720 megatons
of CO2 into the atmosphere,
and before the pandemic
that was even higher, at over 1,000 megatons.
Even though engines are getting more fuel efficient
as global travel continues to recover,
aviation emissions are growing.
So in order to hit targets laid out
in the Paris Climate Accords,
various aviation groups such as IATA,
the International Air Transport Association,
have set the industry an ambitious target,
net zero emissions by 2050.
While alternative fuels
like sustainable aviation fuel, or SAF,
could provide a pathway to net zero,
as the fuel still emits CO2,
hydrogen could provide a route to absolutely zero emissions.
So how's it work?
One method is to use hydrogen combustion
where the hydrogen replaces jet fuel
and is ignited to drive the propellers.
Now, hydrogen is highly flammable.
So while that means you get a lot of bang for your buck,
almost three times that of jet fuel by weight,
it also means that its use in aviation history
has been somewhat checkered.
(Hindenburg exploding)
So the other less fiery way
to use hydrogen in planes like this
is with a hydrogen fuel cell.
Much like a battery,
hydrogen fuel cells work
by creating a flow of electrons around a circuit.
Hydrogen is fed into one side of a cell, the anode,
and oxygen into the other, the cathode,
with a membrane sat between the two.
At the anode, the hydrogen flows over a catalyst,
which separates the protons and electrons.
Now, the hydrogen protons
are able to pass through the membrane to reach the oxygen,
but the electrons can't.
Instead, they have to make their way around a circuit
and by doing so, power a motor
until they can reunite with the hydrogen protons
and the oxygen to form H2O or water,
which along with heat
is the only emission that comes from this whole process.
And it's that exact principle
that's happening in this plane behind me.
This is ZeroAvia's test plane,
a 19-seat aircraft,
which had its debut hydrogen-powered flight
earlier this year.
I caught up with ZeroAvia's CEO at the Paris Air Show.
- Today, we have four out of the top 10 airlines
as our customers, - Oh. right.
- already people reserve production slots
because they want to be the first.
- Right now, it's only this left-hand engine
that's hydrogen-powered,
but once the company completes testing
it has plans to develop engines
to be able to carry 19 passengers
around 300 nautical miles by 2025.
Two other small startups pursuing hydrogen flight,
are US-based Universal Hydrogen
who were flown a similar plane to ZeroAvia,
and German-based H2FLY.
- We started in 2006
to develop this kind of technology.
At the moment,
we are in the seventh generation of powertrains,
and I think the technology is today here,
- [Narrator] But it's not just small startups
or small aircraft,
one major plane manufacturer
has thrown its weight behind hydrogen in a big way, Airbus.
- We're hoping to introduce
a hydrogen-powered aircraft in 2035,
with zero CO2,
so we're not just talking about net zero,
we're talking about absolute zero.
- Airbus has plans
for three different commercial hydrogen planes,
a turbofan, a propeller-powered plane,
and a longer range further into the future,
blended wing design.
- Our view is that 2035 is not soon enough,
and we've got an urgency
to be bringing these technologies to the market.
- But while Airbus may be backing hydrogen,
Boeing on the other hand,
appears less certain about its role in powering aircraft.
- We've learned a lot with hydrogen,
and we've flown
six different forms of airplanes on hydrogen.
So we just think that its impact on airplanes, airports,
and pipelines is greater,
and therefore, it won't help us as soon
as some of these other solutions
that are less impactful. - [Narrator] Yeah.
- [Chris] And if the goal is 2050,
we've gotta work on the things that'll help us the fastest.
- So why is that?
Well, while hydrogen
might be one of the most abundant elements in the Universe,
on Earth, it's almost always attached
to something else, like oxygen to form water.
To isolate it requires using an electrolyzer,
which is the reverse of a fuel cell,
and that requires energy.
Now, in order for hydrogen fuel
to be considered carbon neutral,
known as green hydrogen,
the energy source that you use in that electrolyzer,
also has to be renewable, like solar.
And right now, green hydrogen is expensive
and kind of hard to come by.
- The different decarbonized energies
that we're looking at
are more expensive than kerosene is today.
So there's going to be an increase in price,
in cost of the airlines,
and that's likely to have an impact on ticket prices.
- Then there's the infrastructure around delivering it.
While hydrogen electrolyzers can be set up
pretty much anywhere,
the amount needed to power aviation around the globe
would require investment,
potentially more than other sustainable fuels
that can be piped into airports
using the same infrastructure as jet fuel.
- We expect that in Europe,
we will have 10 to 12 billion of Euros investment
just to replace the carnosine infrastructure with hydrogen.
- And then there's the plane itself.
While hydrogen may be lighter than jet fuel,
it's actually less energy-dense
and takes more space than the equivalent amount of jet fuel.
That's why the windows on Airbus rendered
on their hydrogen aircraft stop here
because all of this would be used as a fuel tank.
Obviously, less seats means less passengers,
which potentially means less revenue.
What's more, even with all that space,
right now it's still only enough hydrogen
to do short flights,
meaning that trans-oceanic routes
aren't currently possible on hydrogen,
unless it's a small ocean.
- To really unleash the power of hydrogen,
to really have a huge benefit
even to go long range with hydrogen,
we have to rethink the way we fly.
We have to rethink the shape of the planes
- And therein lies the problem.
When it comes to larger planes,
it could already be too late for hydrogen to take off.
The planes that are on sale today
by the likes of Boeing and Airbus
have a backlog of roughly six years depending on the plane.
Those planes are then in service
for an average of around 20 years.
And that means that the planes that are being sold today
are the planes that we'll be using in 2050,
and looking around,
none of them are hydrogen compatible.
- So hydrogen in its raw form isn't compatible
with those existing aircraft.
And that's why sustainable aviation fuel
is really important.
- There's also a chance that it could stay that way.
See, that target set by IATA and others
was for net zero by 2050, not absolute zero.
And if airlines achieve their net zero aims using SAF,
there's questions around
whether they would then choose to invest millions
into renewing their entire fleet to be hydrogen planes,
and they've technically,
already hit their environmental targets.
All this means that while you may see
a greater number of hydrogen planes
in the skies over the next few years
unless you're taking a relatively short trip,
you could be waiting a long time
before you step foot aboard a hydrogen plane.
(upbeat music)