The airline industry accounted for roughly 2.4% of global carbon dioxide emissions in 2018,
a figure that’s predicted to rise to closer to 5% by 2050.
While long-distance travel has become such an ingrained part of many lives,
for business and pleasure, it’s clear that the consequences of air
travel on the environment are substantial. A solution, naturally, is a valuable thing,
and in three different new aircraft plans, Airbus says they have one.
Late in 2020, the French company announced a new concept, the ZEROe, simultaneously revealing
three different new aircraft designs, all under the same branding. The company says the new,
Hydrogen-fuelled aircraft could be in service by 2035, and form part of their wider plan to
“decarbonise the aviation industry”. The three designs range from relatively recognisable planes
with adaptations to their power source, to an unfamiliar reimagining of commercial aircraft.
Shaped like a cross between a space shuttle and a paper aeroplane, one concept is ambitious and
unfamiliar compared to what we’d see on our runways today. It has what Airbus are
calling “a blended wing body configuration”; essentially a single solid triangular form,
not unlike a smoothed out, commercial version of the angular stealth fighter.
That design is certainly the most eye-catching, with its cabin wide and spacious,
rather than cylindrical. The unusual layout has already been ‘proven’ as a shape concept
through a 3-metre wingspan ‘MAVERIC’ remote control version, though minus the Hydrogen power.
The other two look a little closer to conventional modern passenger aircraft. The turboprop model
looks a lot like a modern jet, though making use of twin propellers on either wing for propulsion.
The turbofan is an even more familiar reimagining of a typical passenger aircraft,
with huge jet-style propulsion engines mounted under either wing. The turbofan has a capacity
of between 120 and 200 people, and a range of an impressive 2,000 nautical miles. The blended body
aircraft would be similarly equipped in terms of distance and capacity, while the turboprop
model is aimed at shorter flights of up to 1,000 nautical miles, carrying 100 or so passengers.
The two more conventional designs, the turbofan and the turboprop, are, essentially,
adaptations of existing layouts allowing aircraft to run on hydrogen,
involving tanks located near the rear of the aircraft which supply to the engines.
The fresh, modern-looking ‘blended wing’ design makes use of a concept Airbus is
currently working on with Delft University in the Netherlands, that is thought to be up to 20%
more efficient in cutting through the air, and offer more layout options than current aircraft.
The improvement in efficiency exists even before the change in fuel source.
The obvious question, though, is how do Airbus intend to make
these aircraft zero emission? The answer lies in the use of Hydrogen.
The Hydrogen fuel cell is actually quite well established, having been used as far back as the
60s to power space rockets such as the Apollo 11 mission. In practise, the cells work through the
quick release of energy stored in the Hydrogen molecules, which generates electrical power,
using an electrochemical process, essentially consuming just Hydrogen and Oxygen.
Hydrogen enters a fuel cell on the anode side, where a catalyst splits it into negatively charged
electrons and positively charged particles, while oxygen from the air around the plane enters the
other, cathode, side of the cell. The positively charged particles are attracted to the cathode,
and so pass through a porous membrane to the opposite side of the cell, where they combine
with the oxygen to produce water as a byproduct. The electrons, flowing in the opposite direction,
become an electric current, which provides power, in this case to the aircraft engine.
This kind of fuel system is good for the environment compared to conventional systems,
first of all because of its relatively safe byproducts,
but also because of how the Hydrogen is produced in the first place.
As we all know, fossil fuels are not environmentally friendly on either end:
they cost energy to remove from the ground,
and create damaging byproducts when they’re burnt. Hydrogen, however, can be produced from seawater,
using green energy strategies such as wind or wave energy to provide the power source for
the initial production process. This makes both ‘ends’ of the supply green compared
to the product they’re replacing. The energy production also has no carbon dioxide byproducts.
The cell also has a benefit over conventional batteries, in that it continues to supply energy
for as long as a supply of Hydrogen can be pumped into the cell at the anode side,
essentially meaning the limitation, like with conventional fuel,
is how much Hydrogen can be carried on board (or, potentially, refuelled in air!).
As Hydrogen is relatively light, this opens up plenty of possibilities, too,
though it’s current storage tanks are heavier than conventional jet fuel, so the area will
need work. While this type of fuel is currently expensive, Hydrogen’s price is expected to drop
as it becomes more commonly used in green energy technologies, incentivising its wider production.
That’s not to say Hydrogen fuels are an absolute ideal. Water is a byproduct of the reactions used
in this process to generate power, and while water is not a pollutant, at least as we’d understand
the term, it is a greenhouse gas. That means it could still have an impact on global warming.
Nitrogen Oxide, another minor byproduct, is also less than ideal, though the levels of
Nitrogen oxide emissions are substantially lower than from conventional fuel. There is also some
fear of how combustible Hydrogen is, though studies suggest it is safer than gasoline.
Airbus are certainly exceptionally enthusiastic about the idea.
"I strongly believe that the use of hydrogen, both in synthetic fuels and as a primary power source
for commercial aircraft, has the potential to significantly reduce aviation's climate impact,"
Guillaume Faury, Airbus' CEO, said. The French government seems to agree,
having earmarked 10% of their 17 billion dollar covid rescue package for the airline industry
explicitly to be used on Hydrogen-powered aircraft.
The company is not just talking about a few aircraft, either, but a redefining of
the industry, with their three new concepts - and any later additions - at the heart of it.
“we won’t be satisfied with simply putting a hydrogen-powered aircraft into the air:
we’re targeting wide-scale adoption, and that starts with putting in place hydrogen
infrastructure worldwide,” Glenn Llewellyn, Vice President of Zero-Emission Aircraft,
said. The plan is, essentially, for a total change in the way aircraft
function from the mid-2030s onwards, as these aircraft come into commercial use.
Along the way, Airbus have also emphasized
the compatibility between hydrogen and other battery-powered sources,
and may look to utilise both in some of their aircraft, as an effective compromise solution,
not unlike a more environmentally leaning version of the modern-day hybrid car.
For all Airbus’ efforts, though, there is still cynicism about the idea in the industry, in
particular from those pointing to the development of sustainable fuels for use in current
aircraft - something that is already in process, though on a small scale - as being a potentially
more comfortable and straightforward route to a greener aviation industry. Alternative fuels are
already capable of a 70% reduction in emissions. That said, 70% is nowhere near on a par with
the Hydrogen based system Airbus propose, and two likely channels, we’d argue, are better than one.
Should Airbus’ concept come to pass, it certainly beats the industry’s rather palty efforts to
green itself so far: let’s face it, planting a few trees to offset your carbon footprint,
as some airlines offer as part of a ticket cost, is better than nothing,
but hardly a sustainable solution. With a bit of luck, Airbus’ idea might offer
commercial flight without the guilt, or the consequences for our planet’s future.
Would zero emission options make a change to how often you fly?
Would you be prepared to pay extra to use them? Tell us in the comments...