Although it is a vital component of the global economy, aviation is a
significant contributor to harmful greenhouse gas emissions. A move in the
right direction could be provided by the first-ever hydrogen jet
motor.
Contrary to land transportation, aircraft has strict weight restrictions,
making it difficult to decarbonize using batteries. Even with great
advancement, the energy density of today's most sophisticated lithium-ion
cells is still significantly lower than that of traditional aircraft fuel.
Energy density is a measure of how much electricity can be packed into a
pound.
This presents a challenge for airplanes because it means that having more
batteries won't produce enough additional power to make up for the
additional weight of the batteries. Even at its potential maximal capacity,
lithium-ion technology won't deliver high enough energy densities for even
medium-haul flights, and novel battery chemistries are still a long way
off.
Because of this, interest in hydrogen as a possible aviation fuel is
increasing. Although it still lacks kerosene's energy density, it has a lot
more power than batteries and emits no pollutants when consumed.
Though it's not a direct replacement for jet fuel, using hydrogen to power
aircraft will necessitate major redesigns. However, the first ground
demonstration of a jet engine powered by hydrogen was conducted by business
airline easyJet and jet engine manufacturer Rolls-Royce.
The accomplishment of this hydrogen test,
according
to Grazia Vittadini, chief technology officer at Rolls-Royce, "is an
exciting milestone." We are pressing the envelope to learn more about
hydrogen's zero-carbon potential, which could help reshape the future of
flying.
The demonstration was carried out using a modified Rolls-Royce AE 2100
engine and hydrogen generated by the European Marine Energy Centre on the
Scottish Orkney Islands using sustainable tidal energy.
It's crucial to note that
not all hydrogen is made identical. The fuel produced by converting water into hydrogen and oxygen while
using sustainable energy is referred to as "green hydrogen." The most
popular type of hydrogen today, however, is gray hydrogen, which is made
from fossil fuels and produces a significant amount of greenhouse gas
pollution.
The businesses praised the development as a crucial move in the aviation
industry's decarbonization. But before hydrogen is likely to be used to
power a sizable number of airplanes, a long distance still needs to be
traveled. To begin with, starting an engine on a test device that is located
on the ground is very different from using it to propel an aircraft.
Although hydrogen has a higher energy density than batteries, the
BBC
reports that an airplane would require almost four times as much liquid
hydrogen as jet gasoline to travel the same distance.
Additionally, liquid hydrogen must be maintained under pressure and cooled
to -253C. The fuel containers and systems required to transport the hydrogen
to the turbines would need to be significantly bigger and more complex,
necessitating a full rethink of the aircraft. However, despite these
difficulties, easyJet is certain that hydrogen is the most practical choice
for decarbonizing aircraft.
As easyJet's chief operating officer told the BBC, "We started looking at
what might power the aircraft of the future a few years ago." "We looked at
battery technology, and it was pretty obvious that it probably wouldn't work
for the big business planes we operate. We've determined that hydrogen is a
very thrilling idea for us.
Not only them, either. Airbus has been working on several hydrogen-fueled
aircraft concepts, and
last week it revealed intentions to test a plane's hydrogen fuel cell motor. Fuel
cells use chemical processes to transform hydrogen into energy, which can
then power an electric engine, as opposed to burning the hydrogen. By 2026,
the firm hopes to conduct the first A380 aircraft test flights.
Given the meager quantity of green hydrogen presently generated, it is
uncertain whether there will ever be enough fuel to sustain flight, even if
these prototypes succeed in leaving the lab. Nevertheless, hydrogen might be
a key component of a more environmentally friendly aircraft future, so any
advancements are to be commended.
Image Credit: Rolls-Royce
