Transcriber: Khoa Vo Reviewer: David DeRuwe
So today I’m going to talk about ammonia.
It’s a rather smelly but invisible gas that consists of a nitrogen atom
bonded to three hydrogen atoms in a pyramidal structure.
This gas underpins a large amount
of the things we take for granted in modern life,
from farming to fashion.
But our relationship with it began thousands of years in the past
with a civilization that was more concerned
with great pyramids than microscopic ones -
the ancient Egyptians.
In the Siwa oasis in modern-day Libya,
Pliny the Elder tells of the temple of Zeus Ammon
where the priests there used ammonium chloride,
a salt containing ammonia and chlorine
for their medicinal and religious practices on the site.
And in Rome, the togas that we associate as being so white and clean
used [ammonia derived from urine] to clean and bleach those garments.
This became such a widespread practice in the city
that in 79 CE, Emperor Vespasian declared “Urinae Vectigal,”
or a urine tax to deal with this issue and turn the smelly collection of urine
in the city into a monetary gain for the empire.
By the 10th century CE,
ammonium chloride was being traded from the Far East to Europe
along the Silk Road, along with the commodities
like spices and silk we associate with that path today.
These natural sources of ammonia were very useful to our ancestors,
but it's not how we produce ammonia in modern life.
That process began in 1904 with Fritz Haber developing
a chemical synthesis to make ammonia from nitrogen from the air and hydrogen,
along with a fellow German compatriot, Carl Bosch.
In 1914, they commissioned the first Haber-Bosch processing plant
to produce ammonia for the war effort for Germany in World War One.
This was necessary because the British had blockaded the ports
that the German empire used to import guano,
a natural source of ammonia from South America.
And while this was quite a controversial start for synthetic ammonia production,
it revolutionized farming and textiles in the 20th century.
This was because of the excess nitrogen available from the synthetic ammonia.
It was used to create the fertilizers that we use in modern farming,
which increase the yields of crops around the world.
This resulted in millions of people being lifted out of food poverty and insecurity.
And further to this,
the availability of this cheap ammonia
resulted in the creation of synthetic fibers such as nylon
that we’re all familiar with today.
By the 1930s, ammonia had become such a useful chemical to us as a species
that we were using it in refrigeration practices,
and what this meant was we were able to increase the shelf life
of foods and medicines around the world,
which meant that they were more able to get to the people that need them.
This is where my personal journey with ammonia began,
researching sustainable and alternative refrigeration methods at Queen’s.
Ammonia has been used for a long time, and we are coming back
to considering using it as an alternative to the modern HFCs and CFCs
we use in our air conditioners and freezers today.
But ammonia is used for much more than that.
We use it to make our food; we use it to make our clothes as well.
And this has created a network
that produces 176 million tons of ammonia every year.
That number is a little bit obscure, so to put that into perspective,
the only things we make more of every year on the planet are cement and steel.
Along with the other large chemicals that we produce,
there’s an associated environmental impact from this process:
The energy and the electricity we use
and the feedstock that we get our hydrogen from
all derive from fossil fuels, mostly coal and natural gas,
and these have an associated carbon emission
that equates to 300 million extra tons of CO2 entering our atmosphere every year.
That’s about equivalent to the entire global shipping sector
that moves all the goods we use as a species around the planet every year,
not a huge amount,
But ammonia presents a unique opportunity
in this group of massive chemicals that we produce,
in that it contains no carbon - it only contains nitrogen and hydrogen.
So the carbon that we use is further up in the process,
and if we can remove that by decarbonising the electricity production;
by using solar, wind, geothermal or tidal energy to supply it;
and we create the hydrogen we use to make it
using technology such as fuel cells to split water into hydrogen and oxygen,
we can secure and make a more sustainable future
for food production and textile production in modern life.
This opportunity is something that we need to grasp,
as ammonia is one of the only chemicals we produce at this scale
that doesn’t contain carbon,
and what it will do is it will allow us to enter
the next revolution that this very smelly friend of ours can present to us:
the energy revolution.
One of the main problems we are having right now
with transitioning from carbon-based energy production to hydrogen-based
is hydrogen is very volatile and very dangerous when stored or handled.
It also has the issue that we don’t have the infrastructure or the network we need
to produce it up in the amounts that we need to create the energy
that we all use every day.
But ammonia presents an opportunity to sidestep those issues.
We already transport it in vast quantities around the world,
and over the last century, we’ve developed a network
of production and handling that’s only rivaled by natural gas.
If we use ammonia and its three hydrogen atoms
as a hydrogen vector to transport hydrogen around the planet,
we can overcome these hurdles
and more quickly decarbonise our energy production as a species.
So despite being a very old and very smelly friend,
ammonia is constantly updating its relationship status with us
to a more sustainable future that we can all enjoy.
Thank you.