Either you believe man-made climate change is a nightmarish existential threat to civilization, or
you lack basic critical thinking skills and you’re about to write something dim in the comments.
Whichever it is, let’s at least agree mankind is dumping too much carbon into the atmosphere.
Not convinced? Here’s some numbers. Prior to the industrial revolution,
earth’s atmospheric carbon dioxide concentration was chilling somewhere around 280 parts
per million. If we want to keep our planet habitable, respectable climatologists all agree,
we need to keep that number below 350 parts per million, tops.
Anyway, since you ask, as of this year we’re roaring past 420.
Nice. Except, not.
Of course we all know emitting less carbon dioxide would help avoid a
catastrophic runaway greenhouse effect that will in turn destabilise ecosystems,
interrupt food supplies and prompt a historic global refugee crisis.
But what if there was a way of extracting the carbon that’s already up there,
in effect setting back the clock?
Join us today as we anxiously gaze at the skies and ask: can carbon capture save the planet?
Carbon capture is a very new field, and it’s evolving rapidly.
But for our purposes, let’s say that there are essentially two types of carbon capture,
and two types of carbon disposal.
Carbon dioxide, CO2, can be removed from industrial emissions at source – say,
the belching chimney of a coal-fired power station – before it’s released into the
atmosphere. This so-called ‘flue gas’ approach is already in use at certain select facilities,
like the Boundary Dam coal-fired plant near the town of Estevan in Saskatchewan, Canada.
This specific process, which employs sophisticated ammonia-based chemistry,
successfully captures around a million metric tonnes of C02 every year, or 90% of the
Saskatchewan plant’s emissions. The downside is the equipment to make that happen cost $1.3bn.
The other kind of carbon capture is far more exciting, and is named DAC,
or Direct Air Capture. DAC employs giant banks of fans, pretty much,
which suck already-emitted carbon out of the ambient atmosphere. This technology
is very promising, but has yet to be deployed at any useful scale.
More on those shortly, after we touch on the vexed question of what actually needs to be done with
that carbon once it’s captured, either through flue gas extraction or snatched out of thin air.
Again, there are two broad approaches here. CCS stands for Carbon Capture and Storage.
Under CCS the recovered C02 is stashed out of harm’s way,
typically underground in secure rock formations. CCU, on the other hand, stands for Carbon Capture
and Utilisation. With CCU the carbon is actually recycled and put to good use, for instance as a
raw material or feedstock.. This sounds great, but raises plenty of questions of its own.
Let’s look at a couple of CCS – Carbon Capture and Storage – initiatives happening right now.
Northern Lights is a hyper-ambitious project being carried out in a collaboration between oil
giants Shell, Total, Equinor and the Norwegian government. The idea is that emissions will
be extracted from industrial flue-gases from factories across Norway – eventually all across
Europe – and carried over pipelines to a coastal terminal at Øygarden on the North Sea coast.
From there, specially designed ships will ferry the noxious CO2 waste out to sea,
where it will be injected into storage reservoirs 2,600 metres beneath the sea bed.
The first project of its kind to be attempted at scale,
Northern Lights promises it can initially store up 1.5 million tonnes of C02 a year,
which should increase to five million tonnes a year as the model – CCS as a service,
in effect – proves its efficacy. We’ll see, anyway, when it’s up and running in 2024.
If you can’t wait that long, another very exciting Carbon Capture and Storage scheme, named Orca,
comes on stream this September in Iceland. Conceived by Swiss startup Climeworks,
Orca catches its carbon via futuristic Direct Air Capture, essentially running gigantic banks
of fans which suck C02 into clever filters, which are then heated to separate the pollutant
before pumping it into safe basaltic rocks far below the rugged Icelandic landscape.
The question of where we shove all that CO2 is of course central to the problem of
carbon capture. Basalt rocks are ideal, not only because they’re very common,
but because CO2 reacts with basalts’ naturally abundant magnesium and calcium,
transforming the unhelpful element into solid minerals like dolomite, calcite and magnesite.
If the end result is rock solid, the theory goes, it’s also going to be stable, and
won’t trouble the atmosphere and by extension society any time soon.
Oil and gas reservoirs, of the type Northern lights wants to use to stash
CO2 under the North Sea, are similarly helpful. They’re obviously porous and
can store a lot. We know this, because that’s where much of the oil and gas
we’ve been merrily torching for over a century first sprang from.
There’s no shortage of underground space. In fact, research suggests the United States alone
has enough subsurface capacity to store some 10.8 trillion tons of the stuff. Anxieties naturally
crop up around contamination of subterranean water courses, but in most cases the deep
saline groundwater systems at threat aren’t part of the drinking water system anyway.
For a long time, incidentally, scientists contemplated dumping C02 into the deep ocean.
At sufficient depth, carbon dioxide is denser than water, so it should stay in
place indefinitely. However, there’s no telling what that might do to fragile marine ecosystems,
and the somewhat unpredictable nature of powerful ocean currents make it all just a bit sketchy.
Far more exciting, is the prospect of CCU – remember, that’s Carbon Capture and Utilisation.
Lots of very clever people and startups are figuring out ways
of using carbon destined to float around in the atmosphere as handy terrestrial products.
Take these snazzy H&M sunglasses, crafted from CCU-based carbon-negative thermoplastics. Or
these carpet tiles by American firm Interface. Climeworks – them again – have figured out a
way of repurposing captured atmospheric carbon as the gas that makes your drinks
fizzy. Australian company Mineral Carbonation International wants to utilise carbon in bricks,
which would handily store a whole bunch of carbon securely for at least a century, part of the
firm's ambitious initiative to lock one billion tonnes of C02 into its products by the year 2040.
The great, sad irony of Carbon Capture and Utilisation is that,
for now at least, its main commercial use is the mucky business of EOR,
or Enhanced Oil Recovery. Under EOR, CO2 is pumped underground at drilling sites in order
to help drive precious crude oil reserves to the surface where they can be more easily extracted.
If you’re feeling squeamish about the sound of that, fair enough.
Somewhere around three quarters of all subterranean carbon sequestration
happens in the name of EOR. It’s good, in that carbon that would otherwise wind up in
the atmosphere is stashed out of harm’s way, but obviously bad in that it ultimately leads
to the burning of still more fossil fuels. And we really do need to start moving past that.
Still, encouragingly perhaps, a prominent EOR facility in Petra Nova, Texas recently closed,
after the pandemic-related oil price crash made EOR no longer financially viable.
In either case, it actually doesn’t actually matter from an Enhanced oil Recovery standpoint
whether the carbon used for pumping out oil comes from recovered emissions,
or virgin mined carbon. Which is of course cheaper, and sneakily preferred by the oil giants.
This brings us to the fundamental problem scaling up Carbon Capture schemes.
For now, there’s no great financial incentive
for any bright young startups to develop and scale their technology.
Electric cars, and to a lesser extent solar panels, are a shiny futuristic technology
that people are happy to splash out on. Elon Musk can grow as rich as he likes selling fast cars.
But carbon capture is a lot more humdrum, with the benefits only likely to be felt
many years or decades from now. It’s hard to market, and hard to get excited about.
It needn’t be this way though.
Carbon obviously has value. It’s useful. Policymakers just need
to find a way of making captured carbon more cost effective than virgin carbon.
In order to meet the International Panel on Climate Change’s target, removing 10 gigatonnes
of C02 net from the atmosphere by the middle of this century, a vast industry needs to be built,
and it needs to be built now. The Northern Lights project off the coast of Norway is
a promising start. Climeworks reckon about 80 million of its extraction units – which can be
placed more or less anywhere on earth, ideally near renewable sources of power – could make
a significant dent in atmospheric carbon. That sounds like a lot, but it’s roughly the number
of cars that are already manufactured every year. Where there’s a will, there’s a way.
In truth, Carbon Capture and Utilisation will only ever be a sideshow – much of the recycled carbon,
used for instance in food or alternative fuels,
will just end up back in the atmosphere at some point anyway.
Current technologies on the drawing board to, for instance, apply molten electrolysis
to alchemise recovered carbon into nanotubes that replace construction steel would be great,
but are too speculative to rely on at this early stage.
So for now smart subterranean sequestration is the path forward.
And with dizzying incentives on offer to whichever genius figures how to do that
at a useful scale – not least our mate Elon’s generous $100m Carbon-X prize
fund – hopefully the grubby profit motive will save our collective bacon after all.
Because as a civilisation, we really can’t afford
for carbon capture to remain an underground technology.
What do you think? Is there a better way of reducing atmospheric
carbon and averting runaway climate change? Let us know in the comments,
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