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, and don’t forget to subscribe for more
thoroughly captivating tech content.
