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 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.
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| Carbon dioxide emission by plants. |
This specific process, which employs sophisticated ammonia-based chemistry, successfully captures around a million metric tons of carbon dioxide every year, or 90% of the Saskatchewan plant’s emissions. The downside is the equipment to make that happen costs $1.3 bn. 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 carbon dioxide is stashed out of harm’s way, typically underground in secure rock formations. CCU, on the other hand, stands for Carbon Capture and Utilization. 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 Oygarden on the North Sea coast. From there, specially designed ships will ferry the noxious carbon dioxide waste out to sea, where it will be injected into storage reservoirs 2,600 meters 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 tons of carbon dioxide a year, which should increase to five million tons a year as the model – CCS as a service, in effect – proves its efficacy.
Orca
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 in Iceland. Conceived by Swiss startup Clime works, Orca catches its carbon via futuristic Direct Air Capture, essentially running gigantic banks of fans which suck carbon dioxide 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 carbon dioxide is of course central to the problem of carbon capture. Basalt rocks are ideal, not only because they’re very common, but because carbon dioxide reacts with basalts’ naturally abundant magnesium and calcium, transforming the unhelpful element into solid minerals likes dolomite, calcite and magnetite.
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 carbon dioxide 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.
In order to meet the International Panel on Climate Change’s target, removing 10 Giga Tones of carbon dioxide 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. Clime works 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.
In truth, Carbon Capture and Utilization 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 alchemies recovered carbon into nanotubes that replace construction steel would be great, but are too speculative to rely on at this early stage.
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