Direct Air Capture: A Lifejacket for Humanity?
I’m sure you’ve had the same thought that I had as a child when thinking about climate change; “Why not just suck out the carbon and call it a day?” And I’m sure that your 3rd-grade science teacher said the same thing, “That just isn’t possible.” Turns out, our 3rd-grade science teachers were wrong, we can literally suck the carbon out of the air.
How can we achieve this?
The technology is called Direct Air Capture (DAC) and has been around since 2017. Direct Air Capture technologies take in ambient air from the atmosphere and purify it by extracting the CO2 (read more on DAC here). To achieve negative emissions, the CO2 can be permanently stored underground in the earth which would essentially eliminate the CO2. The first company (that I’ve found) to take this approach was a Swiss startup called Climeworks which has a plant in Iceland. Their approach is to:
- Filter out CO2 from the atmosphere
- Mix it with water
- Inject it into the ground
- Use some fancy geology from their partners to turn that CO2 into stone.
You can read more about this technology from Climeworks here.
That’s it? We just inject carbon in the ground and call it a day?
Thankfully, that isn’t the limit of this technology’s potential. Here in Canada, a startup called Carbon Engineering is re-using CO2 and converting it to carbon-neutral synthetic fuel which can be implemented in our existing infrastructure. This Harvard affiliated startup has been backed by Bill Gates and has the potential to completely disrupt the oil industry. Here’s how it works.
Essentially, a massive fan sucks in atmospheric air and passes the air over thin plastic sheets coated with a chemical solution. The chemical solution reacts with the air to trap the carbon and create a liquid solution. It’s then purified and compressed into tiny pellets so it can be prepped for storage. The pellets are then heated up so that the pure CO2 can be:
- Injected into the ground (for net-negative emissions)
- Recycled to be used in the chemical solution which traps the carbon
- Recycled into synthetic fuel
A more in-depth explanation of Carbon Engineering’s DAC process can be found here.
So… why aren’t we doing this?
Sadly, there’s a bunch of reasons, and it gets worse the further we go down the list.
- It’s energy-intensive. The concentration of CO2 in ambient air is relatively low (approximately 1 carbon molecule out of every 2,500) compared to pulling CO2 out of an exhaust stream, where it is concentrated (approximately 1 carbon molecule out of every 10).
- It’s expensive. Currently, with Carbon Engineering’s estimate of capturing a ton of carbon being somewhere between $94 and $232, it’s cheaper to use renewable energy to prevent a ton of carbon from being emitted. However, at $94 it’s a viable option when compared to other CO2 solutions.
Those flaws listed above are some of the smaller problems with DAC (although they’re still big). One of the biggest problems with DAC is that to actually produce negative emissions, you have to burn your money.
Let me explain, the issue of climate change is that we are taking too much carbon from the geosphere (underground) and putting it into the biosphere (above ground). The image above outlines how much carbon we need to take out of the biosphere by mid to late 21st century. To reach the 2°C goal, we have to go carbon-negative. The way to DAC companies attempt to solve this problem is by taking carbon from atmospheric air from the biosphere and putting it back into the geosphere.
Here’s where your money is being burnt: If you put so much time, energy, and money to get this pure CO2. Why the hell would you bury it? There’s no incentive to bury the carbon other than trying to save humanity. Funny enough, nobody cares about that if it doesn’t make money (sarcasm). This is why Climeworks is selling its CO2 to greenhouses and why Carbon Engineering is making synthetic fuels.
In short, it’s just not realistic to go for negative emissions in the short-term. These companies are businesses, which means that they need to stay profitable in the near future so that they can scale their technologies. Thankfully, Carbon Engineering is doing this well with its synthetic fuels.
Carbon Engineering swoops in and saves the day?
Kind of? It’s hard to say right now, but there is a market for synthetic fuels. According to Carbon Engineering, it can be implemented in today’s infrastructure and could make carbon-neutral gasoline, diesel, and jet fuel.
This would drastically reduce emissions worldwide since transportation wouldn’t be adding new emissions taken from the geosphere. People would essentially be recycling carbon already in the biosphere. If that isn’t game-changing, I don’t know what is.
Here’s the TL;DR:
- Direct Air Capture (DAC) is a technology which aims to combat climate change by sucking in the excess CO2 from the biosphere and putting it back into the geosphere
- To achieve negative emissions we need to bury the pure CO2 that is harnessed through DAC
- Climeworks and Carbon Engineering (the two main DAC companies) aren’t doing this since there isn’t a monetary incentive. Instead, they sell their CO2 or turn it into something useful
- DAC has some problems right now and shouldn’t be treated as something that will save humanity in an instant
- Carbon Engineering is using their CO2 to create synthetic fuels that can be implemented in today’s infrastructure
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