Why do we need direct air capture?

Dear Friends,

For the past few months, my colleagues and I worked on the major review of direct air capture. I am happy to announce that this review has been just approved for publication in Enegy and Environmental Science, one of the major journals in our field. It may take some time before this paper is available on the journal website and it will be an open-access one.

But because you support my work, I wanted to share a few thoughts that I've learned during this journey before it is published.

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Why do we need a direct air capture?

If you follow me on LinkedIn, you probably already noted that I find the idea of removing CO2 directly from the air exciting. Both from the climate and chemical engineering point of view! At the end of the day, it is a really difficult chemical separation - a challenge that we need to crack in order for DAC to become viable. But I'm getting ahead of myself...

Why do we need direct air capture in the first place? Well, if we’re late in pursuing industrial decarbonization, for example, by delaying the deployment of carbon capture, hydrogen, renewables and nuclear, then by 2050 or 2060 we wouldn’t become the net-zero society.

The recent IPCC report showed us that "observed global temperature is increasingly higher than that simulated accounting for natural factors alone, with human activity explaining all the deviation".

The result? Increased global surface temperature, increased sea levels, more frequent and intense heavy precipitation events and heat waves, just to name a few.

Image source: IPCC

If we don’t transition our economy fast enough to achieve the necessary emission reductions, we will need technologies that will help us mitigate drastic climate change. That’s where greenhouse gas removal technologies, such as direct air capture, can play a significant role.

Note that GGRs are NOT MEANT TO BE A GOLDEN TICKET for organisations to keep using fossil fuels. Although GGR can remove CO2 directly from the air, we first have to decarbonize our economy as much as possible before relying on them.

But even if we do our best in terms of deploying low-carbon technologies, we might still have some small areas of our economy that cannot be decarbonised. This is mostly because some of the industries are distributed, such as transportation. As a result, it might be difficult to electrify everything or switch to synthetic fuels. That’s where potentially we might have the requirement for direct air capture.

If you look at the report from the Royal Society, they estimated that we would need about 810 Gigatonnes of CO2 removals by 2100. That’s quite a significant amount of GGRs, and that’s why my work actually focuses on this issue.

Why do we need to develop direct air capture now?

This is a valid question. If we don't need this technology now, in principle, why do we need to focus our efforts on developing it right now? Well, here is the thing. If we need to start deploying DAC at scale in about 15-30 years, we cannot wait and do nothing until that technology will become necessary. It will simply be too late.

The same thing happens to CCS that have been now in development for more than two decades and we only see large demonstration projects being deployed now.

That is why we cannot wait, we need to act now.

The recent state of DAC

A lot of development has happened over the past year or two in the area of DAC, but this was mostly driven by a small number of start-ups. This is because DAC offers unique advantages over other GGRs, such as reduced water requirements and land requirements.

But due to limited development efforts, the current designs and configurations will result in the cost of CO2 removal of about 400-800 €/tCO2. Expensive? Check how much you paid for CO2 if you needed it for your business.

Also, I have seen some DAC configurations that were driven by... fossil fuels! What a waste of resources and potential. Such technologies achieve carbon efficiency of about 9-17%, meaning that these are only slightly carbon negative. On the contrary, when DAC is driven by nuclear or renewables, their carbon efficiency is 85-95%. This means that for each 1 kg of CO2 removed from the air, only 0.05-0.15 kg is released back to the environment over the life-cycle of DAC operation.

Now the economic figures don't look encouraging - but hear me out. DAC is only in its infancy. I strongly believe that by achieving breakthroughs in process design, we can get the cost of CO2 removed down to below 100 €/tCO2, a figure comparable to CCS from concentrated CO2 sources.

Want to support such breakthrough research? Get in touch!

Final remarks

Thank you for reading this episode of Net-Zero Academic. I trust you now understand the role DAC has to play in getting us to net-zero.

I'll host a Next-Zero Academic Live session next Wednesday and I will share details on my LinkedIn profile shortly. Make sure you sign up for the event!

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If you did not like something, please do let me know too! Also, if there is anything specific that you would like to learn about, please do let me know!

Thank you,

Dr Hanak

PS: If you enjoyed this newsletter and learned something new, share it with a friend!

PPS: If you need consultancy or training in process design and process economics, green energy transition, industrial decarbonisation, carbon removal technologies, I am open to discussing how we can collaborate together! Schedule a meeting here.