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🌳 "Using Naturally Occurring Minerals for Direct Air Capture & Climate Justice"


Photo by Calvin Chai / Unsplash

Host: Guillaume De Dorlodot
Guest: Noah McQueen | Co-Founder | Heirloom
Category: 🌳 Carbon Capture | Carbon Mineralization

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Podcast’s Essential Bites:

[5:30] “Heirloom is a direct air capture company that uses Earth abundant naturally occurring minerals to remove CO2 from the atmosphere and store it in a permanent manner.”

[9:27] “Throughout my time in research, there was really this emphasis on policy levers needed to enable scaling carbon capture and carbon removal to meet the needs of the climate crisis. So we started to talk about this huge gap between the science and understanding at an academic level and the need to scale and commercialize these systems for massive gigaton scale carbon removal by mid century.”

[13:55] “While we work to decarbonize as much of the global economy as we can, we also have to offset the continuing emissions from […] hard to abate sectors. And I think this is where direct air capture really comes in. You can offset those emissions, essentially, by removing CO2 from the atmosphere directly to reach net zero. There's another need for direct air capture, though, and this comes from some countries have emitted more CO2 historically than other countries. So direct air capture really comes in and allows those countries to take responsibility for some of their historic CO2 emissions by pulling it back out of the atmosphere.”

[14:47] “When we look at the current landscape of direct air capture, there are really three or four processes: we've got liquid solvent, solid sorbent, mineralization based, and electrochemical approaches. And each of these systems is fundamentally similar. They capture CO2 from the atmosphere at roughly ambient conditions and they use some kind of capture agent. And then they release the CO2 at some elevated condition, which is typically a higher temperature, a lower pressure, or some kind of a change in electrochemical potential. And that allows the process to capture a pure stream of CO2 that can be stored or utilized.”

[15:44] “The largest direct air capture plant [by Climeworks] currently removes about 4,000 tons of CO2 per year. […] But we emit roughly 35 gigatons of CO2 a year. So this means it takes roughly 4 seconds for us to emit the amount of carbon that we currently remove per year using direct air capture. So I think this really emphasizes the need for rapid scaling of these systems coupled to continued innovation.”

[29:32] “Our process […] uses naturally occurring Earth abundant minerals, which is calcium carbonate or limestone. […] We send it into an electric high temperature reactor. So inside this reactor, calcium carbonate releases a CO2 that's kind of caught up in its structure, and that produces a pure stream of cO2. We can capture that and sequester it underground. And then we result in calcium oxide […] and oxide is super thirsty for CO2 and atmospheric conditions. […] This calcium oxide can be laid out on trays and those trays put into racks […], [where] it naturally uptakes CO2 from the atmosphere and forms calcium carbonate. […] And while this process typically takes months to years, to complete at ambient conditions, we've actually accelerated this to less than a week. So calcium oxide to calcium carbonate in less than a week. And after that carbonate is reformed, it can be fed back into that high temperature reactor, where once again, releases its CO2 and forms calcium oxide, capturing that CO2 this time from the atmosphere and using that calcium oxide to capture more CO2 from the air. So it's a cyclic process going between calcium carbonate and calcium oxide.

[32:46] “Per cycle, it takes about 1.4 tons of minerals to capture a ton of CO2. But if that material is used for hundreds of cycles, then you're capturing hundreds of tons of CO2 per ton of mineral over its lifetime. […] With respect to scaling to a billion tonnes, […] our next step is derisking the integrated system. […] We think if we can keep this pathway of scaling quickly and doubling 10X in capacity, we can reach the billion tonne target by 2035.”

[42:56] “Heirloom does three important things that sets our technology apart from other director capture approaches, and gives us that potential to achieve costs less than $100 per ton in a really scalable way. So the first one is, […] we use these low cost Earth abundant minerals to capture CO2, which is very different from approaches that use highly engineered specialty materials. […] The second aspect [that] is novel to Heirloom’s process is that we perform the capture process allowing the mineral to naturally take up CO2. So this doesn't require any kind of forced airflow and minimizes the energy requirements associated with actually capturing the CO2. […] And then finally, […] we're designing a modular approach that allows us to quickly iterate and repeatedly manufacture the same infrastructure. So this means we can really leverage mass manufacturing and the technology learning that comes along with repeated manufacturing and iteration to achieve that below $100 closer to $50 per ton cost.”

Rating: 🌳🌳🌳🌳

🎙️ Full Episode: Apple | Spotify | Google
🕰️ 51 min | 🗓️ 06/25/2022
✅ Time saved: 48 min

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